So you have a slipping dial pointer/tuner drive on your vintage radio. It will be old age catching up with it for sure:) The shaft may have dried grease in its bushings seizing slightly, or more likely, the dial drive cord has lost its "grip". They do stretch over the years. I recall
as an apprentice
having to do every faulty dial cord that came into the workshop, until we got a new apprentice that is :)
Best bet, BEFORE YOU START doing anything, even if the cord is broken, make a hand drawn diagram of exactly
how the cord runs. You may be able to find one that matches up to your radio here
, Short of that(as well as), take closeup photos from several angles.
Once you are confident you have an understandable diagram of how it is strung, you can proceed to mess with it.
I have to be honest, completely replacing the cord is what I found to be the quickest/most reliable way to repair them, but then I had plenty of practice in the end. If you don't
have the correct type of dial cord string, then repairs can be a fiddly, but effective option to attempt
First you need to determine if the cord is failing/stretched, or if there is a stiff bearing point. This takes a bit of hands on approach to determine. put some additional tension into the cord by pressing down on it and see if the drive improves. If it does, then you may be able to apply more tension into the drive by shortening it a little. Do this by carefully unhooking one of the retaining springs that secure an end, without removing the chord from the spring, retie the another loop knot(as many as you need to before there is no more room to do so) onto the spring to use up some cord shortening it. Apply a dab of nail varnish to any knot once secure to be sure that it does not come undone. You can just cut the knot away and retie if you wish also, just fiddly with the limited amount of string you have to work with. It often does not take much to re-tension
it. Sometimes it may be as easy as fitting the spring to another tighter hook point on the large pulley(if you are lucky) This can be about the time when you are thankful you made a diagram of the way the cord is strung,as things can get messy.
If it appears that the tuning gang is seized, then a drop of penetrating oil to the bush will help it. Work it back and forwards a little to work the oil in. The large pulley attached to the tuning gang can be removed here also if you wish to work on the gang. use some tape to secure the string in place to the pulley and it can generally be removed from the gang and secured back onto the chassis somewhere
, whilst keeping tension on the string. Check also the free running of any brass pulleys along the drive. It is imperative
that you don't
get any oil onto the cord itself or the drive surfaces of the pulleys. ... or you will need to replace the whole thing. A syringe is the best applicator of oil for these jobs. Lubricate
sparingly and as a last resort only.
Worst case, you may need to completely restring the drive anyways. I did suggest that at the start.
Good luck with your dial drive repair. If you need new cord, it can be purchased
from a vintage radio restorer
online or just take it to a vintage repair shop in someones back shed in your neighborhood