Re: Ferrograph 4A: Restoration advice needed
Lawrence's comment led me to go through the voltages in the manual and discover some components that previously tested good, but changed in use. One cathode was grounded, for example.
However, some measurements are far enough out that I think they're beyond tolerance, so it would be interesting to see what others think.
V1a: 46V - 15% high.
V2a: 72V - 31% high.
V3a: 85V - 42% high.
V4a: 248V - 3% high
R28/R29: 238V - 11% high.
R27/R28: 206V - 23% high.
R7/R27: 154V - 28% high.
Attached is the relevant part of the circuit (full diagram download link earlier in the thread) and the pages from the manual for reference.
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