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Old 8th May 2011, 3:58 pm   #2
ronbryan
Octode
 
Join Date: Jan 2003
Location: Guildford, Surrey, UK.
Posts: 1,958
Default Re: Bush TV12 Poor Contrast

It seems like low gain in the combined sound and vision stages.

Was the contrast control decoupling electrolytic 25uF (C31 Bush manual) changed?

Have you checked the screen grid volts on the early EF50 stages, V11, V12, V13?

Are the receiver section valve base pins making good contact?

I doesn't seem likely to be an AGC fault, as AGC isn't implemented, at least on the circuit that I have.

Ron
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