Tascam 38, sync/repro issues?

[gwargantua]

My Tascam 38 is exhibiting the following behavior: I recorded a tone to all of the first 4 tracks in "sync" mode. I played the tracks back in "sync" mode and channels 1 and 3 fade in and out from time to time. When I switch to "repro" mode, all 4 channels have steady signal. I repeated the test on tracks 5-8. Track 5 had NO output in "repro" mode but had signal when switching back to "sync". Track 8 acted like 1 and 3, fading in and out in "sync" mode. I swapped channel cards 5 and 6 and that problem appears to have swapped with the card. I have tried repeatedly cycling between repro/sync to exercise the relays and it sometimes seems to have an effect, but it is not permenant. I have thoroughly cleaned the heads and demagnetized them, along with all the transport components. The belt and capstan pinch roller have just been replaced.

Any ideas or similar experiences? Is this a common problem? Any comments, solutions, or suggestions welcomed. Thanks for reading.

[gwargantua]

I managed to find a thread that recomended leaving the unit on over night to help free some potentially sticky relays. I did so and the waivering dissappeared on all the affected tracks. However, channel 5 still has no signal on the repro output. I'm plan to pull the card and look at the relays next.

So nobody has had this happen before?

[Bill Furnett]

I haven't on my 38... yet.

I'm in no way shape or form an expert on the 38, or on anything for that matter, but hopefully one of them will come along that can offer some insight.


Interesting soulution for the relays, thanks for sharing it.

[MCI2424]

Originally Posted by gwargantua

I managed to find a thread that recomended leaving the unit on over night to help free some potentially sticky relays. I did so and the waivering dissappeared on all the affected tracks. However, channel 5 still has no signal on the repro output. I'm plan to pull the card and look at the relays next.

So nobody has had this happen before?

The relays have to be pulled and cleaned. One of the TASCAM crappy designs.

They SHOULD be in sockets so getting them out and cleaning SHOULD be a breeze. But, I don't have a 38 and don't know if TASCAM got way cheap and soldered them into the boards.

In any event, they should at least have plastic covers that pop off so you can clean the relay contacts. Use contact cleaner and keep it away from the circuit board.

Good Luck.

[Beck]

Originally Posted by gwargantua

I managed to find a thread that recomended leaving the unit on over night to help free some potentially sticky relays. I did so and the waivering dissappeared on all the affected tracks. However, channel 5 still has no signal on the repro output. I'm plan to pull the card and look at the relays next.

So nobody has had this happen before?

It is very common. It gets worse when a machine goes unused for a long time. The problem exists across many brands – the Otari MX5050 is another notorious for relay issues. The list of machines that don’t develop relay problems would be shorter.

Like other electronic components, relays have a max life before failure. The sealed type last the longest. However, the unsealed type can be accessed and cleaned.

Socketed relays can be good or bad. If you need to replace relays it’s nice not to have to desolder, but the contacts where the relay meets the socket can become oxidized even if the relay itself is fine. Thus a sealed and soldered relay can outlive other configurations.

Caig Deoxit is a good chemical treatment for serviceable relays.

~Tim

[gwargantua]

Thanks for all the replys. I haven't been able to check this thread for a while. They started blocking this site where I work, along with ALL "music" sites. How nice...

I'm going to have a look at the relays this weekend. The day after I got the waivering to go a away, by leaving it on all night, I tested it again. Well the waivering was back, so the effect was not permenent. I even left it on for a couple hours, with no change. Could that be relays too? The way it kind of fades in and out, and doesn't cut in and out abruptly, makes me think something "else"? Not sure what "else" might be though? Thanks again.