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Old December 26th 04, 01:37 AM
John Steffes
 
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Default Hallicrafters S40-B

Recently acquired a Hallicrafters S40-B reciever that was DOA. We made a
few repairs and got it working (including some tube replacement and coil
damage repair). We were a little alarmed when some of the voltages on
the screens & plates were a lot higher than they should be. We then
checked the schematic with actual resistor values and they came close in
agreement with each other. Especially concerned about the higher
voltages on the R.F. AMP tube (6SG7). Any suggestions?

Also; has anyone looked into making a temporary mod to change the BFO
into a Q Multiplier? The idea would be to add a .005, 500WVDC capacitor
from the grid of V5 (6SC7) to the plate of V2 (6SA7), and inserting a
50K variable resistor between pin 6 and ground of V5 (6SG7). The 50K
variable resistor would act as a gain control and affect the "Q" or
bandwith.

John

KE0GG