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Troubleshooting Reel-To-Reel

 

Bronze Member
Username: Dscrobe

Reading, PA USA

Post Number: 74
Registered: Dec-05
I know its a museum, but I got one for free and would like to tinker with it before I pitch it. It's an AKAI M-10 reel-to-reel player. All moving parts work but no sound is coming out. Someone told me a signal tracer is a good tool to use. I could see if there is signal at the tape head. Anyone know where to get a tracer?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11814
Registered: May-04
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If the meters respond to a recorded tape, there is signal coming from the playback head. If the meters don't respond when in "record" mode, there are serious problems.
 

Bronze Member
Username: Dscrobe

Reading, PA USA

Post Number: 75
Registered: Dec-05
The meters do not respond when playing a recorded tape. However, I did not attempt to record yet. That would be my next step.
 

Gold Member
Username: Nuck

Post Number: 9368
Registered: Dec-04
The meters didn't even move a bump?
Do try an input to it, the recording heads might still work, but without outputs, it will sound like a tree falling in the forest with no-one around.
A signal tracer is useful, but does not replace a good meter.
If you are so inclined, get to reading the power supply and it's associated protection bits, there are not many.
The Ampex units I have fixed are different from the Akai, but that R2R is a reasonable unit, if you can find the tapes for it.
 

Bronze Member
Username: Dscrobe

Reading, PA USA

Post Number: 76
Registered: Dec-05
Nuck, both meters did not move even the slightest. The original owner gave me some original recordings and some home made recordings. He showed me how to use it, so it can't be operator error. I am assuming the meters respond to a signal going to the recording head and a signal coming from the playback head. If the meters move at recording, do I assume that I have a bad playback head? As far as reading the power supply and protection bits, I'm not sure where to check this. The power indicator lamp comes on and all moving parts work, so the power is making its way in. I am assuming that there is some DC conversion somewhere, and not sure where this might be.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11815
Registered: May-04
.

Does the deck have a headphone output? If so, plug in some phones. If you hear nothing when you are in "record" mode, the problems have just taken another step up the credit limit.
 

Gold Member
Username: Nuck

Post Number: 9373
Registered: Dec-04
Good call JV.
 

Bronze Member
Username: Dscrobe

Reading, PA USA

Post Number: 77
Registered: Dec-05
There are two jacks for "MIC" and two jacks for "PHONE" at the bottom. I am not sure why there would be two separate phone jacks. Jan, do I try to input a signal and record onto a blank tape and try to listen with headphone jacks?
 

Gold Member
Username: Nuck

Post Number: 9374
Registered: Dec-04
ds, the stereo inputs for mic are just that. The dual phone outs are for 2 to listen together.
Very common.
If you have a mic or 2, go ahead and plug them in, you needent record to pickup the signal, just rec and pause.
 

Bronze Member
Username: Dscrobe

Reading, PA USA

Post Number: 78
Registered: Dec-05
Ok, after going home from work and taking the thing apart, banging it, looking at it and putting it back together, I got sound out of it but only on the right speaker with a lot of crackling sounds. No sound at all comes out of left speaker. I had the volume control for the right all the way up. It didn't get that loud, but the crackling was very annoying. Both meters still did not move at all.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11817
Registered: May-04
.


How much effort is this thing worth? Does it have Dolby B noise reduction? 15 i.p.s. speed? Most people want a reel to reel to watch the reels go 'round. There is nothing magic in a mid priced consumer R to R machine. A $79 stereo HiFi VCR makes a better recording with longer playing times. Put on a CD and hit play on the Akai then pretend you're listening to a Studer, Revox or Tandberg top o' the line machine.


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Bronze Member
Username: Dscrobe

Reading, PA USA

Post Number: 79
Registered: Dec-05
I wouldn't want to spend any money at all on this thing. It's more of an antique item. It's just nice to have it working also. I thought it would be something quick that could be fixed. But from my observations, looks like its ready to be scrapped.
 

New member
Username: Mgarnel

CascaisPortugal

Post Number: 1
Registered: Aug-16
I experienced the same problem on an AKAI 1721W. I used half a can of Contact Cleaner on the volume potentiometers (which also work as rec level control), turning the knobs completely in both directions and got both channels to work fine.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18244
Registered: May-04
.

I can't remember how many components came into the repair shop with controls (and subsequent circuits) which had been effectively drowned by a half a can of contact cleaner. This is a bit like the automotive engine with starting problems. Pouring a half a can of starter fluid down the carb is not a good idea.


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New member
Username: Mgarnel

CascaisPortugal

Post Number: 2
Registered: Aug-16
Jan, I see your point... I just got lucky, I guess.

Another akai that i have, a 1720, plays just fine but when I try to rec, i get nothing on the right channel and a loud cyclic thump on the left.
It was working fine about a month ago, then it started to peak the rec level (it was recording normally and suddently the vu level peaked to the end of the red area like it was maxed out) and about a week later, it stopped getting any signal.

Do you have any insights on what i should look into?

Thanks in advance,

MG
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18245
Registered: May-04
.

Do you have a schematic?

Do you know how to read a schematic?
 

New member
Username: Mgarnel

CascaisPortugal

Post Number: 3
Registered: Aug-16
I have the schematic for the 1721W/L but I read somewhere that they are the same between the 172* series, so it should work fine for the 1720. (aside the front panel, they do look like twin machines)

I can sort of read a schematic. I mean, I can understand and identify the individual components but I'm not too keen on knowing their function as a circuit.

The image is to big to send it here and when I try to shrink it dowm, it looses legilibity... Can I send it by email?

Best regards,

MG
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18246
Registered: May-04
.

There's no point in sending the schematic. I don't have time to go through a troubleshooting process on an old Akai and a forum is not set up for that sort of work.

I would first send you to my previous comment in this thread; https://www.ecoustics.com/electronics/forum/home-audio/410904.html#POST1340818

Next, I would ask you to read this;
https://www.ecoustics.com/electronics/forum/home-audio/729585.html#POST2044116

You have a schematic, you need to learn how to read it and follow the flow of a circuit.

Then you'll need a DVOM for measuring signal and Voltage flow, a signal generator and an oscilloscope. Plus some amplification and speakers to listen through. You'll need more gear but we'll get to that in a minute.

You'll need to identify the various circuits inside the player so you know what you are inspecting. Input, output, power supply, eq, etc.

You will most definitely need to know where to place the probes of your DVOM so you don't blow up the circuit or possibly electrocute yourself.

Don't take that last bit lightly, electrocution is always possible when you are sticking your hands inside a component with 120 VAC powering through it.

Then you will need a space where the deck can be disassembled and laid out for how ever long it takes to locate the problem components and have them shipped to you for installation. If you are unsure of how to troubleshoot a circuit, then you'll probably blow up a few parts before you get it right.

It's a fair assumption the unit was defective before it was put on sale. Old stuff is almost never in good shape.

Even if it was in perfect operational shape at the time, thirty and forty year old components have parts which have drifted or simply gone bad. Capacitors used during this time period will mostly need to be replaced due to age.

If they have leaked or dried out - which is the most common situation with such gear - they will have allowed unwanted Voltage, quite possibly DC, through to more sensitive circuitry.

This is where you really need to be a good tech because, as I mentioned in the one thread, it is most often parts which have gone wrong in front of a damaged component which need to be located and replaced unless you want to continually replace good parts with more new parts due to the improper Voltage/Amperage they are being fed.

One of the most common mistakes people will make with "vintage gear" is to plug it directly into a 120 VAC outlet and allow full Voltage to hit the bad caps. Vintage gear - and most especially vintage gear which has been sitting in storage - must be brought up to operational Voltages slowly and under controlled conditions.

This is normally done by plugging the the component into a Variac and watching its current draw on a scope. If you simply slammed this deck with full power from the wall outlet, you probably did damage to the component.


"It was working fine about a month ago, then it started to peak the rec level (it was recording normally and suddently the vu level peaked to the end of the red area like it was maxed out) and about a week later, it stopped getting any signal."


This is the typical timeline for a piece of old gear. It has sat unused for years and you plug it directly into a 120VAC outlet and throw the power switch. It works time for a week or so and then the defective parts begin to take their toll. When you don't realize the problem, you continue to slam the circuits with 120 Volts. You do more and more damage each time you do so. Where you first had one problem, you now have multiple problems of your own making.


It would appear, just looking at what you have posted, that the filter caps in the power supply will need replacement. From there you would need to isolate each functional circuit of the deck and troubleshoot for problems.

Tape decks have mechanical parts which wear out and will need replacement. Rubber parts like pinch rollers and belts are very susceptible to age. If you can't find a new rubber part, you're screwed.

Heads wear out and there's very little chance there are new heads available for this deck. Even if they were, it is a rather tedious procedure to install and properly align heads on a tape deck. Since you are dealing with small fractions of a degree in getting it right or wrong, if you don't have the right alignment tapes and the equipment required for the job, the best you can hope for is poor performance.

Just the test equipment needed for this job should run you at the most optimistic estimate a few hundred dollars. That's before you order any actual parts for the deck. Expect to pay at least $500-700 to get this deck up and running. And, for what?



There aren't many pre-recorded tapes to play back and not many new blank tapes to buy so, what's the point? As I said in the linked to post, if the deck didn't have the OEM specs to make it worthwhile restoring, why bother? This Akai deck was not great gear when it was new. If this were a Revox or a Tandberg, that might get you a different response about fixing it. As is, you will have a mediocre piece of equipment no matter what you do.

Put the deck on your shelf as a display and that's the best you can hope for in most of these situations. What would you be recording anyway? If you are recording from another source, most every modern source other than AM radio will have higher fidelity than this tape deck. So, what's the point?

You won't have extended playing time. You will have more noise and less frequency response. And far less convenience when it comes to actually listening to music.

If you want to record live music performances, then you are looking at much greater expense and hassle when a $100 portable digital recorder with built in mics will far exceed the performance of this deck and be much more convenient to set up and use and edit and transfer to new sources.

IMO restoring old, low end tape decks is not a good bet. If, however, you want to try with this deck, you'll need a lot more equipment and a lot more knowledge.

The very first thing to do is to look at the schematic and locate any integrated circuits or transistors in the deck which are no longer available. If you can't buy a replacement part, then you are not going to get this deck up and running no matter what else you do.


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Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18247
Registered: May-04
.

Start with this; make a list of ALL OF the replacement parts a 35 year old reel to reel will most likely need.

Figure all rubber parts.

Power supply caps.

Look for ic's and transistors which may no longer be available.

Look at the heads and determine if they have enough wear to indicate they might need replacement. If there is a groove worn into the head, it definitely needs to be replaced.

Make sure ALL of those parts are easily available before you even begin to troubleshoot the deck.

There are several parts which could have been specific to this series of decks. A few parts simply will no longer be in production.

If you have even one critical part to the restoration which is unavailable or outrageously expensive, then there's no point in going further.


.
 

New member
Username: Mgarnel

CascaisPortugal

Post Number: 4
Registered: Aug-16
Thanks. Happy 4th of July.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18248
Registered: May-04
.

You're welcome. I'm already working on Xmas 2017.
 

New member
Username: Mgarnel

CascaisPortugal

Post Number: 5
Registered: Aug-16
Final log: not beeing able to fully understand the circuit and not having variac (nor a time machine) or other more advanced ware, with the help of a 16� soldering station, I replaced all caps (including the huge one near the motor), transistors and diods (had help from a guy in the store to find compatible components for the ones out of production) switching from germanium to silicium, lubed all cams, vaseline on the rubber wheeels, isopropol on the heads and other spots and, for the last 2 months, I'm hearing music like its 80s again. And the final cost was just under 100bucks.

You're right: an MP3 player with an acceptable DAC probably delivers better quality but it was killing me to simply give up on that (master)piece of simple electronics (no ICs, just Ts, Cs, Rr and Is; no leds, VU needles; no LCDs, analog counter).

Regards,

MG
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