Re: Moreton Cheyney
OK on the purpose of VR1 & VR2.
I've just added a note on the full circuit to the effect that VR3 is ganged with VR4.
VR5 is some sort of preset gain or AVC depth?
I suspect the anodes of both V12 and V13 originally went to the rear connector via 2700pF capacitors, one of which is now grounded.
I had assumed that the outputs were in push pull but maybe the external amplifier has the combining stage followed by a phase splitter. There are two EF39s and two KT66s on the amp chassis.
There may be an odd error or two in my circuit because of the difficulty in accessing and even seeing some parts. A 3.3K resistor is hidden away under the rear tagboard such that you can't even see to where it's connected.
Whoever made the modifications didn't possess a decent soldering iron as many wires fell off during the circuit tracing and wafer 3 of the bandwidth switch may have had its solder tags mis-identified. See Bw3/2 which shorts out the anode resistor. Can this be right?
I'd have expected a ground connection in the circuitry around the cathode of V10 but the resistance to ground is too high for one to be (now) present.
Allan G3PIY
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