Two big issues on TSR-8

[damaye]

Hi,

I just got my "brand-new" TSR-8. It's working (play and record, except on one track), but has two big issues I cannot solve myself for now:

- the timer LED is always displaying "00:00:00" whatever I do...

- when I press forward or rewind, it works, but I can't stop: in forward mode, when I press the "stop" button, it switches to rewind mode. In rewind mode, nothing happens when I press stop (or play). In the end, I can only switch off to stop rewind or forward

I have opened the TSR-8 and started to clean the dust a little, but it hasn't helped for now.

Do you have any idea/suggestion about the issue? Does it sound like a mechanical problem or electronic? Most recent test, without a tape in, tend to "make me think" it could be an issue with one of the motor's brake (if any).

Thanks for any tip/idea...

 

[jpmorris]

First of all, the TSR-8 will behave really strangely if you try to run it without a tape on. As an experiment, I lifted the tension roller on the right so that the capstan was turning, and hit fast-forward (and later, rewind). This does cause the reels to spin in opposing directions (for tension I presume) and it will not stop until the tension roller is relaxed and the capstan shuts off. If you hit stop, it will attempt to rotate in the opposing direction as part of its process of slowing the tape down gently. This sounds rather like what you're describing, so if you're checking it without any tape loaded it may indeed be working correctly.

First things first. Is the capstan turning? This is the silvery post just to the right of the head block, the one above the rubber pinch-roller. The capstan will only turn when a tape is loaded, or if you push the right-hand tension arm upwards.

Secondly, on the left-hand side of the TSR-8 is a roller with a black, grooved rubber tread. This roller controls the counter, and I believe the microprocessor also uses it as a reference for tape motion. If this has stopped working, you could get some quite odd effects.
You might try rotating it by hand a couple of times, to see if it changes, but be aware that the counter will only increment when the capstan is turning.

 

[witzendoz]

Hi,

The TSR8 reels and counter will not act correctly without a tape mounted on the machine and threaded correctly. Don't panic! there is proberbly nothing wrong with the machine.

The tape counter is activated from the large rubber roller with the grooves.

Please read the manual to thread the tape correctly, it's common for 1st time users to thread the tape wrong.

Great machine, have fun

Alan.

 

[damaye]

tsr-8 issues follow-up...

Hi,

first of all, I'd like to thank you for your answers!

First of all, the TSR-8 will behave really strangely if you try to run it without a tape on. As an experiment, I lifted the tension roller on the right so that the capstan was turning, and hit fast-forward (and later, rewind). This does cause the reels to spin in opposing directions (for tension I presume) and it will not stop until the tension roller is relaxed and the capstan shuts off. If you hit stop, it will attempt to rotate in the opposing direction as part of its process of slowing the tape down gently. This sounds rather like what you're describing, so if you're checking it without any tape loaded it may indeed be working correctly.

First things first. Is the capstan turning? This is the silvery post just to the right of the head block, the one above the rubber pinch-roller. The capstan will only turn when a tape is loaded, or if you push the right-hand tension arm upwards.

Secondly, on the left-hand side of the TSR-8 is a roller with a black, grooved rubber tread. This roller controls the counter, and I believe the microprocessor also uses it as a reference for tape motion. If this has stopped working, you could get some quite odd effects.
You might try rotating it by hand a couple of times, to see if it changes, but be aware that the counter will only increment when the capstan is turning.

To answer your questions: yes, I've tested with the tape loaded
I have also tested without the tape, to understand better how it works (motors turning in opposite order for instance), but what I have described is with tape fully loaded. Ten years ago, I used to record a lot with a Fostex-R8 (1/4" tape) so I'm not totally a newbie in the field, but as it's the first time I'm using the TSR-8, I have to learn a lot. About the cabestan, I've done tests again, and yes, it is turning when I'm playing the tape. But still displaying 00:00:00 all the time.

Here is a picture of the cabestan, while playing:
(first pic attached)

Hi,

The TSR8 reels and counter will not act correctly without a tape mounted on the machine and threaded correctly. Don't panic! there is proberbly nothing wrong with the machine.

The tape counter is activated from the large rubber roller with the grooves.

Please read the manual to thread the tape correctly, it's common for 1st time users to thread the tape wrong.

Great machine, have fun

Alan.

I think it's loaded correctly, but here's the pic!
(second pic attached)

Greets

 

[jpmorris]

Right. That would suggest that the tach roller has failed somehow. This is the left one with the grooved rubber coating.

What is supposed to happen is that it rotates a coloured disk between a pair of photosensors. Probably two pairs actually, so it can sense the direction as well, but I haven't disassembled that far. As the disk rotates it will detect the change in brightness and use it to determine the tape speed. This might be mechanical, e.g. the disk has come off or is not rotating, or it could be that the photosensors have failed.

It might be something as simple as the PCB connector coming off in transit, but that's where you (or a service tech) probably want to start looking.

 

[Beck]

First make sure the left tach roller is spinning freely by hand. It could be frozen. If you can get it to spin, lift up the right tension arm and spin the tach roller. The counter should advance if it’s working.

If it spins but doesn’t advance the counter, you can check the tach roller by removing it and checking the plate on the back surface. To get to it you have to remove the front panel, which involves removing the pinch roller, both tension rollers, and the screws on the panel. Watch out for tiny black washers on the tension roller shafts and panel screws. You don’t have to remove the tach roller or the metal guide roller on the right to get the panel off.

Once you have the panel off, unscrew the cap to the tach roller but watch out for a spring and a black washer so that they don't fall off a roll away. After the cap is removed, pull the tach roller straight out to remove it. The back plate should have an alternating silver and black pattern (looks kinda like a tape reel). If it is really dirty the sensors won't be able to detect rotation. Clean it off by spraying some windex or generic glass cleaner on a paper towel and wipe it off. It's best not to spray the windex directly on the part because you don't want moisture mixing with oil where it makes contact with the shaft.

If the tach roller isn’t dirty, the sensors might be covered with oxide dust. They are right beneath where the tach roller sits. Use a Q-tip dipped in isopropyl alcohol to clean the dust off those.

When reassembling put a small drop off sewing machine or 3-in-one oil on the tach roller shaft.

If that doesn’t do the trick, you may have more complicated micro-controller issues in the transport circuit.

 

[damaye]

...

Thank you both for your great answers! I'll look at it asap.

 

[jpmorris]

Looking at the schematics, the sensor PCB is connected to the control PCB via connector P7 which is in the bottom middle of the control board.
The control PCB is the large suspended one accessed via the back of the machine. IIRC there is a way to make it swing out. It might be an idea to do that and check that all the connectors are in place. If you have a multimeter, try a continuity test as well - there are only 4 pins or so, and there might possibly be a dry solder joint.

Assuming the connection is OK, the next step is to see if the sensor PCB is actually working. There are a couple of ways you can do this. Firstly if you have an oscilloscope and you know how to use it, you should be able to see if there is a voltage going in and a signal coming back as you turn the counter roller. You'd probably have to tap that from the control PCB while the machine is on, but be careful and make sure the machine is connected to a mixer for grounding - you may find the chassis at half-mains potential (!) if you power it on with no audio connections. All three of mine do this so it seems to be a design thing.

Alternatively, you can find out if the light sources are working. These are probably infrared LEDs, which you can't normally see with the naked eye. However, if you have a camcorder with a preview screen (a cellphone with camera may work), you may well find that it can see them. Try this with a TV remote first - point it at the camera and press the buttons, to make sure that it can see them light up. If it does work with the remote (and not all cameras do), try running the machine with the front cover off and the tach roller removed, and see if the sensors light up.

IMHO it's unlikely that the main control logic itself has failed since it basically runs everything and I doubt the machine would have booted in the first place. It's far more likely that it's just not getting the tach signals for some reason.

 

[damaye]

The problem...(?)

Hi,

I have followed your instructions and removed the front panel and got access to the left tach roller.

You can watch the picture attached.

What I see is a bright surface, with two small (rests?) of old stick. Is it supposed to have a coloured surface or something?
"The back plate should have an alternating silver and black pattern"

If so, I guess the problem is here: it's been removed! Do you think I can do it myself from a model?

--Damaye

PS looking at the sensors through a CCD camera, I can clearly see two light points, which are the IR light sources (only when main power is on).

 

[jpmorris]

What I see is a bright surface, with two small (rests?) of old stick. Is it supposed to have a coloured surface or something?
"The back plate should have an alternating silver and black pattern"

If so, I guess the problem is here: it's been removed! Do you think I can do it myself from a model?

It might be worth trying, or you could see if you can get one from a TEAC parts dealer. I actually have a couple of spare ones I bought last year for my parts cache - I think they're stickers. I can scan one in as a pattern if you like.

To be honest, I don't know how critical it's going to be to get it accurate. All told, it probably shouldn't make too much difference, since the speed of recording and playback is ultimately governed by the capstan system.

 

[damaye]

follow-up

It might be worth trying, or you could see if you can get one from a TEAC parts dealer. I actually have a couple of spare ones I bought last year for my parts cache - I think they're stickers. I can scan one in as a pattern if you like.

To be honest, I don't know how critical it's going to be to get it accurate. All told, it probably shouldn't make too much difference, since the speed of recording and playback is ultimately governed by the capstan system.

It would really be worth a try trying to fix that from a scan, I'm all for that kind of challenge (I can even pay for the scan if you think it's time-consuming and worth it). I guess that the most important information catched by the sensor is "something linked to a frequency" (the faster the roll is turning, the higher the frequency of colour alternance is), so it can drive the timer display accordingly (I guess the "conversion" is linear). What I mean is that if the new sticker image has the correct number of white and black "pies", and a good contrast, it "should be" totally accurate. In the worse case, I don't see it as a big issue if the timer is not totally accurate. What I need is mostly locators actually

On the other hand, I'm going to look for the real parts, but I'm unsure about TEAC parts dealers here in Europe.

Greets

 

[damaye]

... the only information I need is...

Following this discussion, maybe I don't even need a scan! I just need to know how many alternate white and black pies there are on the original roller! (unless they have not the same angles)

Then I can draw that easily, even by hand...

Greets

 

[jpmorris]

On the other hand, I'm going to look for the real parts, but I'm unsure about TEAC parts dealers here in Europe.

I don't honestly know if they sell overseas, but I think this is the one you want:
http://www.chsinteractive.co.uk/electrical-components/misc/tsr8-plate-guide-teac.htm

I'll have to check that is the correct part number when I get home, as it's one of the ones with no picture. What you might want to try quickly as a stopgap measure is using black marker on some sticky labels. The black bits need to be matt I suspect, and it's probably best if you leave the rest silver.

It looks something like this:

 

[Beck]

Hi,

I have followed your instructions and removed the front panel and got access to the left tach roller.

You can watch the picture attached.

What I see is a bright surface, with two small (rests?) of old stick. Is it supposed to have a coloured surface or something?
"The back plate should have an alternating silver and black pattern"

If so, I guess the problem is here: it's been removed! Do you think I can do it myself from a model?

--Damaye

PS looking at the sensors through a CCD camera, I can clearly see two light points, which are the IR light sources (only when main power is on).

Yep, You’re missing the PG plate, which has the pattern I described earlier. It should have three alternating sections of silver with three alternating sections of black, making it look like a mini tape reel or a pie cut into equal sections. The silver color is very shiny chrome looking.

It is Tascam part # 5801190400 – Plate, PG

Parts Department
TEAC America
7733 Telegraph Road
Montebello, CA 90640
Phone: 323-727-4840
Fax: 323-727-7632
E-Mail: parts@teac.com

It's best to call for faster service.

The two little chips (U1 and U2) on the circuit board beneath where the roller sits are photo sensors. They detect the bright and dark sections of the plate and work with a resolver circuit to keep accurate count.

You’ll definitely need to replace that plate, since a microprocessor depends on the data to provide for some transport functions, as well as the counter display.

Someone would have had to take it out, because they don’t fall out. Hopefully you don’t have a parts machine there with other bits and pieces missing.

EDIT: I just saw JP's pic... yep, it's kinda like that.

 

[damaye]

I don't honestly know if they sell overseas, but I think this is the one you want:
http://www.chsinteractive.co.uk/electrical-components/misc/tsr8-plate-guide-teac.htm

I'll have to check that is the correct part number when I get home, as it's one of the ones with no picture. What you might want to try quickly as a stopgap measure is using black marker on some sticky labels. The black bits need to be matt I suspect, and it's probably best if you leave the rest silver.

It looks something like this:

Thank you for the URL and the attached image. I quickly put in place some black stickers (before you answred, so I only have 4 pars: 2 white and 2 black) on the plate and... it works! The counter shows some activity.

So I'm going to set up the new one with 6 parts, but I have a question about the image you have posted: I can see some thin lines that separate the black and silver parts. Is it totally accurate? (this would mean: one silver part-one thin white separation-one black part)

Thx

 

[damaye]

Yep, You’re missing the PG plate, which has the pattern I (...)
Someone would have had to take it out, because they don’t fall out. Hopefully you don’t have a parts machine there with other bits and pieces missing.

I hope so too! I wonder what the guy who removed it or forgot to put it in place had really in mind! (or maybe he was tired and didn't realized, but in this case, he certainly not tried to make the TSR-8 operate after!

Greets

 

[jpmorris]

The image was just a quick sketch from memory. In a couple of hours I'll do a scan for you and check if the CHS part number is right (annoyingly they don't list the TASCAM part numbers).

**EDIT**
CHS do ship overseas, but you may have to ask for the shipping. It's unlikely to be astronomical as the plate would go in a jiffy-bag or at a pinch even a normal envelope.

 

[Beck]

The PG plate is a bit larger in diameter than the roller. Perhaps someone tried to force the roller out without taking the front panel off. In that case maybe the PG Plate is laying around somewhere inside the machine broken in half... or if God is smiling, still intact.

 

[damaye]

It works!

I've done new stickers with 3 black (and I left the rest of the iron surface untouched). I consider this as a "quick hack" and I'll order the official parts, for sure. Anyway, it seems to work perfectly now!

It has fixed both the counter issue, and the forward/rewind->stop problems

Thank you very much for all your suggestions, you have really an excellent knowledge of how this machine works!

Greets

 

[jpmorris]

Here's the part, still in its bag. The link I gave earlier is indeed for this bit, by the way. Anyway, have fun with the machine!