Hello there,
I have been bringing my recently acquired "cherry" 1500 back into the world. Everything works well at this point after working the switches/controls and keeping it running on and off for a couple of week. It sounds great, all controls work well, FF, Rewind, play, pause, etc. work fine. The tape lifters work as they should, all controls work great (no drop-outs) and the tape path has virtually no wear and is clean as a whistle. Pinch rollers have good pressure and do not slip.
The one issue is capstan speed in "Normal" that is, pitch control disengaged is a bit slow and getting flutter or wow (not sure which is which) per the strobe and listening.
With the pitch control on/engaged, the speed is locked in and steady as she goes, and adjusts to the proper speed (about middle of the pot range) and no speed issue at all. I suppose I can use it this way but I have a bit of OCD!
I do not know if this is related (probably is) but the reel motors (both) have more torque and turn more rapidly when the pitch control is on/engaged then when off.
I have looked at the circuit topology and the big difference I can see is that there is a quartz clock IC chip in the circuit with the pitch control off.
I have both volumes of the service manuals, a digital multi-meter, a freq counter and dual-trace Tektronics. I was a radar tech many years ago and worked mainly on tube equipment, not much solid state. If the IC is shot I hope I am not dead in the water as I know there are few parts around for Technics R2Rs. I have not pulled the Techics apart yet.
Can anyone help or may have seen this problem before and can suggest a good place to start? It is probably beyond my skills, so 2nd question is, can I send the capstan control board to someone for a look-see?
Thank you, Bob Edwards