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Old 1st Mar 2021, 2:34 pm   #210
Helder Crespo
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Join Date: Sep 2019
Location: Crystal Palace, London, UK
Posts: 211
Default Re: My first telly TV22

Originally Posted by Travellingwave View Post
Here is link to video. Will try to get rewind done some time next week work permitting.
Based on the post-mortem, where do you reckon the short took place? From your video it seems to have been roughly in the middle of the central portion of the coils. Quick question: I known it can be very hard to determine, but were you able to check if the paper was / had been impregnated with white spirit in that area? As for the rusty ends of the laminations, my varnished lopt was in a very similar condition to yours. I think that if the problem is only at the top/bottom, this should not make a huge difference in performance (the magnetic circuit is open/lossy anyway), apart from potential vibrations that can be minimised by tightening and restraining the ends. The rust layer is actually an insulator, provided it is dry (or immersed in white spirit) and then varnished.
I never fully disassembled my lopt. Prior to varnishing, I simply squeezed the laminations together and machined a small restraining piece to keep them together (see photo below).
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