148 gtl rx feedback
Posted: Tuesday 8th Jul 2014, 3:04
Radio Make and Model: Cobra 148GTL SN: 13011503
PCB Number: PC412
PLL Number: MB8719
Test gear available: RF Gen. Fluke 20MHz Dig Scope, 4 1/4 + 3 3/4 True RMS digimeter, RF probe, Freq Meter, Tektronics 10MH analog Scope, etc..
Symptoms:
Strong RX feedback when SSB selected (upper and Lower), S Meter goes full scale, even with Microphone removed.
Look like I have some IF amp to mic amp feed back.
What is working:
AM RX, SSB and AM TX.
What has been tried:
Did it suddenly happen ?: Yes
Anything else that may be of help?:
Some time ago, I had some ssb/am switch noise.
I saw R96 and R95 cutted...
PCB Number: PC412
PLL Number: MB8719
Test gear available: RF Gen. Fluke 20MHz Dig Scope, 4 1/4 + 3 3/4 True RMS digimeter, RF probe, Freq Meter, Tektronics 10MH analog Scope, etc..
Symptoms:
Strong RX feedback when SSB selected (upper and Lower), S Meter goes full scale, even with Microphone removed.
Look like I have some IF amp to mic amp feed back.
What is working:
AM RX, SSB and AM TX.
What has been tried:
Did it suddenly happen ?: Yes
Anything else that may be of help?:
Some time ago, I had some ssb/am switch noise.
I saw R96 and R95 cutted...