HELP with Tascam 38

G

Good Friend

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My Tascam 38 reel was fine until yesterday when it started acting up. All of a sudden its making a high pitched "whirring" sound (coming from inside the deck, not in the recordings). Also, sometimes the recorder doesnt stop at 0000 and it continues to rewind. When it does this, the remote doesnt function and neither do the buttons on the front of the deck. I have to turn it off just to stop it.

All of these things went wrong at the same time and i never had these trouble before. The recorder still plays and records just as it always has, there is nothing wrong with playback or recording. Rewind and fast forward seem fine its just the stopping at zero that keeps messing up. Sometimes worse than others. All belts are new.

Can anyone tell me what might be wrong and what i might have to do to fix this? What kind of service fees does Tascam charge?

It just stinks because i am finally getting recordings that i LIKE the sound of and now its breaking.

Thanks for your time.
 
As far as the whirring sound Im not sure about that.
But I have a tascam 34 that does the same thing on rewind and fast forward sometimes.
I can sometimes hit the opposite function and it will slow down and then start to go the other direction and I am able to hit stop then. Most of the time this works but sometimes not.
Anyway I dont remember where I read about this but I think it was tascam that mentioned this can happen when the humidity gets to low in your home can cause this. If you can bring it up things may change on your machine.
I know it sounds goofy but its worth a shot before sending the unit off to someone.
 
The 30 series came out while I was working at TEAC, and I only worked on a couple of them so I might only be able to give hints. A few of the machines, most notably the X7R and X10R as I remember, had microcontrollers controlling the functions. A microcontroller is a a microprocessor, its program and data memory, and I/O all in a single integrated circuit. I've developed and brought many products to market since then that used microcontrollers, but I didn't know much about them at the time, and all we could really do anyway was determine if a part was bad, and replace it. (There were plenty of other machines that were logic-controlled without having a microprocessor. Those did not have this problem.)

Some of these machines had a problem in FF and REW where they would go out of control, and the only way to get control back was to turn them off and back on. I think what was happening was that if the fast winding speed was set too fast, the wheel with the photointerrupter used for the tape counter would produce interrupts faster than the processor could handle them. Even if you stopped the wheel by hand, the stack had overflowed, so the processor would crash. (More modern microcontrollers would use a watchdog timer to recover without outside help.) It's a problem than was not really solved while I was working there. If that's really what was happening, the solution would be to set the FF and REW speed a little slower-- although I can't remember if or how that could be adjusted, especially on the 30 series which I hardly worked on. Look in the service manual to see if there's an adjustment for that.

As for the brakes, assuming they're controlled by the microprocessor too, the processor will have to be running in an orderly fashion (not crashed) for the brakes to do their job. The humidity someone commented about could affect static discharges which conceivably could crash the processor, but a good equipment design should keep the static from causing that kind of problems.
 
With due respect, the schematics I have for the '32 show it is not microprocessor controlled. The control system (in mine) is a single IC which is an ASIC containing a series of logic gates. The manual actually gives the truth table so you can verify it's working correctly (and from that data I could probably design an equivalent circuit from NAND gates if I felt so inclined). Earlier models actually did use a bank of NAND gates, or so I've heard.

Anyway, a lot of the manual is common with the 38 although the control board itself may be slightly different. The TSR-8 and BR-20 are definitely uP controlled, but I'd be amazed if the 38 was too.
 
Humidity

I live in Arizona and it was raining the night i started getting the problems. It wasnt necessarily humid or unhumid, i just thought id mention it.
 
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