Pete KE9OA wrote:
The meter comes after the AGC transistor. The AGC circuit consists of a
germanium detector diode with a low-pass filter that feeds a DC amplifier.
The amplified DC voltage controls the gain of the 3 I.F. stages and the RF
amplifier. It is almost impossible to get at the RF amplifier and the mixer.
These devices are embedded in the bandswitch assembly, along with two of the
AGC diodes. Now, if one of those diodes is cracked, that could also cause a
problem.

Can you get into the switch assembly well enough to use a DMM with
a diode test function? An open germanium diode is definitely a prime
suspect. If you find an open one, you can just solder a replacement one
in parallel, since a little extra shunt capacitance won't hurt in this
case and it will prevent having to do further disassembly.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."