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Sunfire True Subwoofer pops

 

New member
Username: Drdaveelect

Florida

Post Number: 2
Registered: Nov-09
We have a Sunfire subwoofer in for service. After replacement of many capacitors, the unit seems to work fine except for an occasional loud pop or thud from a normal audio source ,but with a steady low freq. test tone it work without any pops .Any ideas? Someone said it maybe switching intermittently in and out of standby on normal audio.We don't have any service info on this so it makes life even harder.
As always any help would be appreciated
 

Gold Member
Username: Jrbay

Livonia [Detroit area], Michigan USA

Post Number: 1028
Registered: Feb-08
Greetings Dave,

Can you recreate the problem? If it only happens at a low volume level then the auto on circuit is certainly one place to look. If the threshold is too high obvious problems could occur. The auto on should make a relatively distinctive sound and perhaps could be targeted or eliminated on that alone.

I am not sure how far you are into this and I may be tossing very elementary ideas out but if it isn't the auto on then I would check all grounds very carefully.
 

New member
Username: Drdaveelect

Florida

Post Number: 3
Registered: Nov-09
Thanks for your input Jim,

On an audio source I get the intermittent pop or thud noise more often on voice or when their is a break in the low frequency content. The level control does effect on how loud the pop is and when the control is all the way off ,no pops. Like I had mentioned with a low freq. test tone of any level no pops ever. When the unit goes into standby the LED is to go dim .If I kill the audio input it will time out and go dim. I'm not seeing that happen when it's playing.So i'm not sure if this a standby problem.
 

Gold Member
Username: Jrbay

Livonia [Detroit area], Michigan USA

Post Number: 1031
Registered: Feb-08
With that perhaps it is possible to put stand by/auto on aside. The next thing is the source as in can the noise be recreated with different sources?

If so, I would head back to the grounds and seeing if I could find ANY resistance anywhere. I may be way off base but my experience (mostly automotive) has been that low level noises such as these are some sort of bad/poor ground.
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 1
Registered: Mar-10
I have the same problem, and have just about finished reverse engineering the power amp board on my Sunfire true sub. I finally have found the components that set the timing for the auto on-off. Interestingly, most of the schematics are very similar to Bob Carver's original patent - but the auto on-off circuit is not in the patent (#5937074). I am not going to post Bob's schematics, as I feel that would be unfair - his patent has not expired yet. However, I can say that the auto on-off time is set by a single resistor-capacitor combination. R40 and C18. These are 5.2 megohms and 22uF. You will find these at the bottom-left corner of the quad jfet opamp U2 (MC34004). The 22uF cap looks to be a higher quality that all the other electrolytics.

Another interesting thing is that the most complex integrated circuit in the whole sub is an opamp. There are only opamps, comparators, and discrete transistors (fets and bipolars).

By the way - my negative13v rail turned out to be bad, giving roughly 8v DC, due to bad electrolytic caps - and this was throwing off the auto on-off threshold. I also blew out my pnp devices in the output stage, so just ordered some replacements.

Let me know if you have any additional questions, and I'll hopefully be able to point you in the right direction.
 

Platinum Member
Username: Nuck

Post Number: 14729
Registered: Dec-04
Welcome to the forum, port!
That's #1 opening post of the year!

most of us here don't get too technical, but you guys should be all set!

Dave, sorry I missed your OP.

Are the opamps replaceable port?
 

New member
Username: Drdaveelect

Florida

Post Number: 4
Registered: Nov-09
Port,

Thanks for the info. We did find a bad 1000 mfd. cap in one of the power supplies that we overlooked the first time around. All is well. Thanks again.
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 2
Registered: Mar-10
Yes, the opamps are just cheap motorola jfet quad opamps. There is nothing in the electronics that cost more than $2. Even the power npn & pnp devices.

A WORD OF WARNING though: anyone that opens up this sub - beware. The power supply caps on this board and on the back-plate can retain 100s of volts for literally days. You can get around a 300V shock. I only know this, of course, because I got shocked 2 days after it was last plugged in. Live and learn eh. I'm so used to working on 5v stuff.
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 3
Registered: Mar-10
I forgot to mention - if you want to completely disable the auto on/off, do this: pin 6 of U2 quad opamp is used as a comparator with some feedback hysteresis. The RC timer goes onto this pin. It looks like it gets charged to the negative 13v rail when in the 'on' state. Simply short it to pin 11 of U2 (-13v) and the sub should stay on permanently. To be safer, use a 10k resistor from pin 6 to pin 11. However, I have not tested this. Will update when I get the sub back together.
 

Gold Member
Username: Dmitchell

Ottawa, Ontario Canada

Post Number: 3731
Registered: Feb-07
Holy crap port, you know your stuff.
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 4
Registered: Mar-10
I am still waiting on new bipolar power transistors, but I did do a 1kohm load test on the -13v rail before and after replacing the electrolytic filtering caps. The old caps saw a voltage droop of around 3v with a 1k load, and the new caps show no noticeable droop. I also verified on an oscilloscope that the RC timer does indeed go to -13v and then slowly start charging up in the absense of an audio signal. So, to disable auto on/off, my previous post should still be correct. I also marked the caps that should be replaced. Might as well do all of them if you get in this far!
Upload
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 1
Registered: May-10
Hi
I have one of this beasts on my working table, I am preety frustrated. I have full (negative) voltage on the negative output transistors collectors, but only 13 volts on the positive collectors, I have replaced all fets. I guess that the malfunction is on the negative downconverter, and not in the upper downconverter. unfortunately the schematic I have is only close . I wonder if there are several versions... any hint will be deeply appreciated.

regards

Alex
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 5
Registered: Mar-10
Hi Alex,
Could you clarify what you mean by full negative voltage?
There are three sets of supply rails:
The low voltage rails: + 13v, -13v
The class D tracking rails: which are somewhere between the 13v and 160v,
And finally the bridge rectified and filtered line voltage, which I measured around +160v and -160v.
There is a 4 wire connector that has signal, gnd, -13v, +13v. You could check those first?
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 2
Registered: May-10
Hi, thank you for your input,
sorry for not being clear...
I have checked the low voltages supplies (+/- 13v) they are OK
on the source of the negative IRFS's I have -140 volts, on the source of the positive IRF's I have 13 volts.
I the schematic I have , as I mentioned is not of the one unit I have, instead of the quad LM339 (in the downconverter sections) I have an A211 optocuipler which is driven by a BA10393 comparator.
As far as I got, is to determine that I have a high frequency oscillation on the output of one of the BA10393 sections (in pin 7 that goes to the diode's optocoupler, which is pin 2), that is in the positive side, but on the negative side (that is output pin #1 of the comparator), there is no such oscillation , I will be replacing this chip.
I have replaced the small TO92 transistors(whose diferential output drives the IRFS's) they were leaky.(on the negative side).
any comentaire will be appreciated.
(forgot to mention, I am troubleshooting the unit with a lowered AC voltage, something around 90 volts)
thanks again
regards

Alex
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 6
Registered: Mar-10
Hi Alex,
I will dig up the reverse-engineered schematics tomorrow as I left them at work. As I recall though, the high power output fets( nmos for both rails) connect to the bridge rectifier rails via a couple of fuses that actually look like resistors, and are soldered onto the board- not removable. When the fets blow up, they usually short circuit, hence the fuses. There are a couple of replaceable fuses on the power amp board too - one for each high v rail, but I assuming you've checked those.
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 3
Registered: May-10
Hi,
Thanks again... there are a pair of jumpers on the location you mention that there are fuses like resistors, I put a pair of 10 ohm 1/4 resistors instead (underneath meanwhile), maybe they are too high, but I already blowed a pir of OPT...

thank you for your support
regards

AlexUpload
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 7
Registered: Mar-10
Yes, those are the ones: JP1and JP2.
10 ohms is much too high. The bipolar class D transistors can run at over 20 amps, so these need to be down in the milli ohms. I blew both mine too, so I do not know what their exact values need to be, but assuming a 1v drop at full power gives 0.05 ohms. The 4 diode string that biases the class AB output stage can also get blown out, leading to further destructive powers!
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 8
Registered: Mar-10
Hi Alex,

Both positive and negative class D power rails are formed by a couple of buck regulators, and both use nmos power fets. This means that the source sides of the powerfets are different: the source of the positive rail will be the switching node of the buck, and if it is inactive, it will be a low voltage like +13v. However, the drain side of this fet should be 140v. For the negative rail, the source side will be -140v, and the drain side will be a lower -13v or even -6v. Bob Carver is able to use nmos devices for both rails as he is 'boot-strapping' 'flying capacitors' to provide isolate gate drive for each rail, and opto-coupling the drive signals to eliminate the dc-coupling problem.

Anyhow, check the drain and sources - they will be inverted voltages and drain-source swapped for each of the two rails.
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 4
Registered: May-10
Hi
thanks for your input,
I am trying to solve why I have -140 on the negative collectors on the (2SA2121) output transistors , which according what you tell me should be somewhere around -10 volts.

i checked the drain and source (respectively) and they are OK, +140 and -140

I am still waiting for the BA10393 to replace...

does your schematic have 2 BA10393 or 1 LM339 on this section ?

thanx again !!

Alex
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 9
Registered: Mar-10
Hi Alex,
I am unable to output from my computer, so had to take a photo of the screen. Here is the output stage transistors:
Upload
when I get a proper file, I will upload it.
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 5
Registered: May-10
Hi
Thanx for taking the time to make a picture of the screen !!!
It seems that the schematic you have is closer to the unit I have :
the schematic I have looks like this:

Upload

it would be easier if I send you the schematic I have , so I can pinpoint where the differences are, or if you agree to send me yours...

my email is alex..rubli.net (replace .. with you know what)

I can't thank you enough for the help, sunfire stopped me responding after sending me the schematic , which is not the revision I have

best regards

Alex
 

New member
Username: Port3f8

Los Gatos, CA USA

Post Number: 10
Registered: Mar-10
Yours looks closer to their patent app- with a 3 diode bias string. Mine has 4 n4148 diodes. Our computer tech guys are out today- as soon as I can connect my unix box, I'll get you a better, larger schematic.
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 6
Registered: May-10
Hi
I am still lost, I changed the suspicious BA10393, but I don't see any high frequency comming out from either output of the chip. I can't do more without its shematic, as I said, I have anoher version of it
help...

regards
 

New member
Username: Dlatham

Post Number: 1
Registered: Jun-10
I am working on a Sunfire True Subwoofer I've replaced a bunch of caps and it seems to be working ok but I get a LOUD pop when I unplug it. It seems to be coming from the tone control board and not the power amp board. Any ideas? Also I got a schematic from sunfire they were willing to give it to me because they no longer service this model, so it might be worth asking them for one.

Thanks
 

New member
Username: Vette45

Post Number: 1
Registered: Mar-11
Dave P,
Looks like I have the exact same problem as yours with my True Subwoofer. i.e. the unit works as normal when the volume is crank all the way up. But when the input signal gets low or if the sub volume is turned down, then the unit will make loud pop until steady high volume sets in again. So did you resolve your problem? If so, can you please share your solution?

Port3f8,
After reading your replies, it seems like you really know the amp circuit of this subwoofer inside out. Can you please advise on how to repair this unit for my condition? Should I replace those 6 cap as mentioned in your post #4 above, will that solve my problem? BTW, can I get those components from local Fry's? If not, where can I get those locally?(I'm local in the Bay Area as well).

Can't wait to get the subwoofer fixed. Thanks for your help in advance.
 

New member
Username: Drdaveelect

Florida

Post Number: 5
Registered: Nov-09
I think all my problems were solved by replacement of caps in the +/- 12 Volt supplies. I think C-18 was one of the caps that made a difference.
It has been a long time since I serviced that Sub ,and hope it's my last.
I'm sorry I don't have more for you on this. Any good parts house should have the caps. If not you could order from MCM electronics. Good luck!
 

New member
Username: Vette45

Post Number: 2
Registered: Mar-11
Hi Dave,

Just want to confirm with you on which caps that you have replaced to get the unit working again. So did you just replace those 6 as labeled as "bad cap" in the picture from Port3f8 in his post number 4? Plus C-18 that you've mentioned?

Thanks.
 

New member
Username: Drdaveelect

Florida

Post Number: 6
Registered: Nov-09
Like I said It has been a long time since I serviced that Sub .To be safe Replace C-16, C-18 and the six that someone else had mentioned. Good luck.
 

New member
Username: Kerebrosalpha

Post Number: 1
Registered: Apr-11
I have some really big problems with my Sub woofer. It originally was giving burps in the sound. now the sub doesn't properly work. it only moves forward and is very distorted with no bass and blows the on board protectors in the process. the internal fuses are for some reason 10 amp Slo-blo instead of 10 amp fast acting. Also, the JP1 and JP2 aren't blown. Any idea what causing this issue. I'll try to post an oscilloscope view of what the output looks like on a 100 - 5 hz sweep.
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 7
Registered: May-10
good luck ! there is no troubleshooting guide I could give, there are two different "grounds" this is the fist thing you have to understand. there are some caps that go bad,(already mentioned here) , in my case, some optocouplers (HCPL-2611 )that aslo got bad, that are listed as op amps in some variations of this schematic of this sub. (I relapced them with 6N137) hope this helps..send me a PM and I can send you my version of the schematic (which by the way did not correspond to the unit I had...
 

New member
Username: Kerebrosalpha

Post Number: 2
Registered: Apr-11
HOLY CRAP. I found Coil L1 was broken at one end so i soldered it back on. the moment i plugged it in, the thing made A VERY LOUD POP. Also, the main 10 amp Slo-Blo fuse on the outside now looks like this. Upload
 

New member
Username: Kerebrosalpha

Post Number: 3
Registered: Apr-11
The FPI4020 Bridge rectifier(200 volt, 40 amp) was blown...no current...Forward and backward on all poles.Upload
I'm heading out to get some new ones tomarrow. also, i'm going to check c-16, c-18 and other caps for possible damage. should i bother checking the transistors for problems?Upload
this was my repair on L1...Yeah for real.
 

New member
Username: Kerebrosalpha

Post Number: 4
Registered: Apr-11
replaced that Bridge rectifier. Didn't go over so well. We were stupid enough to plug it in and the Power transistor 2SA1302 Died.Upload
I'll be replacing all the Transistors on this unit in the next couple of days.
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 8
Registered: May-10
check also the hexfets....
 

New member
Username: Kerebrosalpha

Post Number: 5
Registered: Apr-11
Which are those? I'm replacing ALL transistors. Should i worry about the LM's?(8 pin IC's)
 

New member
Username: Rubli

,, Mexico DF MEXICO

Post Number: 9
Registered: May-10
according to my schematic and the unit I repaired, there are 6 TO220 IRF640 transistors, that might be a good idea to check'em out

good luck
 

New member
Username: Jlnorie2

Oak Park, IL USA

Post Number: 1
Registered: May-11
What a great resource this is!

Just wanted to report that I followed port3f8's advice on how to disable the auto on/off by shorting two pins on the 'U2 quad opamp' - using a 10k resistor (posted on March 15th & 19th)... And it worked like a charm!

My unit would start 'clicking' whenever there was no low frequency signal going into it; the clicking would stop as soon as the signal returned but once the unit had been on and working - the clicking would continue even if all other components had been turned off; and even if I disconnected the signal cable!. Since the MKII doesn't have an on/off switch/button, I would have to disconnect the power to make it stop...

After following the procedure described by port3f8 the unit is now working as it should and shaking the paint off my walls! Of course, now the unit is always 'ON' but I decided to use a cheap monster power distributor which I can turn off when I'm through using the Sunfire...

Thanks for your invaluable advice!
 

New member
Username: Kerebrosalpha

Post Number: 6
Registered: Apr-11
Oh yeah, should i replace the U2 Quad OPamp or leave it. Cause we can't get parts till our supply center gets the shipment of parts we put in.
 

New member
Username: Gxt6551

Post Number: 1
Registered: Oct-11
Hey, I am new here. I hope someone could help me out! I got a sunfire EQ 12 true signature subwoofer from Craigslist. It worked great at beginning. However, the issue is auto off. It will turn off after a few minutes no matter for movies or music. The led light is off completely. I need wait about 15 minutes then can switch it on. Is there anyone with the similar issue? I try to disable the auto off function as port3f8 said in this thread, but I could not found the U2 quad opamp as showed in the picture. Does sunfire EQ 12 have the different power amp board as the true sub discussed in the thread? Please help out? Thank you so much!
 

New member
Username: Ksdehoff

Post Number: 1
Registered: Jan-13
Port3F8 are you out there!

I've just come across this post and am deep into the repair - in addition to the 4 caps at c37-c40 being bad (all of them) and C18, I've also got a 21 ohm 2 watt resistor at R8 bad (visible signs of a burn. My symptom is that the sub pops when it transitions soft to loud.

I've got a cap tester and am wondering if I need to look at anything beyond the caps pointed out in this article.
 

New member
Username: Nathaniel

Post Number: 1
Registered: Mar-13
Hello,

I'm new to this board and I'm a novice in board component repair.

I have one of these subs and last month the sub just started to make an audio poping sound over and over even with the audio cables removed. Then both fuses blew blew on the board.

I replaced the 6 caps (shown on this thread) and the board fuses and then when i plugged it in the main fuse blew. I replaced the bridge rectifier and the main fuse. But I then when I plugged it in this time, with the board were I can see the circuitry, I could see that a mosfet had sparked. The GFI outlet tripped but the main and 2 board fuses didn't blow this time. I removed the bracket and 4 of the 6 mosfets are cracked and the one was a bit toasty. Any idea what would have caused these to blow? Nothing else looks blown/ burnt on the board.

The 6 mosfets are SEC 711 IRF640 but I don't know if it's an N or P well. Do you all know? I found some on ebay but I'm not sure if these will work. http://www.ebay.com/itm/IRF640-TO-220-Mosfet-10pcs-/400044471669

Thanks for any help
Nathaniel
 

Gold Member
Username: Magfan

USA

Post Number: 3024
Registered: Oct-07
Go to the IR website and enter the data and you'll get more information than you need....or probably want. But it WILL tell you if the device in question is nchannel or pchannel.

IR has a MAJOR plant in Temecula, California which is PROBABLY where the device was manufacturered....and packaged down south in TiJuana.

PS: the IRF640 is an Nchannel device. This is a commodity device not worth more than 1.10$ per thru something like DigiKey.
 

New member
Username: Nathaniel

Post Number: 2
Registered: Mar-13
I'm sorry what website?
 

Gold Member
Username: Magfan

USA

Post Number: 3026
Registered: Oct-07
IR = International Rectifier........they make the part in question.
Also, I believe that this is a legacy part which was SOLD to Vishay....so they made a bunch before production ceased.... It's called a 'build out'.
I suspect it is an 'obsolete' device and is no longer made by 'primes'.

They will be available for several years....or longer....yet to come....

Vishay and IR had an agreement for a couple years in which certain technologies and designs were transferred to Vishay.
 

New member
Username: Nathaniel

Post Number: 3
Registered: Mar-13
So is there no other mosfets I can replace them with?

I know I need 6 TO220 IRF640 transistors but I don't know the rest of the specs, if it's an N or P channel and the voltage and amps.

Can anyone provide a link to the part on http://www.mouser.com/ ?

Thanks
 

New member
Username: Revert

Post Number: 1
Registered: Jun-13
Great thread.

Years ago when these first came out I was the guy in MN who would have to send these in for repair. Back then no one could work on them, I was a service tech, but I had to send all amp modules back to the factory.

Now I finally got my hands on one to repair. This was an Architectural series Truesub. Customer said it would cut in and out. He must not have been too attentive, because this thing had a huge hum and was only processing part of the input signal. Right away it sounded like a capacitor issue to me, and so it was. I replaced the two 2200uF 25V caps on the power supply and the unit no longer has a hum, and is pounding away in my living room. Now I just don't want to give the repaired unit back... :-(
 

Gold Member
Username: Magfan

USA

Post Number: 3045
Registered: Oct-07
IR = International Rectifier.

http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXqsuu.pdf

Part is Nchannel MOSFET. and it Does appear to have been transferred to Vishay...but they will be equivalent part.
 

New member
Username: Revert

Post Number: 2
Registered: Jun-13
I was just able to acquire one of these for my very own after drooling over them for 15 years.
I bought it for $200, because the unit had the normal 60 cycle hum. Nor problem I thought, replace the 220 uF and the 1000 uF caps and I'm all set. Opened it up, caps looked fin.e, replaced them anyways, and still had the hum. Took it apart again and took a closer look. I forgot exactly, but I think it was C13, 470 uF 25V caps right next to a voltage regulator on the signal input board. Replaced one, sealed it back up, and now I've got it pounding away in my living room as I type this. No hum.

So there you go guys, if you have issues with these, replace the low voltage filter caps too, @ $0.80 it's not a bad idea.
 

New member
Username: Audiorep1013ns

Richmond, VA USA

Post Number: 1
Registered: Oct-13
I need a big favor from, I have a Sunfire TS-SJ8 Subwoofer. I removed the 2 big Transistors 2SAxxxx and 2SCxxxx PNP & NPN transistors and I don't remember which one goes where the location # is Q7 and Q11. If someone knows where I can find the schematics I would appreciate it. Thank you so much
 

New member
Username: Kerebrosalpha

Post Number: 7
Registered: Apr-11
Hello, I have a TrueSubwoofer, REV A board. Look at my pics above, mine goes left to right 2SA 2SA 2SC 2SC
 

New member
Username: Bondjbond

Post Number: 1
Registered: Oct-13
Hello everyone, I have exactly the same situation described by Nathaneil in his post at 03/25/13. I have replaced 6 bad Caps and blown fuses, after I plugged it in, the third MOSFET from the left blew up, the fuses did not. Could anybody help with what causes this and what would I should be looking to replace to fix this issue. Any help will be greatly appreciated. Thank you.
 

New member
Username: Kerebrosalpha

Post Number: 8
Registered: Apr-11
I gave up on mine finally. You might as well too. I took it to 5 repair shops, all of them said they could do it, and gave me a call back 2 months later saying they gave up too, and i would be better off just plating the side and using it passively.

To directly answer your question, no one really knows what causes the issue you described. For us, there's 6 smaller transistors that were all blown on the other heat sink. IRF640 I think. Then the 3 small transistors near the power transistors. But hell, I'd like to see you try fixing it. I've had this thing for 3 years, and over 2 years, i couldn't do it. Only reason I gave up is i ran out of spare parts in my parts bins.
 

New member
Username: Revert

Post Number: 3
Registered: Jun-13
I may be interested in buying the dead ones off of you guys if the price is right. Shipping cost might suck, but if they're just collecting dust from now on I'd like to have them around. Let me know.
 

New member
Username: Bondjbond

Post Number: 2
Registered: Oct-13
Dear Kerebros, thank you for your thoughts
on the subject. I have ordered MOSFET's,
rectifier and will give it one more shot.
If this does not work I may follow up
your steps, but this is just a matter
of being persistant and make god gamn
thing work. Sincerely,
 

Gold Member
Username: Magfan

USA

Post Number: 3104
Registered: Oct-07
http://www.vishay.com/docs/91036/91036.pdf

Link to data sheet for IRF640�..Now, as I said before, made by Vishay.
This is a COMMODITY part and should be inexpensive if not downright cheap
 

New member
Username: Kerebrosalpha

Post Number: 9
Registered: Apr-11
I gave Up on my Sunfire. I plated the side and made it a passive sub. Made a home made Class A low FREQ Cube amp(about the size of a 8x8x8 box), rated at 400watts at 4 ohms single channel with <.005THD and high dampening factor. So far, it's running really well, and tbh, i think it's responding better below 35hz than the stock amp. However this thing needs tweaking. Might try and repair my sunfire's amp one more time, but the board has so many blown traces and what not, i have more wire than trace now.
 

New member
Username: Nava

บางใหญ่, Nonthaburi -... Thailand

Post Number: 1
Registered: Aug-14
Hi
I have the Sunfire subwoofer mk II in for service too, a symptom was the unit have no sound. I found the power transistors and mosfet were shorted, I replaced 4pcs power transistors and 6 pcs mosfet but still not work. Can anyone suggest me.

Thank you
 

New member
Username: Nathaniel

Post Number: 4
Registered: Mar-13
Sunfire is crap! After my attempt in fixing this over priced piece of $hitt and spending $60+ in parts it still wouldn't work. I threw mine in the trash where it belongs.
 

New member
Username: Nava

บางใหญ่, Nonthaburi -... Thailand

Post Number: 2
Registered: Aug-14
I forgot to mention the unit has DC voltage at output of power amplifier about 35Vdc when plug in the ac cord. Also I measured the 140V power supply, +140V dischared faster than -140V.
 

New member
Username: Hecklerz

Post Number: 1
Registered: Mar-15
Hello,

Anyone have some advice on repairing a Sunfire TS-EQ10 that powers up fine, no blown fuses, but no sound output.

It shooshes when I power it on and everything seems fine but no matter what signal I put into it I get no output whatsoever. When I touch the RCA to the input I do get that hum.

!!!!!!Please advise!!!!!!
 

New member
Username: Audiodoctorcanada

Post Number: 1
Registered: Mar-15
I repair and will buy defective units that have not had failed repair attempts. (Its easy on these to make the damage worse attempting repairs to downtracker)

drop me a line s_vares@hotmail.com
 

New member
Username: Munchkinsandwich2

Post Number: 2
Registered: Mar-15
Hi everyone,


Thanks for the info. We find a bad 1000 Ic.
cap in one of the power supplies that we
overlooked the first time around. All is well. Thanks again.
 

New member
Username: Brainee

Post Number: 1
Registered: Jul-15
Hi guys.
I'm desperately seeking help to fix my Sunfire D-10
subwoofer. Bought it second hand, opened it and
found out that C13 and R3 are burned. Subwoofer is
working but I'm afraid that it might cause some
problems later on. Does anybody have a schematic? Or at least any idea how to fix this.
 

New member
Username: Kevc711

Post Number: 1
Registered: Nov-15
Hello everyone,
Hopefully this thread is still active. I recently purchased a Sunfire True Sub MK iv. I am replacing the power caps (200v 1600uf) but I can not at all remember or find where the jumper wires go to. Can anyone at all either tell me where they go or upload an image of where they go? All the ones I find online are overhead shots that don't help at all. Thanks so much!
 

New member
Username: Tonebells

FL

Post Number: 1
Registered: Mar-17
https://www.ecoustics.com/electronics/forum/home-audio/618938.html#POST1861785

JP1/JP2 are 0 ohm resistors.
 

New member
Username: Scrotor

West Sacramento, Ca United States

Post Number: 1
Registered: Jun-17
Greetings all!

So a friend brought one of these sunfires to me to look over an if possible repair. They stated no power. First thing that caught my eye was 4 caps mentioned in this thread, the tops were bulging. After replacing, still no power. I then ohm out infinity on the fuse holder and noticed the fuse cap never engages when rotating - bad fuse holder replace. power restored.

PRIMARY QUESTION: When doing a test on each left and right channel separately, i get a lower amplitude output when testing just the right channel. Left is greater in amplitude however.
When reading the manual, it states that if using only a mono input, use the Left channel, and bridge the right.... leading me to wonder if the lower output from just inputting to the right channel only is normal?
 

New member
Username: Ranman57

Post Number: 1
Registered: Feb-18
Hi All!

I just thought I'd throw this out there for anyone who wants to try out the trigger bypass concept.

I recently brought my Mark IV out of retirement to use in my office as it seemed silly to just let it sit in the basement doing nadda. Due to the wiring in my office being part of a whole house audio system I need to run it from the speaker level inputs. The problem was since I rarely play the audio in there very loud the thing only turned on sporadically at best. So I tried the bypass with a 10K resistor and confirmed that works great. I then went looking for a relay to use as a 12 volt trigger and found the CZH-LABS Electronics-Salon 1PCS Dual SPST-NO 10Amp Power Relay Module, AC/DC 12V Control Voltage on Amazon as I wanted a sealed relay that could take the pounding inside the sub's cabinet.

Here's where it gets kinda fun. When I went looking for a good place to mount it I noticed two screws in the middle of the plate that in my rev of the amp don't do anything, they must have been put there for some other future purpose or whatever. As it happened they match the mounting holes on the relay exactly, and with a little pushing around of wires the relay fits in there like it's factory installed. I used a 5.5mm panel mount power jack to get power to the relay as I couldn't find a sealed back 3.5 phone jack that seemed sturdy enough.

So in the end it all works great. The sub's on its second recapping at this point, and will surely need it again some day, but for now it's a great addition to the office setup. I hope this helps anyone who wants to manually control their sub...
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