The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

hello,,i think ive got it narrowed down to the mike amp/tr swt i.c.,,ic-4 the 4558 mike amp i.c..the voltages arent right..the voltages are as follows..pin 1-4.50 pin2-1.50 pin3-4.50 pin4-0.00 pin5-1.50 pin6-3.20 pin7-7.30 pin8-8.17,,,,as you see pin 2 and pin 5 are way off...i wanted to check and see if anyone else had any ideas what might be pulling voltages down on these two pins before i change the i.c..wondering if p.a. amp could be shorted but by looking at the block diagram it looks like tr-32 audio antennuator and i.c.4 mike amp i.c..bypasses p.a..amp maybe not...reason im wondering about p.a..amp when i do the p.a. test,,as soon as i plug in external speaker to p.a..to do the check..all i get is a steady howl..........ideas appreciated

for future references,i got this radio fixed...the problem was c-129 bad...i replaced the cap in the c-129 location...and tx audio back to 100 %