I have repaired two 92B's with this technique.? It appears that as the choppers age, their timing effects the meter's operation (both of mine
showed meter pined to the negative stop).? What I did was to swap the cathodes of CR207 and CR213, that is I connected CR207 cathode to
the original connection point of the CR213 cathode and vis versa, connected the cathode of CR213 to the original connection point of CR207.
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This changes the timing of when the synchronous detector measures the signals coming from the chopper through the amplifiers, and compensates
for the delays caused by an aging chopper.
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As mentioned, I've repaired two 92B's with this technique, both meeting all specifications after this modification.
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Hope this helps in your efforts to repair your meter.
