Did you perform the checks with the Fozgometer and the voltmeter AFTER performing all the replacements and adjustments that you described, as well as before doing them?
If not, consider the possibility that there may be two problems present, causing similar symptoms. So the replacements or adjustments might have fixed one cause of the imbalance, but not a separate problem further downstream that may be causing a similar symptom.
That would seem to be pretty unlikely, but given all the things you have tried, whatever the explanation turns out to be will probably be something unlikely.
Swapping channels at the Steelhead inputs would be the obvious way of either ruling out or ruling in that possibility.
Good luck!
-- Al
If not, consider the possibility that there may be two problems present, causing similar symptoms. So the replacements or adjustments might have fixed one cause of the imbalance, but not a separate problem further downstream that may be causing a similar symptom.
That would seem to be pretty unlikely, but given all the things you have tried, whatever the explanation turns out to be will probably be something unlikely.
Swapping channels at the Steelhead inputs would be the obvious way of either ruling out or ruling in that possibility.
Good luck!
-- Al