Archive through March 15, 2008

 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 30
Registered: May-07
Stephen,
Yay! You are the first person I've heard from who actually has this problem. It is a known problem for the European version of the AM15. What is happening is the fuse is opening because of the onrush current when it's powered up. The fix for it is simply changing fuse types. The new fuse type has 3 times the onrush current handling capability than what you are probably currently using. Getting these particular fuses may be a problem but presumably you can get them from Bose. Here is the bulletin in a nutshell in quotes:

"Bulletin Part Number: 267216-B5
Product: Acoustimass 15 Series II
Subject: Fuses blowing in 230V units.
Disposition: All
Symptom: Acoustimass 15 Series II is dead.
Reason: A large AC-inrush current upon turn on is blowing the fuse.
Solution: Replace existing fuse 177311-01250 (Littelfuse 218 series 1.25A) with 282594-1250 (Bel 5VT series
1.25A). Note: new fuse has 3 times higher I-squared-T rating."

The long numbers with the dash are the Bose part numbers. Good luck}
 

New member
Username: Vespoli

Post Number: 1
Registered: Jan-08
Hey, I have a control pod for a Bose Companion 3 series 1 system that needs a new cable. I've taken the pod apart and it would be a simple swap out. Does anyone know if it's possible to get Bose to send repair parts and if so how to go about getting a part? I know Bose is very particular about getting you to send back in for repair but this fix could be really easy for me. thanks

Chris
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 31
Registered: May-07
Chris,
I know this isn't what you want to hear but there are no "repair parts" per se for the control pod. The control pod IS a part unto itself and is listed in the maunal as "non-repairable". You can order a new one from Bose and that part number is 307874-001 for the series one Companion 3 and 307874-002 for the series II. I'd be willing to bet if you could get a cable it would cost as much as the whole pod. If I remember correctly that cable has about 9 pins in it.
 

New member
Username: Olof

Post Number: 3
Registered: Jan-08
Hey everybody!
I'm tangeling with getting my system to work correctly...

Ok, I was stupid enough to buy a separate set of 5.1 jewels (for the Lifestyle 48) and now I can't get the sound that I want. I even bought a separate Acoustimass subwoofer but it sounds that the jewels is to high in treble, if I test the system only a bit over normal talking-volume it feels that my ears are going to fall off because of the high treble...

..what to do??? I'm getting so frustrated that I feel like using my 5 jewels as paperweights in my future...

I also tested them with another subwoofer, but there was the same problem...

Is the jewelspeakers "higher" in treble than the other bose-satellites? I have listen to many demos of the bose-systems and they all sound so great, why can't mine also do that??
My small satellites in my 2.1 creative-system (for 120$) connected to my computer sounds 100times better than the jewels...

Anyone? Any tip/info is good for me in this situation!
 

New member
Username: Pretenda

Post Number: 1
Registered: Jan-08
Hi Mark / Everyone,

I have recently acquired an Acoustimass Powered Speaker System, and i am missing the 5 pin DIN to two RCA's and 3.5MM jack cable. I have all the connectors to wire this up, but I do not know what pin goes to where. I would much rather not have to buy the cable, I already have everything I need :-) Can anyone help me out here?

This is the unit I have:
http://products.bose.com/pdf/customer_service/owners/og_am5p.pdf


Cheers,
Matt
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 32
Registered: May-07
OK Matt, here's the scoop. On the sub side the pinout of the 5 pin din connector is as follows.
Pin 1: 12V to power sub. Connect to the tip of the 3.5mm plug.
Pin 2: Common for both right and left channel (-)
pin 3: Left signal (+) to tip of left RCA plug.
Pin 4: Chassis ground. Connect to shaft of 3.5mm plug.
Pin 5: Right signal (+) to tip of right RCA plug.
Do not connect the common for the two signals to ground in the cable. Use shielded wire for the signal connections and the 12V line. Good luck!
 

New member
Username: Pretenda

Sydney, NSW Australia

Post Number: 3
Registered: Jan-08
Mark you are an absolute legend! Thank you for this, I could not find it anywhere else on the net. Works like a charm! You saved me about $50 for this lead (ridiculous I know) Thanks again!
 

New member
Username: Mikkap

Post Number: 1
Registered: Jan-08
Hi there....I know other people are experiencing the display problem with lifestyle 12 and the answer is change a capacitor. Please identify the exact location of this capacitor (33ufd @ 63vdc). The comment was on the left side of the top pc board. All that is on the left hand side is the actual display and further left the earphone board. Where should I be looking and is it possible to show a photo or diagram? Any help would be most appreciated. Regards Mike
 

New member
Username: Brownc

Post Number: 3
Registered: Jan-08
Mike,

If you read Mark's post above https://www.ecoustics.com/cgi-bin/bbs/show.pl?tpc=1&post=1390678#POST1390678, you'll read that it's capacitor C19 (just below and left of the display). He suggested a 33ufd@25VDC, 33ufd@50VDC, or 47ufd@50VDC. My local Radio Shack didn't have those, so I tried a 47ufd@35VDC and it seems to be working fine.
 

New member
Username: Mikkap

Post Number: 2
Registered: Jan-08
Thanks Charlie.....don't know if my unit marketed in Australia is the same. There just isn't any capacitor in that location on that board....this is a series 2 lifestyle 12 and maybe that also is the reason for any changes. Regards Mike
 

New member
Username: Brownc

Post Number: 4
Registered: Jan-08
Bummer...maybe you could post a picture?
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 33
Registered: May-07
Mike,

You are correct in your assumtion that the part is in fact in a different location on the CD5VII consoles. In this version the cap in question is C17 and is located on the bottom board, front left hand side BUT... this will not solve your problem. A dim display is NOT the same as one that will not come on at all. That cap couples the AC voltage coming into your console to the filiment of the fluorescent display. There is also a -15 volts superimposed on this "filiment" supply that is used to develop the potential between the anodes and cathodes of the display elements. I suspect that -15V is not correct and has ripple in it and (this you're not going to like) the individual elements in the display "burn" if you will, and get very dim. Changing the filter caps on the -15V line might help some but at this point your display is for all intent and purposes "worn out". It will never be as bright as it once was and will appear "splotchy", meaning there will be bright spots and lots of dim ones. This is one that needs to be serviced and the display will have to be replaced and the power supplies refurbed. Sorry for the "bad news" Mike.

Please note; "Lifestyle" systems are just that... systems and they consist of individual components. When refering to any particular problem try to reference the components in question. For example in this case Mike has a Lifestyle 12 series two. It consists of the Acoustimass AM25II sub and the CD5V2 console (and all the little cubes, cables and such). The model numbers for consoles are on the bottom or back of most units and for the subs it is usually a foil sticker about 4" x 5" mounted on the bottom of the sub. I am going to try and attach a Word.rtf file to this which is a list of all the Bose system names, the media center type and the corresponding powered speaker.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 34
Registered: May-07
OK, let me try that again.
application/mswordUpload
SystemList.rtf (2.7 k)
 

New member
Username: Luis_xc4

Post Number: 1
Registered: Jan-08
Mark, Great stuff posted in the board, thanks.
I have a lifestyle 5 with the display inop problem, I thought it could be the same fix as the ls 12, but doesn't look like. The lifestyle 5 has nothing on the lower left side of the display. Do you know which cap # (cxxx) is the one I should change to fix the problem on this LS5?

I didn't find the exact console number, nothing in the back, and on the bottom just says "lifestyle model 5 music center" and a little sticker with 2V and 193573 rev 06

thanks very much.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 35
Registered: May-07
Luis,
If you have a Lifestyle 5II or 5III then indeed you have the CD5V2 media center as the console portion of the package. The 2V on the bottom of the console indicates it is this version. See my post above as it references that exact unit. Your display problem very well mat not be replacing C17 on the lower board.
 

New member
Username: Guiambros

Post Number: 1
Registered: Jan-08
hey mark and all,

do you have any idea how to open the subwoofer on the bose companion 3 series I (P/N 272079-001)?

I removed the 5 screws from the back, but now I'm stuck. Tried to remove the sticker, but there's just a metal round circle with two small holes and it don't move. Do I need to use any special tool to open it?

any help would be greatly appreciated. thanks in advance!!
 

New member
Username: Luis_xc4

Post Number: 2
Registered: Jan-08
Ups, actually the display began fading out a couple of months ago until it became totally dark. However all of the display elements are not working, if some are worn out shouldn't some (and mostly the ones I never use like the AM/FM) still work? Also if indeed I change C17, then anyhow you are saying that it will damage the display sooner or later because of the fault in the -15 voltage being sent to it?

thanks again.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 36
Registered: May-07
Luis and Mike,
Both of you try this and it should help you both get the best from what your display can deliver. Replace C17 (33ufd @ 63V),C12 (100ufd @ 25V), C15, (100ufd @ 25V) and C16 (either 220ufd or 100ufd @ 25V.) For C16 use the 220ufd if you have the European version of the CD5V2. All these caps are huddled near each other on the bottom board, left front quadrant. Once this is done all the supplies for the display portion of the system will be correct. Cross your fingers and best of luck.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 37
Registered: May-07
Guilherme,
The dead giveaway here is that you removed 5 screws... there are 8. You need to remove the volume knob and VERY CAREFULLY remove the label that runs vertically (yes the entire label). Behind the label you will find three more screws that need to be removed before you can open it up. Use double sticky tape to remount the label when you're finished mucking about inside and have reassembled the cabinet.
 

New member
Username: Guiambros

Post Number: 2
Registered: Jan-08
bingo! thanks a lot, mark. Yes, there was other 5 screws behind the label, besides the other 5 outside. Total 10 screws on Companion 3 Series I, plus the knob.

any idea how much would cost the PN 280066-001 (or with the full internal circuitry of the subwoofer) and how can I order it from bose? my left channel is not working, even though the soundcard/cable/speakers are all fine.

any ideas to troubleshoot the card without the schematics?

thanks a lot, and you rock man!

best,

gui
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 38
Registered: May-07
Gui,
No, no ideas on how to do that without prints. So why try to troubleshoot without them? If you will email me I will send you the ske's and the board layouts in .pdf format.
 

New member
Username: Luis_xc4

Post Number: 3
Registered: Jan-08
Mark,

THANK YOU!
I changed the 4 caps, and the display is alive again.

best regards.
 

New member
Username: Pretenda

Sydney, NSW Australia

Post Number: 4
Registered: Jan-08
Mark,

Thanks for your help before. I have another question for the master! I have a Bose Freespace Business Music System (stereo), which comes with 4 cubes - each has its own input in the unit. When I attempt to remove two from the system, I no longer get any sound. (I don't want them on this system anymore) Is it OK to bridge these terminals to have sound only come out of two of the speakers or will I run into problems?

Cheers,
Matt
 

New member
Username: Unclewayne

Post Number: 1
Registered: Jan-08
does anyone know how to take apart the 321 speaker? please help!
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 39
Registered: May-07
Wayne,
If you're trying to get at the actual speaker then forget it. It's a sealed cabinet and must be dismantled and then all glued back together again after speaker is replaced or baffle reglued etc. Getting at the amp portion is easy enough by removing the appropriate screws from the back. Hope this answers your question.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 40
Registered: May-07
Matt,
Your system has two seperate amplifiers in it for right and left output but two speakers per channel and they are internally wired in series. This is why you get no sound at all by removing one from each channel. The amps are rated at 50 watts for the satellites and the impedance of the sat's is 4 ohms. You may install a 4 ohm resistor (rated for at least 30 watts depending on how loud you listen to it) in place of the removed speaker but don't just jump the two vacated pins as this could be potentially harmful to the amplifiers.
 

New member
Username: Jksmeko

Russell, KY USA

Post Number: 1
Registered: Jan-08
Mark
Acoustimass 7 sats work fine bass very weak to no power any thoughts on repair? fuse looks ok do you think it could me the 100 resistor?
 

New member
Username: Mattp35

Post Number: 1
Registered: Jan-08
I have a bose acoustimass Multimedia speaker system. While the music is playing, all of a sudden the powered base module will shut off. To turn it back on, I have to turn the power off and turn it back on. Does anyone know what the problem is and how to fix it
 

New member
Username: Hdh

Post Number: 1
Registered: Jan-08
Mark,

I have an Acoustimass 25 with the symptoms that point toward replacing CR400. Can you give me the Bose part number for this 400MHz crystal or where else I can buy one? Thanks for your help and I'm still amazed at your knowledge of all these Bose systems.
 

New member
Username: Nrsesh

Post Number: 1
Registered: Jan-08
Mark,

I have Acoustimass 15. Worked fine for last 6 years. Sub woofer seems to be not working as there is no Bass or the real effect of the home theater system.

I have no idea why it is not working. Appreciate your help in fixing this please.

Thanks for your help.
Ram
 

New member
Username: Dfranco

Post Number: 1
Registered: Jan-08
Hi Mark
Someone gave me a Bose Subwoofer and I had access to the Box as explained on this thread on May 15 2007. I just only want to use the amplifying board and I will need some help with the electronics.
The Board has 5 TDA7294 IC's and some TIP142 and TIP147 Transistors. It seems to be that the Subwoofer speaker is driven by 4 transistors (2xTip142 and 2xTIP147) and the others speakers by the TDA's. The PCB has a flat 18 pin connector used for control and input signals, but unfortunately I don't have the pinout and haven't been able to power up the amplifiers. I have the TDA's datasheet and could find that they have Standby and mute control pins. Fortunatelly I followed the pcb's tracks and could identify the control pins on the 18 pin connector for the TDA's. At this stage I have some pins identified, but I will need help to identify the rest of the pins, they are as follow:
18 pin connector:

PCB Ground (-): Pin1,Pin11, Pin15, Pin17
Mute/Standby control for TDA's : Pin2, Pin3, Pin4
(Voltaje level???)
Pin 2 controls 2 TDA's
Pin 3 controls 1 TDA
Pin 4 controls 2 TDA's

Unfortunately I haven't identify the rest of the pins, there are too many additional transistors and SMD components, which makes it very difficult to follow. I suppose the Subwoofer speaker amplifier (driven by 4 TIP Transistors) must have a standbay and mute control as the TDA's. I will need to identify the signal inputs for the amplifiers as well. I would appreciate if someone can help me identifying the rest of the pins for the 18 pin connector or if anyone has the pin out for this board.

Thank you very much for your help
Dorian F
 

New member
Username: Pete4kof

Post Number: 1
Registered: Jan-08
could any one give me some information on where i can purchase a glass fuse for acoustimass 3 series 1v speaker system or give me a idea of a replacement available..these speakers are a few years old and always been loyal until a positive was put to the negative by wife lol..there is no marking on the fuse and no one have been able to help other than bose who want £130 just to look before repair....i am based in england any information would be grateful
 

New member
Username: Showpiecerodent

Sutton Coldfield, West Midlands UK

Post Number: 3
Registered: Dec-07
Peter. See my last entry above and Mark's reply, 2 below it. (Thanks again Mark) My unit is a series 3 AM15 and I have replaced the fuse at least 10 times. Make sure you rplace it with an identically rated fuse and make sure if it is a time lag fuse (shown by a T), that you replace it with the same. Good luck.
 

New member
Username: Kimba07

Post Number: 2
Registered: Dec-07
Damn,

Took my non-functioning Acoustimass from Bose service centre just the other day re: after 1 month sitting at the service centre due to holiday seasons!!!! Technician said "You better off getting a new Acoustimass and it costs over AUD1k." I said "Forget it mate!". He still charged me AUD44.00 for dismantling and assembled it back to its non-fucntioning condition. No brownie points earned there for sure. 5 freaking weeks later, left with the same problem.
 

New member
Username: Pete4kof

Post Number: 2
Registered: Jan-08
stephen thanks for advice i only live up road from you. can you tell me where to pick these fuses up from tried loads of places and struggling to find them..
kim foo sorry to hear your having problems to .thanks for your reply mate
 

New member
Username: Showpiecerodent

Sutton Coldfield, West Midlands UK

Post Number: 4
Registered: Dec-07
Peter. I am awaiting a reply from my Bose dealer. As soon as I am able to get the ones Mark recommended then I will let you know. ...or you can contact then yourself on 0121 3213000 but you may be back into the realm of £130 fee. The fuses I have been using so far are 1.25 Amp Time Lag - the same that was in the unit when I got it - but beware - my system is series 3, yours is 4? and they may be different fuses. Are you sure it is unmarked? It may look unmarked but if you look close enough, you should see markings around the end caps. I can't imagine anyone making a fuse without a rating on it. Anyway, I got my fuses from Maplins in Erdington. Regards, Steve.
 

New member
Username: Olof

Post Number: 4
Registered: Jan-08
Hi again!

Doesn't anyone have the jewelcubes? Do they play "sharper" than other bose-cubes? I can't get mine to play with good sound even if I have a acoustimass 5 subwoofer. It feels like my jewels only delivers treble??

Please dudes, help me out here!!

regards
olof
 

New member
Username: Mmacmobile

Mobile, Alabama Mobile

Post Number: 1
Registered: Jan-08
Mark: Thanks for the past postings on the display fix for the LS 12 system. I have been using my system without the benefit of that display for a few years after an Atlanta authorized repair center told me it would be $100 to replace a faulty component. I bought the schematics but never got around to troubleshooting it. Is there any trick to opening the case to get to the CCB with the open C19?
 

New member
Username: Mmacmobile

Mobile, Alabama Mobile

Post Number: 2
Registered: Jan-08
Again, thanks to Mark and those who asked the question about the same problem I had with an inop display. Popped the lid, replaced the cap and voila', I have lighted segments! I can now see what I am doing and it is like having a new system to play with. All for about 10 minutes on this forum, 15 minutes of repair work, and 25 cents for the component...instead of $100 and shipping costs for the authorized repair station(not to mention the delay in getting it back); now was that a good deal or what? Roll Tide!
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 41
Registered: May-07
Mathew Pant,
I need to know the model number of your Acoustimass speaker in order to help you. Sounds like an AM25II or AM30II but....?

Ram Prasad,
Your problem is probably one or two open chip resistors on the top board inside the subwoofer.
If the fuse is not blown and it still won't power up then this is most likely the problem. The two resistors in question are visible on the PC board. They are chip resistors, mounted side by side and will be marked "200" in small white letters. The "200" means "20" with "0" order of magnitude or 20 ohms each. They are paralleled which makes the resistance = 10 ohms. Replace them with a single 10 ohm 1/4 watt resistor available from Radio Shack.

Dorian,
I responded to you in an email but haven't heard back from you. ???

Peter Prime,
The fuses YOU are looking for are 1.5 amp slo-blo, (5x20mm). The fuses Stephen is waiting on are only 1.25 amp so you might rethink your approach.

Michael MacIver,
There are 5 screws in the back of the CD5 unit. You will see also 5 slots in the back of the unit. while prying up slightly on the back left corner, insert a small flat head screwdriver in the leftmost slot. What you are doing is releasing a plastic catch holding the top in place. After releasing (or breaking) the first tab, move on to the next and so on. Please note: there are two halves to the top panel. Remove the left side first and then the cover over the CD player. Having never done this before you will no doubt break one or more of the little plastic tabs but don't panic, it won't hurt anything (except the defenseless plastic tabs) and the screws secure the top anyway. I've opened hundreds of these things and I still break a tab now and then.

Olof,
Last but not least... I really don't know what to tell you. I can fix the electronics but the subjective audio aspects of the speakers is out of my realm of expertise. Sorry I can't help here.
 

New member
Username: Dfranco

Post Number: 2
Registered: Jan-08
Hello Mark,

I just sent you an e- mail, thank you
 

New member
Username: Zqsus

Post Number: 2
Registered: Jan-08
Hi Dorian,

I wonder if you can share the information Mark sent to you. I have the same questions, and I have been waiting for the answers from Mark in the past week. But since he only responded to you privately, can I have the answers too? I appreciate it. The sub-woofer I have is an AM 25, it has the same 18 pin connector I believe.

zqsus@yahoo.com

Hi Mark,

Thank you very much for your great posts. I hope you don't mind I asked Dorian for the information. I know you have been helping lots of people and may get lots of emails. I just do not want you to repeat your work, so I am asking Dorian to pass it on.
 

New member
Username: Dfranco

Post Number: 3
Registered: Jan-08
Hi Pat,

Tomorrow morning I will post or send you an e-mail of what I found experimenting my self. Will be a pleasure.

Good night
 

New member
Username: Vanhootz

Post Number: 1
Registered: Jan-08
PLEASE HELP!

Surround mode not working on
Acoustimass 25 series ll lifestyle 5 amp :-(

I recently changed the fuse (3amp 250 volt slowblow fuse) in the sub as it was blown (i could easily see it)...
That enabled my system to work in stereo & stereo with
center mode...Hoorah!
I have tested the surround speakers in the regular left & right outputs & the speakers do work just not in the surround outputs

Is there another fuse i have to replace to enable surround mode?
Thank you so much for any input you can offer...
 

New member
Username: Zqsus

Post Number: 3
Registered: Jan-08
Bose AM25II possibly fixed!!

Dear Mark,

This is Pat. Thank you for your help!! Short story: I found the U200 is holding the reset signal (low) for U202, so there was something wrong. Then I noticed the 40Mhz crystal is burned. Then I remembered your first one or two posts........ I wish I had read your post more carefully.... I am going to get the crystal since I have the part number already. When it is fixed, I will post it and send you a bottle of wine :-)

Have a good day. Your help means a lot to me.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 42
Registered: May-07
Glen,
Your AM25II can operate in 3 modes. Stereo, 3-channel (Rt & Lft front + center) and surround. In surround mode there is a seperate volume control on your remote for the rear channels (surround) and I suspect that volume is turned all the way down. I can think of no senario where you can have 3 of 5 channels working on an AM25II and have it be an electronic "problem". Put the system into 5 speaker mode, set a reasonable listening level with the main volume control and then try turning up the surround volume.
 

New member
Username: Vanhootz

Post Number: 2
Registered: Jan-08
Hi Mark,
Thank you very much...it works
Initially i was turning the surround volume up on remote
& nothing, but now it just works!!
Now if there was only a way we could vote Mark Burgess
for President?......
Glen
 

New member
Username: H3grue

KobeJapan

Post Number: 1
Registered: Jan-08
First of all: Thanks so much for the valuable information in this board. I'm a newcomer here, and I have a problem with my bose, that I could not find a report on so far.

The details:
My Bose is Lifestype 20 Serial CDM20B115323
with Powered Speaker LSM20CU113188
Since a few weeks I observe clickings in the sound.
Before it started with a few impulses per second, but now it goes to medium speed like a "mashine gun".
I checked the powered speaker system, but there seems no place having a flash-over on a printed circuit board.
Instead, it seems to originate from the Radio/CD/Box.
On mute it does go nearly quite, on volume it does not react - unless volume goes to absolute minimum: Then its sound becomes more noisy!

I'm an old radio amateur, now employed in power electronics in Japan. Handling hardware thus should be not a big problem to me.
But there is no circuit diagram!

Did somebody already observe such noise impluses?
Is it a ceramic capacitor having a defect?
Can I get a circuit diagram to search more in depth?

Thanks again!
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 43
Registered: May-07
Horst,
What you're describing does not conjure up any "Oh yeah, I remember that problem" in my mind so you will be faced with troubleshooting on the CD20. Email me and I will supply you with the prints and layout for the CD20 media center. You may have power supply problems ie. leaky or dried up filter caps or any number of digital problems too numerous to note. Let's start with the print and go from there. I will also include instructions for opening the CD20 which is put together in a rather unconventional way.
 

New member
Username: Ricardolozano

Post Number: 1
Registered: Jan-08
Hi Mark. I have a BOSE PS28II SUBWOOFER problem:
I dont know if it's the AM15 part or not but inside the part number reads: 268573-001 on the pcb plate.
The main fuse looks ok, but besides that, I looked and replace the 100 (10 ohm)resistor, but before i connected it I looked the 2 triacs or mosfets with the following number both equal: P9NB50 (one of them broken) and a integrated circuit L6598D
with a little hole, I suspect its shorted too. I've measured the 2 triacs or mosfets and they reads 0 ohm in the first two pins on both transistors, Quetion; If i repalce the 10 ohm, the 2 triacs, and the IC do you think thats all i have to replace or which more parts u recommend me to change?
Thanks a lot
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 44
Registered: May-07
Ricardo,
Not to discourage you but what you are dealing with is a switchmode power supply and if you are not well versed the field of electronics and know what you're doing, you're getting in over your head. First of all the primary side of that supply is upwards of 320V DC and the circuitry is very involved. From what you've indicated you have had a major failure in the power supply. My suggestion is LEAVE IT ALONE and seek professional help repairing that sub. I can almost guarantee that what you've found wrong so far is only the tip of the iceberg. If you try and fail you run the risk of damaging more components in there that may be OK at this juncture. Not to mention that finding those parts will be a major pain in the... nether-regions.
 

New member
Username: Ricardolozano

Post Number: 2
Registered: Jan-08
Thanks for your reply Mark; I've been in electronics about all my life. I'm 37 y old.. I'm an Engineer and have an electronic appliances repair shop. But I've asked you about Bose because is my first time with these brands, Can you recommend me which parts to check besides that? I'd never scare about 300 volts nor 35,000 volts on a tv set, I just want to know If there's a way to fix this board,please help me. Thanks again.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 45
Registered: May-07
Ricardo,
If that's the case then email me and I will send you the prints and the manual for the LS28 sub. The parts list is in the service manual.
 

New member
Username: Zqsus

Post Number: 4
Registered: Jan-08
AM25II problem (no sound) fixed:
A 5.1 ohm fusing resistor replaced.

Initially, I thought it was the 40MHz crystal failed. Actually no.

The transfomer gives out DC +/-34 Volts supplies as well as DC +/-17 volts supplies. The +/-34 volts power is regulated to +/-12 volts then +/-5 volts. The +/- 17 volts is regulated to 3.3 volts. The 17 volts power supply is generated on the power amp board. It goes to the DSP board via the 18 pin connector. Right before it goes into the 18 pin connector, on the power amp board, there is a 5.1 ohms 2W fusing resistor. It is this resistor that was opened. After replacinig it, system works just fine (for two days now). As Mark mentioned, I did looked at the speaker driver amps, they look fine.

I don't know if this is a common problem, but hope this helps a little bit for some of you. Thanks Mark for all the help.
 

New member
Username: Kw1997

RiyadhSaudi arabia

Post Number: 1
Registered: Feb-08
Hi Mark
I have a lifestyle 28 (bought in US 120v/50-60 but use it in Middle east using a stepdown transformer 50/60 HZ). This system used to work fine until i moved to another city and had to re-wire the speakers again. and now there is no sound from either the headset or the speakers although the media center is playing the setup disk shwing picture but no sound. i suspect the sub. I have no knowledge of electronics.
I went into settings>sound status> says "speakers not connected".

Will appreciate if you can suggest something as there is no Bose support in Middle east. i will probably have to sen the unit to US. but i want to make sure which unit to send, the sub or the Media center.

Thanks

Joe
 

New member
Username: Wifehatesit

Post Number: 1
Registered: Feb-08
Hello,
I'm not sure if anyone else has(Had) this problem, but all of a sudden the Center Channel of my Bose Lifestyle 20 system has stopped working. The other 4 speakers + the Subwoofer are working fine. I have to now use the system in Stereo (2 speaker) mode only..
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 46
Registered: May-07
Nick,

Turn the remote control over and read what it says about setting the volume level of the center speaker. I'm betting that it has been inadvertantly turned down all the way and it that condition, the main volume control will have no affect on it.
 

New member
Username: Kieron_amos

Barnsley, Yorkshire England

Post Number: 1
Registered: Feb-08
hi there i have just bought Acoustimass 9 Powered Speaker System with lifestyle 5, and i am missing the 8 pin DIN to 2 RCA's and 3.5MM jack cable, could anyone help with what pin goes where, many thanks kieron also the dispay doesnt come on the lifestyle person i got it off said it needed re gasing, any ideas
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 47
Registered: May-07
Kieron,
For the answer to your display problem see my December 13th, 2006 posting above. You can use a 47ufd at 50VDC if you can't find a 33ufd.

As far as the cable goes Pin 1 (12v turn on signal) is connected to the middle ring on the 3.5mm plug. Pin 2 is left signal, pin 3 is left ground, pin 4 is right signal, pin 5 is right ground, pin 6 is serial data in and is connected to the tip of the 3.5mm plug and pin 7 is chassis ground and connected to the shield of the 3.5mm plug.(pins 3,5 and 7 may be wired together since they are all common.) pin 8 is not used in your case but normally there is 12v on it supplied by the AM9. Just leave it open. Make sure you use shielded cable for your signal wires. I would use a two conductor shielded cable for the data/12v turn on signal wire. Good luck.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 48
Registered: May-07
Kieron,

In reference to your display problem again, I looked at that posting of mine and it's really not very clear about what to look for so... if you have a CD5V console the cap in question is C19 and will be the leftmost cap on the top PC board. If you have a CD5V version 2 (V2 on the Model/serial number label, bottom of the CD) then the cap in question is C17 and is located on the bottom PC board.
 

New member
Username: Tomttom

Post Number: 2
Registered: Oct-07
Mark,

I have a 230V Powered AM20 and an M1 Multiroom Interface. Due to some unreliable contact we had to fix the interconnect cord between the two and the AM20 wouldn't power up any longer. I don't know if there's any coincidence. I opened the AM. Fuse was ok. I have an LCD remote called P1 Personal Music Center.

There's a 8 pin mini DIN plug on the MRI side and a 5 pin DIN on the AM side. According to some drawing the signals are: variable audio left/right, grounds and power on (+10V). It seems logical to suppose that when the 10V is present the subwoofer should power up. However we couldn't measure 10V on the corresponding pin.

The MRI somehow still senses the AM because the LCD can only be used if the AM is connected to the MRI. If I unplug the interconnect cable it starts searching and no control is possible.

I even tried to short the A1 and A2 legs of the triac but nothing happened.

Could you shed some light on how the two units sense eachother and which one of them could go wrong?

Any tips on how to proceed?

Thanks,

Tom
 

New member
Username: Jay757

Post Number: 1
Registered: Feb-08
having problems with my accoustimass 6 series II subwoofer ..aparantely 2 0f my sataelites are not working very well, sound comes out but not as loud as the other 3 when i swap the output plugs over to the other speakers, the adjacent speakers work like the other which is perfect... i suspect a internal problem in the sub module .....anyone have any solutions ...please help.......
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 49
Registered: May-07
Tom,

First and foremost, shorting the legs of the triac together is not a good idea. If you had an output problem ie. blown channel then you could have done some real damage. There is a safety feature that shuts down the power supply if there is a DC problem with any channel. As far as the turn on thing, you should have 10-12v on pin 1 of the din connector, AM20 side. (pin 6 on the MRI side) This is the initial turn on voltage for the AM20, after power up, the sub's own 12v supply keeps it on. I assume you are using one of the room outputs on the MRI to control the AM20. Since you have the cover off the AM20, make sure it's unplugged from mains power and check the continuity between the black lead and the white lead of the power transformer. Also check between black and orange. You should read very low impedance between the two. If you read a very hi impedance or open circuit then the transformer has an open internal fuse and will have to be replaced.
 

New member
Username: Tomttom

Post Number: 3
Registered: Oct-07
Mark,

There is about 5 Ohms between the white and black lead and 9 Ohms impedance between the orange and black leads of the power transformer. There's no 12V on the pin1 of the 5 pin DIN plug on the AM20 side.

It is interesting that the LCD remote (P1) sees the MRI until the cable is plugged in at both sides (MRI and AM20) regadless whether the AM12 is switched on or off.

Yes I am using the room A output of the MRI.

Can you provide a pin to pin connection list of the 8 pin mini DIN - 5 pin DIN cable? I'm afraid we might have mixed up some of the pins when resoldered it. As it is connected now the Power On GND is pin8 on the mini DIN and pin#4 on the 5 pin DIN. Is it OK?
The pins of the 5pin DIN are not numbered in a consecutive order but like this: 1,4,2,3,5 clockwise if you look at it from its backside.

Thanks,

Tom
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 50
Registered: May-07
Tom,
OK, for the 5-pin DIN connector, pins 2 and 4 are ground, pin 3 is left channel input, pin 5 is right channel input and pin 1 should be carrying the 12V turn on signal from the MRI. The 8 pin mini-DIN connections are pins 1 & 3 left output, pins 2 & 4 right output, pin 5 is "room sense" (this is how the MRI knows something is hooked up so this pin is probably tied to one of the ground lines and becomes common to signal ground when attached to the sub and in this manner is the "Rm sense" signal informing the MRI that the sub is connected), pin 6 is the turn-on voltage pin and should be connected to pin one on the other end, pin 7 is data going to the speaker but the AM20 uses no data to control it so this pin is probably not used, pins 8 and 9 or just 8 in your case is ground from the MRI. I don't have the actual wiring diagram for the cable but the above is the only thing that makes sense. Hope this helps.
 

New member
Username: Tomttom

Post Number: 4
Registered: Oct-07
Mark,

Thanks. The sub is alive again!!!

It seems that one of the grounds was not on the right pin.

Thanks again,

Tom
 

New member
Username: Huntbch

Post Number: 1
Registered: Feb-08
Mark,
I have 2 questions on my Bose Lifestyle 12 Series II set:

First, I got the display to work (again) by replacing a 47uf/35V cap on the left front side of the digital board (same cap a tech replaced before) - however the display is dim and I'm wondering if the original cap was a 100um/50v (which the other are that surround it). Would that be causing my display to be dim?

Second, my RF remote isn't working. I checked the remote out and even re-soldered the large inductor. There is current running across it so I'm thinking that the RF circuit in the media center may be bad. Can you tell me what to look for in the media center?

Thanks,
-Jeff
 

New member
Username: Packjack

Post Number: 1
Registered: Feb-08
Need help! My Bose acoustimass 25 subwoofer plays fine until I cut it off, next time it is turn on, no sound at all, I have to unplug the unit to reset it before it will play again, then it plays fine for as long as I don't turn it off. I have Bose lifestyle 12 series II system that is made up of Lifestyle model 5 music center and a Bose power Acoustimass 25 series II subwoofer. Need help in determing what is causing my problem, your help would be appreciate very much...
Thanks,
 

New member
Username: Huntbch

Post Number: 2
Registered: Feb-08
FYI... I called Bose tech service line and they are sending me a new remote (for free). They said to see if that works, but if it is still bad they offered to repair the unit (refurbish it entirely) for a flat fee of $165 - which would include a 1 year warranty.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 51
Registered: May-07
Jeff,
It's great that Bose offered to replace the remote but I'm also thinking that your problem might be an even simpler one. If the room code has been changed accidently in your console then the remote might be working but the console would not respond. Inside the remote where the batteries are, you will notice a block with a number of switches on it. These are used to change the room code for your console. This so you can have more than one system in close proximity and not have the remotes battling each other. Check your owner's manual for changing the room code on your console and see it that doesn't fix it. As far as the dim display, that will probably be more bad caps in the power supply and possibly a weak display tube. I'd say for $165 it might be worth having them simply overhaul the thing. Couldn't hurt!
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 52
Registered: May-07
Darnel,
With the symptoms you describe, I have to conclude that your problem lies within the protection circuitry of the subwoofer. The Acoustimass 25II has an elaborate protection system that can control muting of all the channels and/or the shutting down of the sub. If it was a "real" amp problem then you would not be able to turn it on even after unplugging and powering up again. I suspect that some component in part of this circuitry is leaky and only comes into play when you shut down the system from the console. The microprocessor sees an error, stores it and won't release the mutes. When you unplug the system of course everything is dumped and when the system is powered up again everything appears fine to the microprocessor... until you power it down again. This is NOT an easy fix unless you have the prints and are an experienced electronics technician.

The first test would be to verify that the sub is actually shutting completely off when you turn it off from the console. If it does NOT really shut off then the above theory is correct.

There is another possibility but it would be the first time I've ever heard of it manifesting in the manner you describe and that would be the crystal in the DSP (surround processing) circuitry. Normally this problem presents itself while the unit if playing and after X amount of time the sound quits. The fix for that is simply to replace the crystal but I doubt seriously if that's what is going on with your sub. I have responded to your email so be on the lookout for that.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 53
Registered: May-07
Darnel,
OK, I spoke too soon... I TRIED to respond to your email but it seems I need a digital signiture to do so??? What's up wi dat???
Do you have a 'normal' email address I can send the info to?
 

New member
Username: Olof

Post Number: 5
Registered: Jan-08
Hello Mark and of course everyone else! :-)

I'm about to buy a Lifestyle 12 from year 2000 and this lifestyle have the problem with a non working subwoofer. Is there anyway to know without opening the cabinet if it's the simple thing as the blown fuse?

The seller of course don't know about the fuse-problem with the lifestyles so I have a perfect buy situation here I think! :-)

What should I look for? Is the satellites working if the sub-fuse is blown? Isn't there any sound at all in the sub if the fuse is blown?

Could it be a bigger error? Could I be wasting my money?

Regards
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 54
Registered: May-07
Olof,
If your looking to buy a LS12 system then the first thing you need to find out is whether it's a LS12 I or an LS12 II. The first one has an AM9P as the subwoofer and the second an AM25II. If it's the LS12 II and I suspect it is because of the date, then the sub may have the age old "bad crystal" problem. If the sub is turning on but has no sound then that's probably what the malfunction is. If however the sub is an AM9P then it's a whole new ballgame. There are a variety of things that could be wrong with an AM9P. Do your homework and find out if your dealing with apples or oranges so to speak. I'd say short of some kind of catastrophic lightning failure (and depending on your initial cost outlay) you should come out on the winning end.
 

New member
Username: Olof

Post Number: 6
Registered: Jan-08
Hey Mark and thank you very much for your response!

The system is probably a LS12 II and according to the seller none of the satellites or the subwoofer is working. The seller spoke earlier to a bose-dealer and according to the dealer it's "problably" the amp's in the sub that's messed up (the dealer said this on the phone without checking it out) and according to the dealer it's around 500$ to fix.

It feels that the repair-shop will repair the amps for a $500 even if it's a fuse or a crystal that's blown, just for the simplicity (and cash).

My perfect situation would of course be to buy this and finding out for myself that is only a crystal or a fuse that needs a replace... :-)

Mark: Do you know about any other major errors that it could be (when the symptom with NO speakers at all working) that might make this kit totally worthless buying?

Im a bit confused about this, buy... not buy... buy... ? :-)

Thanks!
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 55
Registered: May-07
Olof,
If the subwoofer is not working then it follows that the sattelites wouldn't be functional either. I don't know where you live but $500 to fix a AM25II is astronomical if you ask me. I generally repaired them for less than half that, parts included. If it's truly lightning struck then it might be a bit higher but $500?

As far as other major errors, in a word... no, can't think of any. If you're getting a good deal then I would say your in good shape. If you make the purchase and it's not something simple then let me know and we'll figure out a way to get it going again.
 

New member
Username: Huntbch

Post Number: 3
Registered: Feb-08
Olof,
I posted earlier about Bose offering to fix my system for $165 flat rate - I contacted them again about this (as my new remote [they sent to me for free] did not fix my problem) and they said I can send in one component or the whole system and it will be totally refurbished for a flat rate of $165! Not bad - but you have to contact Bose directly and ship the system to them. Oh yea, they also back the refurb with a 1 year warranty... pretty impressed with their offer (especially after all the bad press I've read about Bose).

Anyway, just call Bose (number is on their website) and go over your options with them directly - they also can give you info on a trade-in allowance if you want to upgrade to a newer system.

Good luck,
-Jeff
 

New member
Username: Olof

Post Number: 7
Registered: Jan-08
Hello Mark and Jeff and thank you very much for your aswers! :-)

I made up my mind and decided to buy it! I have spoken to the seller and I will get the system in a couple of days.

It seems that the system plays for a short time than the sat and the sub disapears but I suppose I will have to find that out for myself.

Here is a picture of the system:
http://213.132.112.100/images/25/2598462643.jpg

I hope to get a litte bit of more help from you guys when I finally get the system! If I could I would bake a cake and mail it as a sign of my appreciation! (or maybe let my fiancé do it, would probably get better then)

Thanks once again!
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 56
Registered: May-07
Well there you go Olof and I'll paraphrase 'It seems that the system plays for a short time and then the sat and the sub disappears'. Absoluteley the classic symptoms of a failing CR400, the infamous "bad crystal". Looks like you'll be in good shape on this one.
 

New member
Username: Amoldc

Post Number: 3
Registered: Dec-07
Hi,
I am looking to help my friend convert a Bose AM6 Speaker package to 220V, which he bought in US and is moving to Europe now.
Appreciate if anyone can help me with this.
Thanks a lot in anticipation !!
 

New member
Username: Olof

Post Number: 8
Registered: Jan-08
Thanks Mark!

Now I finally got my hands on the system!

Unfortunately it seems like the sub is AM9P...

The prior owner had a really crappy repair-job on the input-cable (the 8-pin DIN-cable). I cant understand how he have connected this? It seems that:

top of 3,5mm is connected to pin 7
mid of the 3,5mm is connected to pin 3
base of the 3.5mm is connected to pin 6

ground on the rca:s is pin 5 and pin 2
Tip of rca:s is pin 4 and pin 1

Is this correct? (pinouts according to the "maleside" of this: http://freespace.virgin.net/tom.baldwin/DIN8-pinout.gif )

Feels that I have to start with checking all the cables before I start digging into the sub :-)

With best regards
Olof
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 57
Registered: May-07
Olof,
I will refer to the 3.5mm jack sections as "tip","middle" and "shield". The "tip" should be connected to pin 6, this carries serial data to the sub. The "middle" carries the 10-12v turn-on voltage to control the power on the sub and should connect to pin 1. The "shield" is ground and should be connected to pin 7

Pins 2 and 4 are the signal inputs for the Left and Right channels respectively. Pins 3 and 5 are the grounds for the two channels. A mixup of these two sets, 2&3 or 4&5 is no big deal because they drive a differential amp within the sub (and there is a "differential" regardless of which pin is ground and which is signal. The important ones are of course the ones for serial Data and turn-on voltage. Make sure they are correct. And by the way, the reference you found for the male 8-pin DIN connector is correct.
 

New member
Username: Olof

Post Number: 9
Registered: Jan-08
Hello Mark!

Thank you very much for your help in my system!

I opened the sub and found that the fuse was melted, so 1$ away and my system was up an runnning!! :-) :-)

I bet the recent owner would smack himself if he would hear about this!

Oh, one last question regarding the speakercables, I suppose that the tip of the RCA-connectors is to be connected to the + of the speakers? correct?

Thanks again for all the help!

regards olof
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 58
Registered: May-07
Olof,
Yes, connect the tip of the RCA's to the "+" of the speakers. You COULD hook them to the "-" as long as ALL the speakers are done the same way. By doing this you are assuring all the sound sources are in phase. With the little satellite speakers it's not so much a big deal but with normal full range speakers it would be but only from an acoustic standpoint, not electrical.
 

New member
Username: Clint204

Johannesburg, Gauteng South Africa

Post Number: 1
Registered: Mar-08
Hi Mark
Hope you can help me. I had my LS12 series 2 hit by lightning. The Bose Agent here in South Africa said my DSP and Amp board were fried and wanted to charge me about ZAR8,000 (Over $1000). I took the unit back and opened the bass module myself. Both boards seem fine with no apparent damage and all fuses intact. I checked the power supply (which seems to have been disconnected from the board)
It is both a 115V and 250V switchable unit.
I have voltage going in, but no power coming out of the power supply. I believe in a previous post you had the voltage that should come out of the power supply Blue outputs - 57VAC and Yellow Outputs 28VAC and grey as common.
Do i have it correct? Would it be possible to email me the schematics of the power supply?
Do you know where i could get a new power supply if this one is gone? Hope you or someone else on this forum can help

Many Thanks
Clint

Email: clinton.nean@aerialsonic.com
 

New member
Username: Clint204

Johannesburg, Gauteng South Africa

Post Number: 2
Registered: Mar-08
Hi Mark,

Sorry to bother you again. I have replaced the power transformer with one out of an old hi fi. I now get 60VAC and 30VAC out the blue and yellow outputs. Do i need they grey common wire? I am getting power to the subwoofer unit, however there is only a loud humming sound that comes out of the unit. The volume cannot be adjusted. Seeing as there is sound coming from all the speakers, i deduced that the Amp unit must be working.

Do you know what else could be the problem? Or what would normally go on the DSP board? Do you have part numbers and schematics for the AM25 II bass module?

I really appreciate your help.

Thanks
Clint
 

New member
Username: Ricardolozano

Post Number: 3
Registered: Jan-08
Hi again Mark, Finally i've repaired the Bose ps28ii subwoofer power supply problem and it worked excelent just for 5 minutes at a low volume. but(question) If the original mosfets are P9NB50FP and i've installed a P7NB60 mosfet, could this be a good reason that this sub worked about 5 minutes then the mosfets got shorted because there are 2 amperes less of the capacity of each one? do you recommend me to put the originals or a 10 amp mosfet@500 volts? note; when the mosfets got shorted they have a 10 ohm and 100 ohm resistors opened that i've already replaced.Help will be apreciated thanks 4 all.}
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 59
Registered: May-07
Ricardo,
The current rating of the two devices is really no big deal especially at low volumes but... and this is a BIG but (no pun intended) what you're dealing with is apples and oranges. By that I mean what you have installed in the power supply is an IGBT (insulated gate bipolar transistor) and what was originally in there were MOSFET's. The P7NB60 is NOT a MOSFET device. True it's used in some switchmode applications but the design of the power supply in the LS28 prohibits the use of these devices. It's no wonder the resistors went "poof". You need to replace the MOSFETs with equivalent parts of similar current and voltage ratings.
 

New member
Username: Fbazbo

Post Number: 1
Registered: Mar-08
I noticed someone had a PDF wiring diagram for the input cable for an acoustimass 15. Is there somewhere this can be downloaded from?
 

New member
Username: Ricardolozano

Post Number: 4
Registered: Jan-08
Hi again Mark, checking the part number I've posted to you, let me tell you that I wrote it wrong , the real transistor that was in place of the original it was a SSP7N60A which ITS REALLY A MOSFET and not a IGBT transistor, question; what could be the problem of this LS28 that it worked only for 5 mins? I've replaced now with 2 K2842 Mosfet's which supports 12 amperes and 500V each, with this ones would u think it will be ok instead of the original which drives 9Amps and 500V ? Note; This will be the second time i have to replace the L6598D high voltage oscilator which it blows each time the mosfets gets shorted .Please tell me an advice again Thanks again Mark
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 60
Registered: May-07
Ricardo,
As I tried to warn you in the very beginning, the switchmode supply in the LS28II is very complicated. The problems you are running into are not because of underated components. This type of supply is inherently stable and efficient. It runs at very low current unless the load demands a higher current output. What you are no doubt experiencing is a failure in the feedback and control portion of the supply. The output section could be loaded to the point that the supply will shut down but not burn up as in your case. Somewhere else in that supply you have components that are defective and until they are found and replaced you will continue to experience the failures you already have seen. Sorry to be the bearer of bad news.
 

New member
Username: Ricardolozano

Post Number: 5
Registered: Jan-08
Hi again Mark I need the value of the surface mount mosfet (Q103) of the PS28II subwoofer can you tell me the substitute of that little mosfet?? It reads me 98 ohms and viceversa from Drain-Gain pins

I've already changed the parts that I've mentioned before, pls send me the Q103 info cause in the schematicyou've sent me it only appears as a mosfet but with no number substitute, I think this little mosfet is the last problem I'm having with this Sub, thanks again Mark, and pls Help
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 61
Registered: May-07
Ricardo,
Unfortunately, the only reference I have for that mosfet is the Bose part number in the service manual. Without the actual device I have no way of knowing what it is. If I were servicing that sub I would simply have ordered the part from Bose using their part number. I can try to contact them and see if I can get a part number but I cannot make any promises as to what results I'll have. Give me a couple of days to find out what I can and I'll get back to you.
 

New member
Username: Amoldc

Post Number: 4
Registered: Dec-07
Hello Mark,

One of my friend has a Bose AM6 III and is travelling overseas where US Appliances wont work bcos they use 220V AC. Is there a easy way to convert the system to 220v? Your help is greatly appreciated.

Thanks a lot.
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 62
Registered: May-07
Amoldo,
There is no easy way to convert the AM6III to 220. There are some internal changes that have to be made but the crux of it is... you have to change the transformer! The 220/230V transformer Bose part number is 264870-001. If you can get in touch with Bose parts dept. through customer service, be sure and tell them it's for changing the system you have so it will operate overseas. I've heard tell that people inquiring get the "we have no such part number" routine when in fact it is in the manual. If you are able to get the transformer then post back and I'll fill you in on the internal changes that need to be made.
The other option to this of course is to get a sizable stepdown transformer and just put it between the incoming AC and the Bose.
 

New member
Username: Amoldc

Post Number: 5
Registered: Dec-07
Thanks a lot Mark. I had the same experience when I called Bose for the parts. I will let you know how it went when my friend calls Bose.

But hey thanks a lot. You the man !!

Amol
 

New member
Username: Amoldc

Post Number: 6
Registered: Dec-07
Hello Mark,

Good news is that we have ordered the part from Bose and its on the way. Can you please send me the instructions on how to convert the AM6 III to 220 V.

Thanks a lot.
Best Regards,
Amol
 

Bronze Member
Username: Mr3dzpop

Woodstock, Georgia USA

Post Number: 63
Registered: May-07
Amol,
Good to see that you were able to order the part. Now for the changes. On the main pc board, find T1. It's a small power transformer and on the secondary there are two resistors in place now. They are "0" ohm resistors (basicly jumpers)and are labled R3 and R7. Remove them and on the pads marked R2 and R6, install 130 ohm resistors. The pads are for installing chip resistors but you can use 1/4 watt wire lead resistors if you are unable to find the chip type. This mod is done so the rectified voltage from the transformer is the same as with the 120VAC configuration. That's all there is to it. Good luck.
P.S. I've sent the info to your gmail email address.
 

New member
Username: Amoldc

Post Number: 7
Registered: Dec-07
Thanks a lot Mark. I really appreciate your help. I will let you know how it goes with the conversion.
 

New member
Username: Ricardolozano

Post Number: 6
Registered: Jan-08
Hi Mark, Finally the PS 28 II works great! the only problem is when it works after an hour and heats to normal operation, the green flashing led changes to yellow flashing and returns to green color, in that interval of time the sound cuts of and gets back after 2 or 3 seconds and back again on and off, I am very sure that the Q103 MOSFET is the last problem it has, did u have now the value of that surface mount mosfet?, if not, can somebody here do me the favor to measure it with the voltimeter in the diode scale and tell me please how is measuring? That can be the biggest help somebody can give me, I just wanna be sure that it reads 98 ohms or not from Drain to Gain and viceversa (in the resistance scale) i think that mosfet is leaky, pls help me with that measurement

p.s who has this sub so he can give me that measurement? The Q103 is in the power sub supply and its near the big metal dissipator
its a surface mount little mosfet transistor with the K72 letters on it.

thanks alot.
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