"Can you look at my late father's cassette deck? It's not working, there's no reel drive and it's chewing up cassettes..."
Yeah... why not.
So this turns up...
It's a large deck, dating from the late 70's, it's a three head machine (one record/play, one erase and one play only), two motor machine, and built like a brick outhouse. A check of the heads show little signs of wear.
Disassembly of the machine is fairly straight forward. My immediate attention is drawn to the rewind and take-up mechanism, as this will have undoubtedly suffered the ravages of time. In usual fashion, there is a set of idlers and clutches arranged to provide drive, and these usually suffer with age-related issues, as they're made from rubber. They all appear in good condition, however.
Stripping the front panel off allows better access to the deck mechanism, and careful cleaning of the rubber tyres on the idlers proves no improvement at all. There's just no drive to the reels.
Further investigation proves one of the motors is no longer running. Giving the motor a sharp tap with a screwdriver handle and it temporarily struggles into life. It's short-lived. It's spinning freely enough, just not when it's powered up. I wonder if it has a stuck brush or similar?
I see if there's any chance of getting a new motor. Nope. None. It's very obsolete.
Removal of the deck from the machine is required to get the motor out. Not a particularly easy task, so I took plenty of pictures, which I promptly managed to delete from my new camera by accident! Agh!
So, with the motor in my hand, I can see that it's been spot welded together. No chance really of repair. With nothing to lose, I drop the motor into the ultra-sonic cleaning tank, and leave it fizzing away for an hour. Plenty of nasty looking black gunge floats to the surface of the tank.
After removing the motor from the tank, I blow some compressed air through it to dry it and leave it somewhere warm overnight to thoroughly dry out.
I'm a bit worried about having washed all the lubrication out of the motor, so I squirt a bit of silicone grease through the mounting holes, in an attempt to re-lubricate it.
Refitting the motor, and.....
.... it runs! I give the unit a long soak test, checking all modes, play, rewind, fast forward etc. It seems to be a reliable repair!
Here's a quick video of the unit running, and a demo of the bias calibration function.