Tascam 38 help

  • Thread starter Thread starter RossHammond
  • Start date Start date
R

RossHammond

New member
Hey Everybody,

I've read this site for a few years. It's very informative and I'm so glad it's online. This is my first post.

I need some help w/ my Tascam 38. I've been recording on it for a couple of years now. It's given me no trouble and it has been pretty reliable so far. However in the past few days it has started acting up by no longer stopping when it is being rewound.

If I rewind the tape and push the stop button, it will slow down and then immediately fast forward. Grabbing and slowing down the takeup reel worked for a bit, but now if one does that the reel stops but the belt (?) and the counter continue to run. The only way to stop it now is to power off...

I'm assuming this could mean a belt replacement, but has anyone experienced this before?

Thanks for reading,
-Ross
 
There's a switch which acts as a trigger to turn off the drive motors that's built into the right tape tensioner arm assembly. Is the tape tensioner arm stuck in the up position? Try moving it up and down a few times to see if it can be loosened up. Otherwise, I'm not sure what else to suspect. The belt in the 38 only drives the capstan, not the reel tables, which each have their own direct drive motors.

Good luck!

Cheers! :)
 
Another possibility is that the control IC is no longer doing what the manual says it should. I'd have to double-check the truth-table and see what its usual behaviour is.

I hope it's not that as these chips were custom-masked. Since TASCAM printed all the logic states for the machine in the manual, it would be possible to make some kind of replacement out of NAND gates or something (I could likely have done this at college) but it would be an 'interesting' task.
 
Try running through all the functions on the transport control buttons to isolate to only what you are experiencing with the RW and FF situation. Any other issues here?

Are you using an RC-71 or other remote or have access to one? Plug it in and bypass the tape machine control button to see if it does the same. If it does, then the tape transport IC as JP surmized is the likely culprit. If all is fine on running the remote then the transport buttons/contacts would be suspect IMHO.

I'm pretty sure your capstain belt is not the problem.

The digital counter continuing to run is curious. I think it is tied into optical photo sensors reading a sloted rotating disc mounted on the right reel motor...so the digital counter should correlate to the speed/direction of the reel motor.

The switch on the right tensioner GFM refers to is a main switch for the reel motors, so I dont believe the problem is there.

Get an operation/maint manual if you don't have one. Have you cleaned the transport path and opened up the front panel of the machine to clean internally as well?

Hopefully you can utilize the RC-71 to try some simple toubleshooting and report back.
 
There is some good news - I was wrong about the control chip being a TEAC special. The '32 uses the Mitsubishi M54410P, which is actually an off-the-shelf tape deck logic circuit used by Denon among others. While it may be a little hard to get, they are out there if you do need one.

Of course, I'm assuming that the '38 is using the same controller - but I'd be a bit surprised if it wasn't.
 
Thanks

Awesome...thanks guys. I'll try this and report back!
 
OK, so I just tried some of your suggestions and here goes:

I plugged in the remote, bypassing the control panel and played/fast forwarded/rewound/recorded etc. off of that and everything worked fine for a bit. The tape now rewinds, but sometimes the tension arm seems to stick a bit, preventing the tape from stopping.

I unplugged the remote and basically it's a fairly normal operation, except for the sticking, so it doesn't seem like it is the IC.

Also, when I play the tape now the counter will quickly jump ahead about 20 or 30 numbers before the tape starts playing. Weird...Could this also be due to a sticking tension arm?

I was able to finish a recording today, but it would be nice if I could get the thing back to its' normal health.

RH
 
Make sure...

Make sure the reel table is securely affixed to the reel motor shaft. Likewise, make sure the counter/rotation sensor is properly affixed to the reel motor shaft. It sounds like maybe some slippage or an encoder problem.:eek:;)
 
Last edited:
RossHammond said:
OK, so I just tried some of your suggestions and here goes:

I plugged in the remote, bypassing the control panel and played/fast forwarded/rewound/recorded etc. off of that and everything worked fine for a bit. The tape now rewinds, but sometimes the tension arm seems to stick a bit, preventing the tape from stopping.

I unplugged the remote and basically it's a fairly normal operation, except for the sticking, so it doesn't seem like it is the IC.

Also, when I play the tape now the counter will quickly jump ahead about 20 or 30 numbers before the tape starts playing. Weird...Could this also be due to a sticking tension arm?

I was able to finish a recording today, but it would be nice if I could get the thing back to its' normal health.

RH
Click to expand...

Do you have a different tape to try on the 38? There's a possibility that the tape in use may have the early stages of sticky shed and that can make a transport do very strange things. Is the tape path clean? Any unusual build up of oxide dirt showing on the heads and guides? Are you using the machine in an above average heat and humidity environment? Is the tape squeaking at all as it plays? These are signs of sticky shed and if so, the tape will need to be baked in a dehydrator to dry back the binder glue that holds the oxide to the tape's backing layer.

The best way to really get to the bottom of this is to try a process of elimination steps and putting a fresh, new real of tape on the machine is one of those steps to see if the behavior of the transport changes. Clean the entire tape path first and then try a different roll of tape. The other thing about doing a process of elimination steps is to do the simple things first before you start worrying about IC chips and lose mechanical parts inside the recorder.

Let us know.

Cheers! :)
 
Excellent observation and suggestion there Reel. Curious what the transport functions are doing with the deck in "Zero Return" mode and out of "Zero Return"..can you report back??
 
Last edited:
You must log in or register to reply here.
Back
Top