It sounds like a tube going south. To find out for sure have him pull one tube
at a time and operating on 1 tube (will work) untill he finds the supspect
tube.
Then once found hold the tube up side down and rap it with a wooden mallet( on
the top of the tube). The reason is that some of the Gold plating from the grid
is loose and shorting the filament. 8875's are getting impossable to find now
days some do show up on ebay but at $300+ each used. I have a MLA2500 that I
have converted to Russian GI-7B tubes ($20-35 each) and get 1300W out. It costs
about $250 to do the conversion but that includs the cost of the tubes & a
spare
set also.
Hope this helps
Roland AH6RR
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|