Just picked up a 959, The TX dead key is strong on the meters and shows on correct freq, but the RX and TX audio is just a buzzing noise, almost like the motorboating noise a cobra 29 will get when the cap is gone home. RX, even with another radio keyed near it, RX is only about 7~8 on the meter and just a buzz, other radio does modulate properly...
After looking it over:
The clarifier is modded
The radio is channeled with JP5 and JP6 switches
Q35 is removed
IC9 (6130) pins 6 and 7 were lifted?!?! The problem is the same with the pins connected or removed though...
Q55 has been replaced with a 2SA1012
Q54 has been replaced with the 100 watt B817E
I dont see any other changes...... Thanks in advance for any ideas on where to start!
I've seen that problem on older boards and the cause was low output from the 10.240mhz reference oscillator.
My second guess would be try replacing the RCI8719 PLL. Take a look to make sure somebody didn't try using the MB8719 and if so replace it with the RCI-8719.
Just ran all the channels, on RX it receives, static sounds normal, but when someone keys up in range, the RX has the same Ocilation noise as when it TX's ... I'm about to try a new 8719 to see if it resolves the problem, I'll let you know!
GRTS, Great guess!!!! The 8719 must have been the fault. I removed it and put in a socket just in case I needed to swap another one back in. Put in a spare from a 949 and the problem disapeared! Thanks for the idea, it was right on! ( It was a 2001 chassis too, your comment about older models...)
