Any capacitor (especially an old one, even more so where it's in a
very hot environment all its life) can easily go bad.
What are the values of the capacitors?
73, Jim W7RY
On 3/12/2023 3:13 PM, Bill Leonard N0CU
wrote:
The receiver
seems to work fine when the AGC switch is set to S. However, in
the M position there is noticeable distortion on both noise and
signals. In the F position, the distortion becomes significant.
The distortion sounds like clipping, but none is seen on the
audio output with a scope. The S meter shows no difference with
the three settings. I am using the Sherwood audio amp and power
supply. I set up an HP sig gen to provide a pulsed RF signal.
What I see is the AGC pulse in response to that input signal
increases in voltage by x3 in the M position and by x7 in the F
position compared to the S position. The only changes to the AGC
circuit that I see when the delay is changed to the M & F
positions are the time constants (two RC networks). The
resistors in those networks check ok and to the limited extent
that I can check the two capacitors, they seem ok. What types of
capacitors are they and do they have a history of going bad? Any
suggestions would be appreciated.
--
Bill N0CU
--
Thanks and 73, Jim W7RY
