CM300 excessive mic gain

[arlojanis]

I have a CM300 that has very high mic gain. I reset mic gain in CPS to 1.5 and mic picks up a whisper 3 feet away. When I set mic gain to a high setting there is a lot of back ground hiss and more mic gain. PL deviation is normal. A new mic did not help. What else can I try?

[35echo]

Arlojanis,

I would check the ASFIC voltages and signal levels. That IC has all of the gain and attenuation stages in it.
It is programmed by the micro according to customer settings and tuner values. I would also check U507.
I dont think it is the problem but you could have something seriously strange going on.

Regards,
Allen

[com501]

If you have the capability, you might want to refresh the firmware also.

[arlojanis]

Firmware upgrade did not help.