Hello
? One of my tekkie guys sent me these notes today, they concern the Valiant I & II Transmitter. He felt I should pass them along.
?? Issue: RF flashover on SW3B. ( rear wafer)
Details: The front and rear rotating contacts of SW 3B are fixed to the rotating ceramic "axle" of SW 3B with 6 small hollow rivets and separated by a very very small bit of ceramic.
?? The 3 rivets which fix the front rotating contact ring pass through the rotating ceramic "axle" of the switch and are terminated with swedged-over heads.?
?? The swedged-over heads of these 3 rivets are very very very close ( less than 1/64") from the rear riveted-in rotating contact ring.
?? We have found the ceramic of this very small space carbonizes over time from random RF arcing, ( in some cases, all three rivets) resulting in RF jumping between the rear and front rotating contact rings.
?? What WE did was to grind the heads off of all 6 rivets, remove rivets and the front and rear rotating ring assemblies, replace the ceramic "axle of SW3 B, shorten the rivets, re-install the front and rear rotating contact rings, secure the rivets in their? holes with thin CA adhesive. ( The wafer of SW 3B should have been a much larger and more robust RF capable switch)
?( SW3A&B is the same switch assembly used for the Ranger, Viking and Valiant.)
? This effectively increases the spacing between the front and rear rotating contact assemblies of switch 3B to a much safer 1/16~1/8".?
?? We also discovered some burned fixed contacts on SW3W&B. We replaced these as needed during rebuild.
Thank You for allowing me to post this
Ashley
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Thank You
Kiss-Electronics
Ms Ashley Hall
183 N 5th PL.
Cornelius, Oregon
97113
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W7DUZ
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