Otari MX5050 speed control

[cafewalter]

I'm working on an Otari MX5050 Mk III 1/2" 8-tr for a client. The speed is a few percent low, with the speed control adjustment turned off.

The service manual does not include a schematic for the capstan motor PCB. (Every other stinkin' PCB in the machine is there, but not that one.) It seems that there must be a trim adjustment for the reference speed, but I can't tell for sure.

Does anyone either know how to adjust this, or have the capstan motor PCB schematic? Thanks.

[cafewalter]

Does anyone either know how to adjust this, or have the capstan motor PCB schematic? Thanks.

Investigation reveals that the capstan PCB is accessible from the underside of the machine, after removing the bottom plate and unscrewing the main control board. It has trimmer adjustments on it marked for H, M, and L; H is 15ips and M is 7.5ips.

Evidently no one thought through the ergonomics of working on the underside of a tape deck while it is rolling tape.

Anyway, if someone does have the schematic for the capstan PCB I'd still appreciate it, just for future reference. Thanks.

-walter harley
http://www.cafewalter.com