[old_tv_nut]

Update:

I ordered a can of Blue Shower, then made sure my will was in order after reading all the warnings on the can!

The Blue Shower removed a lot of visible gunk, but didn't free up the mechanism (as expected apparently has no lubricating qualities). Application of oil with the mechanism held in a couple of different positions to get it to run into various places did the trick.

Had to restring the fine tuning pulleys (original problem with loss of fine tuning action). Unfortunately, I managed to pull the string loop on one end out of the teensy brass ferrule that crimps the loop. I managed to reopen the ferrule with a needle and jeweler's screwdriver, but couldn't get it to crimp down again well enough. So, I made a loop with a double knot, and restrung everything. This turned out to be easier than I expected (never did one before), but of course the string is now slightly shorter, so it's wrapped onto the tuner-end pulley (where the end loops are) a bit peculiarly - but it works. It's got a tiny bit of slack, but not enough to run off the pulleys, and I'm hoping it won't stretch in the future.

One thing I will have to go back on - in partially disassembling the gearing, I slipped the VHF channel selector a cog and it now indicates one channel off - 3 shows as 4, UHF shows as 2, etc.