[R-390] Re: r390, not the a, audio problem, possible agc problem

[ToddRoberts2001@aol.com]

If the audio comes through in the receiver only when the limiter switch is 
turned on, it is very likely a problem in the Limiter circuit. The limiter 
circuit in the R-390 non-A is in the IF chassis, not the audio chassis. You 
have indicated no difference when subbing another audio chassis, so this 
points to the IF deck. I would check the components around V507 and V510. 
There are some high-value resistors in this circuit that can open up or 
radically change value. 73 Todd Roberts WD4NGG.