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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
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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
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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
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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.


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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
 

New member
Username: Rotoman

Post Number: 1
Registered: Nov-18
I have a Sony TC-645 reel to reel that I am looking to sell. The problem I'm having is when rewinding the tape the stop feature does not stop the right reel and the tape gets tangled. The fast forward feature works fine. Any ideas?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18586
Registered: May-04
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Patient: "Doc, it hurts when I do this."

Doc: "Don't do that."






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New member
Username: Cpfirezine

Post Number: 1
Registered: Jan-19
I've got a Dokorder 8140 Four Track reel to reel. I have to keep pressure on the reel as it unspools onto the take up reel in playback to keep the tape squarely on the playback heads. After approximately half the tape spools off onto takeup, the problem goes away and the 2nd half of the tape tracks fine. Any ideas?
 

Gold Member
Username: Magfan

USA

Post Number: 3522
Registered: Oct-07
Reel-To-Reel is a very complex machine.
Even IF the electronics is perfect you still must deal with a fairly complex MACHINE.
Sometimes special tools are needed. Spring tension gauges. Special lubricants (spec'd by manufacturer) and
than the selection of mechanical parts which are frequently made of UnObTanium. You can probably get or fabricate from existing
parts, stuff like pressure pads and certain non-critical springs, but try for a capstan IF yours is rusty, bent or frozen in its bearings.

My Tandberg had ONE motor. But while it was playing, the take-up reel was wanting to go fast. This is normal for all tape machines and provides
tape tension. BUT, the FEED Reel had 'backspin' applied to it so the tape path over the heads had NO pressure pads, just the pinch roller at the capstan.
That was a very complex machine with dozens of linkages, lubrication points, o-rings used as 'belts' and even a CrossField head tossed in for good
measure.

As for CPfirezine, above? You've got a clutch from the motor to the feed reel. This allows the motor to spin freely while power is supplied to reel......
Does it rewind properly? You might need to adjust clutch tension to provide 'friction' so it unspools less freely.
This clutch is shot or needs repair. It has insufficient tension. Is the Dokorder a
3-motor design? If so, it's even worse. If a single motor, it sounds like a mechanical adjustment to the feed reel.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18631
Registered: May-04
.

IMO a reference to a Tandberg tape machine to a question about a Dokoder is like comparing a Ferrari to a Chevette. Similarly, how one was built has nothing to do with how the other was built. It also has nothing to do with the relative value of the Dokoder/Chevette.

A point to be taken from the discussion though is how much value you would ascribe to a vintage piece of electronics. If there are sentimental reasons for owing the Dokoder, there is no value we can give to repairing it. You spend what you want to spend if you wish to have a sentimental keepsake. Otherwise, I'd have to say putting much money into the Dokoder is similar to putting money into a Chevette with 180k miles on it.

Parts wear out and, particularly if the machine has been in storage, parts die. I'm unaware of any club that is dedicated to saving old Dokoders so you're going to have to find vintage parts for certain repairs or jerryrig parts intended for other uses to your repair. You've given no indication you can complete the repair if you can't diagnose the problem. Therefore, I assume most repairs will require a technician willing to take on a Dokoder.
Before we diagnose something over a forum from a distance, I'd suggest you find a tech in your area willing to do the work. Otherwise, what we guess at will mean nothing. We aren't spiritualists who can devine problems from a distance. You need hands on assessment and an estimate of costs.

It would be the very unusual tech who has specs for the Dokoder and an even more unusual tech who would care to take on the repair IMO. Most techs, if they are any good at all, have been saddled with a vintage repair where other parts are simply waiting to fail. They've learned their lessons from such repairs and don't tend to repeat their mistakes.

My guess, and it's only a guess is the belts have dried out and stretched out. But, even if that's correct, that's only the first issue with a 50 year old reel to reel. I would want to look at the entire machine before I even invested a dollar in the Dokoder. Even more parts might need replacement and adjustment.

My advice would be to not spend anything on the Dokoder. Find a vintage Tandberg with Dolby noise reduction if you want to use a reel to reel. Don't pump cash into a dry hole. Have something worth having when you're finished.

If you prefer to ignore that advice, find a tech who will work on this machine before you go any further.


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New member
Username: Cpfirezine

Post Number: 2
Registered: Jan-19
1) I want to play old tapes that I recorded in order to digitize them. Some are true four track recordings, so playing them on a 1/2 or 1/4 track machine won't help.

2) If I know what the problem is, I can do the work myself. My intention was to ask if anyone had an idea or had the same experience. I have the original manual and the schematic is in there, though I doubt that it's an electrical problem

3) I know it would be foolish to drop a lot of money into this machine. That's not going to happen.

Thanks for your replies. If anyone can give me good advise on the machine, I'd appreciate it.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18632
Registered: May-04
.

IMO we have given you good advice. Even if it comes down to replacing a belt, this is still a vintage component - possibly pulled from decade's long storage - with other parts that are likely to break in the near future.

Generally, if you can't do the diagnosis, you can't really do the repair yourself either. You can guess, but that gets expensive, particularly on a deck that isn't known for parts availability.
That's why techs existed with a shop full of tools and repair manuals and they went to school to learn how to do repairs.

Can you read a schematic and follow the signal path and the power supply path from input to output? If you can't, having a schematic doesn't help you at all. You need a tech who is willing to work on the machine and bring it up to OEM specs.

Vintage tape decks typically require a complete renovation to remove the old grease - which has probably thickened and may be the source of your problem - and replace it with fresh lubricant.

How are the heads? A worn playback head does you no good. Most Dokoders had permalloy heads which were notorious for wear. If it is a model with ferrite heads, the performance is not as good. Most reel to reels require adjustments to the tracking of the tape oath on a regular schedule. Do you have the information and tools and equipment to do that?

You might look into services that digitize tapes. In the long run, it will probably be less expensive and better quality. Even if you have a "reel to reel" deck, if the EQ set in the recording is not the same EQ as the playback machine, the tapes might not sound very good.

If the deck doesn't have Dolby NR, it is now considered one of the lowest sources as far as sound quality is concerned. About the same as AM radio.

So, what type of system are you going to play "true four track tapes" through if you get this machine up and running?


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New member
Username: Cpfirezine

Post Number: 3
Registered: Jan-19
OK, again - half way through playback of the existing reels in my collection, the problem goes away. This tells me it's not a worn head. Some of what I'm able to playback sounds pretty good. I'm aware of the issues old tapes have with regards to sound quality. This is true with analog tape no matter the format. I'll decide what I'm capable of fixing, thanks. I can read a schematic. I'm an electrician. As you probably know, most music is recorded on multi-track systems. It doesn't mean you need four channels for playback. I do all my current recordings an multi-track digital software and mix them to stereo. I have figured out that because the deck will play tapes fine from about the mid-point of the reels, that I can feed all four channels into a digital 16 track digital deck I have, record each separately until the tape runs out, flip the tape, fast forward, and repeat the process. Then I edit them back together, digitally reversing the audio tracks that played backwards and making sure the left/right aspect is correct if they're stereo or otherwise. A time consuming process. Then again, all analog to digital is a one to one transfer. My only time saver is that I can play back tapes recorded 3 3/4ips at 7 1/2", digitally stretch them 200%, which brings them back to proper time and pitch. I wouldn't use this to record ANYTHING at this point, strictly playback of about 100 tapes I have stored from years ago.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18633
Registered: May-04
.

Then I'd say you have this mostly figured out. You've asked for our guesses at the problem and we've given guesses. I never suggested heads were contributing to your specific problem. I mentioned the condition of the heads because most vintage decks would receive a suggestion to have the heads replaced in a refurbishment procedure. If the heads are worn on a vintage deck, the problems of using the deck for anything other than a wall ornament begin to mount rapidly. If you're satisfied tapes can play back with adequate fidelity, you are the final judge of whatever quality you find acceptable.

I'm sure you know the possible problems which might exist in your 100 tapes if they've been in storage for years.

There are no others who will give you other guesses who contribute to this forum at this time. As I suspect you know, troubleshooting is seldom accurate when done at a distance as a good bit of trial and error is needed to assess mechanical parts. So, even if someone else showed up, they would very likely still be guessing. Actually, this was never a forum geared to repairs so the chances of someone else guessing, right or wrong, are rather slim.

I would try new belts and possibly a pinch roller as rubber parts dry out rapidly if the deck has not been in use constantly. New lubricants wouldn't be a bad idea IMO. Leo suggests other repairs.

That's the best we can do from a distance. I would still suggest you find a technician willing to do a refurbish on this deck. If not that, look into either renting a four track machine for the time needed to transfer tapes or hand the job over the a service. Either of the latter two will likely save you a lot of headaches along with time and effort wasted. On the other hand, if you presently have more time than money, ...

That's all we've got.

As I've said, my experience tells me that if you can't manage a diagnosis, you probably can't finish the repair. There are limits to my experiences. I've never sold Dokoder. Tandberg and Tascam, yes. Dokoder, no. And, to the best of my recollections, I've never even seen a Dokoder in any shop I've worked in so I've certainly never seen inside a four track Dokoder.


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New member
Username: Henrydevid321

Alaska, Arizona
United States

Post Number: 1
Registered: Jan-19
You can also check https://ienjoyshayari.in/holi-wishes/ to find more details about that matter.
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