05-19-2009, 09:57 PM
Is this the 'standard' Jackson Bros. 6:1 vernier drive that was used in so many things?
4511DAF for instance?
http://jlkolb.cts.com/site/vernier.htm
[Image: http://jlkolb.cts.com/site/fotos/vdjb1fw.jpg]
If so, then like the author of that site says you might have some luck with a thorough cleaning and tightening the tabs. I see new ones around for sale and they fetch about 13 US$. I've got a bunch of old ones here but I'd hate to guarantee any of them for very scrutinous tuning.
The tuning cap should be very 'free' turning. Not loose, mind you, but not enough to cause any drag on the drive. If thats ok and the vernier still slips then it may just be worn.
Next option if its not one of the Jackson drives. If its the shaft-in-a-shaft type as used in old radios they almost always respond to a good disassembly and cleaning. There's tricks to getting them apart. Maybe a photo of yours would help make a determination?
4511DAF for instance?
http://jlkolb.cts.com/site/vernier.htm
[Image: http://jlkolb.cts.com/site/fotos/vdjb1fw.jpg]
If so, then like the author of that site says you might have some luck with a thorough cleaning and tightening the tabs. I see new ones around for sale and they fetch about 13 US$. I've got a bunch of old ones here but I'd hate to guarantee any of them for very scrutinous tuning.
The tuning cap should be very 'free' turning. Not loose, mind you, but not enough to cause any drag on the drive. If thats ok and the vernier still slips then it may just be worn.
Next option if its not one of the Jackson drives. If its the shaft-in-a-shaft type as used in old radios they almost always respond to a good disassembly and cleaning. There's tricks to getting them apart. Maybe a photo of yours would help make a determination?
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