05-08-2012, 08:25 PM
(This post was last modified: 05-08-2012, 08:31 PM by Robert Darwent.)
(05-08-2012, 08:54 AM)Geaney Wrote: Last night I checked all the relevant resistors (R6 through R14) and I replaced R6, R7, and R13. R6 and R7 were way higher than spec but R13 measured 80K versus the stated 250K.
Hi John,
As you have already checked R6 through R14 and replaced those resistors out of tolerance, the only other thing connected across that part of the circuit is the field coil (marked EXC on the diagram) with a specified resistance of 3000 ohms.
This set is quite unusual in having the field coil connected in 'parallel' instead of series with the heater/dial bulbs supply. Because of this it will have an effect on the negative bias arrangement. Check its resistance, hopefully it will be fine and the problem located elsewhere.
Regards,
