Hope this helps on head cleaning too?...
I found yesterday that ebay had some stocks of Chemtronic cleaners, so if you don't have an Amazon account, these are also available:
https://www.ebay.co.uk/itm/Chemtroni...0/283597680940
Soak a pad certainly with IPA Isopropyl Alcohol (99.9%) and very gently press to the side of the entire head block azimuth unit. Hold it there, then gently turn the upper drum part to where the tiny head slot is located (usually 2, but some can have 4) so that then contacts with the wet pad and slowly turn the drum back and forth about 3 times.
Once done remove the pad and you should see a blackish line if any dirt was removed.
Never then reuse the pad, even if you can't see anything on it. Get a fresh one and repeat for the other head(s).
Retain the plastic sticks though as then you can reuse them again, with a new bit of Chamois strip cut from a large cloth that's widely available from most suppliers
It's true also (certainly for the VCR's I get in) many have dirty tape paths so it will be best to clean up everything before running a tape.
Most faults incidentally are just: worn pinch-roller, reel idler, broken and/or bad belts.
Being mechanical, it's a joy to work with as you'll be able to easily see which parts need replacing!
Getting the bits sadly is now the only real problem.
Also lastly, once/if you do get the machine to play, if the picture displayed is bad and looks like the heads could be worn out... just try a fastforward playback (if the machine has that function) as I've found in the past what looks like a sad tale of a dud head, actually it CAN be just a stubborn bit of gunk (possibly from a mouldy old tape!) that gentle cleaning didn't shift but a highspeed rip-through playback actually can clear!
This 'trick' also works well on Umatic machines too, as experience has shown their heads can clog-up badly certainly if bad tapes are used, and often machines are scrapped as it was assumed the heads were gone, but again it's just dirt.