Anyone with experience with the ALC circuit?


 

I have an IC7000  that has problems with the ALC circuit.
The ALC voltage is about 3 volts unless USB or LSB is selected and then it drops to 0 and no output.
The ALC is pegged and no power out.
I found a bad 4.7K (R1634) resistor in the UNSB circuit (Q1606), but this made no difference.
D 1606,7,8, all have about 7 volts on the OP amp side and 0 on the ALC side when the mode is SSB.
There is no indication of a short circuit for DC with the radio off.
It seems that something is pulling the line down.
Any guesses or suggestions?

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