B-67 MKII weird speed issues

[ethyrvalve]

Hi folks,

My B67 has started giving me sass. After being off for a week or so while I was on vacation it started turning the reels at a noticeably slower speed (for both 15 and 7.5ips). I'm quite sure it's not the pinch roller. And the tension seems ok. Some days it works fine though. Could it be a problem with the phase lock loop?
Thanks in advance for any insight.

 

[RRuskin]

Hi folks,

My B67 has started giving me sass. After being off for a week or so while I was on vacation it started turning the reels at a noticeably slower speed (for both 15 and 7.5ips). I'm quite sure it's not the pinch roller. And the tension seems ok. Some days it works fine though. Could it be a problem with the phase lock loop?
Thanks in advance for any insight.

I had a similar problem with my 16 track Fostex when one of the capstan motor drive transistors started to fail. Replace all of them (there are usually 2) if that turns out to be your problem. If one goes bad the others can't be far behind.

 

[jpmorris]

I had a similar problem with my 16 track Fostex when one of the capstan motor drive transistors started to fail. Replace all of them (there are usually 2) if that turns out to be your problem. If one goes bad the others can't be far behind.

More than two, I'd say. If it's the same design as the 807, there's going to be six, two for each phase on the motor.

**EDIT**
Disregard that, it looks like the B67 is a single-phase AC motor. Having said that, I can't actually find the drive transistors in the schematics.