I've been following this thread, as I also have a JVC TD-541. It had a speed problem, as well as a start-up problem. I replaced the capacitors, and the tape speed is correct now. Thank you for all the helpful information.
Now, I need to pick someone's brain. When powered up, most often, there us no problem. Sometimes, the flywheels/capstans will just twitch once, and no spin. If I give them a slight push start, and they spin fine.
The mechanism was pulled, cleaned, flywheel bearings lubed with a tiny amount of white lithium grease, belt changed, same results after. It seems to happen most after it has been warned up. Any ideas why it won't spin up by itself?