My friend,...
I don't want to come out of the box immediately questioning your details, but in normal circumstances (this may not be a normal case)...
The Left reel should spin CW in all modes,... a little less torque in Play and FF to provide back tension and a lot more torque in RW mode...
The Right reel should spin CCW in all modes,... a smaller amount of torque in Play and RW mode to provide (takeup and back) tension, (respectively), and a lot more torque in FF mode...
The fuses should be verified with a DVM (ohm meter) for continuity, and not just rely on how they look. I've seen fuses that looked okay and still tested bad.
When you lift the R. Tension roller, the capstan should spin CCW.
When you press Play, the pinch roller should actuate up to fully contact the capstan. If it does not do that, it could indicate either a mechanical or electrical failure in the solenoid section.
Further, you should at least pull the face plate off and verify the hub brakes are fully releasing,... and if not could also point to a solenoid problem. Be very careful when removing the rollers, as there are some very small washers there that could get lost.
In the course of thinking methodically about proper function, past ohming out the fuses, it might be a good idea to verify the supply voltages.
I would not start twirling dials on the Reel/Servo card (or any other card) until the basics have been absolutely verified.
(Note: I believe, from memory, that I found a misprint in the manual on the location/function of pots on the Reel/
Servo card, where the FF and RW tension adjustments were mislabelled. This threw me for a loop last time I worked on a 388 [years ago], and caused a lot of rework time needlessly til I figured it out. I thought I penciled in corrections into my service manual, but I can't find evidence of doing so. Anyone else reading this should take note and verify my findings, lest figuring I'm just losing my marbles at this point)....
Often times, a pulling and reseating of the cards in the motherboard can solve a lot of problems with connections that have tarnished and become incactive. This should be done very carefully, so as not to bend any pins on the mother board.
If all other things check out, per the above, PERHAPS and NOT ABSOLUTELY, it could be related to a component failure, such as a drive transistor, HOWEVER, twiddling the dials internally will not help or fix this hypothetical issue. It's a real in-deep, component level, point-soldering job-type thing to repair.
Start with the most basic things and work up, being cautious and VERY careful along the way.
Good luck!
