Cobra 142 no rx no audio

[coldfront]

Radio Make and Model: Cobra 142gtl
PCB Number: PC 385AG
PLL Number: MB8719
Test gear available: Vtvm, freq counter
Symptoms: No rx, or audio. No meter deflection.

What is working: Rx light, meter lamps and channel selector display.

What has been tried: Votages from power supply and regulators are close to spec.
10.24mhz at tp1

Did it suddenly happen ?: Ebay rip off.
Anything else that may be of help?: Would like to troubleshoot methodically not just shotgun replacement of suspect parts. I am no radio technician but would like to learn a solid troubleshooting method.
Thanks

[coldfront]

Found a shorted electrolytic 220mf c113 coming off of audio amp but still no rx. Tx was probably working all the time and I was shorting the wrong two mike pins as I have no mike for this.