Tascam 388 problem

[Dr.Tube]

My Tascam 388 which have low hours, suddenly developed a crackling noise in the headphones and monitors. The noise is only present when the capstan is turning and is accentuated when I increase the load on the capstan. The noise is independent of any fader or switch, and everything is functioning. Capstan motor problem? Motor drive circuit problem? Have anyone experienced this problem? Solution?
Any help appreciated Thanks.

 

[A Reel Person]

I'm gonna wing it, but...

maybe it's an internal grounding issue, or a power supply issue???

Yeah, even a drive transistor or worn motor brushes, I suppose.

It's a bit esoteric.

That's a tough problem that you don't hear much about on the boards.

Your best bet on this one might be Tascam Service in Montebello!

Good luck!

 

[Dr.Tube]

Suggestions from "A Reel Person" appreciated.
I have now had the capstan motor loose from the bracket, and the noise diappears in certain positions of the motor, pointing to a problem with worn brushes causing sparks giving transients in the drive circuit, which are transmitted to the phone amp board, where the capstan speed switches are located.

 

[A Reel Person]

You're the man!

Sounds like you're on the right track!

 

[Beck]

Check decoupling capacitors in the motor’s associated circuitry.