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

WOO HOO!!!

Found the problem...

Several solder joints around Q402 were busted loose.
After melting out all the waxy-gooey mess, I noticed the joints moving about. A quick re-flow fixed it all.

Thanks again for your help Scott. I couldn't' have done it without you!

Homer

Pin 23 shows nothing in both RX and TX

Pin 24 shows 5.57 volts

R415 shows 7.79 on one side and 4.57 on the other.

All the zeners appear to be working as they should.

I sniffed around the board with my frequency counter and the only life I can get is from the 10.24 reference crystal. I typically don't work on these rigs, so I'm at a loss. I'm a 148, 29 and 25 fan and my old SAMS photos! Not having pin-outs and voltages makes it tough too. The radio is completely ...

Thanks for the reply... I'll give the PLL and VCO a look. I got the schematic off this site: http://www.freeinfostuff.com/CBs.htm Cobra 18 schematic: http://www.freeinfostuff.com/CBs/18-Ultra.pdf I would upload the schematic here, but I didn't want to get you (or myself) into any trouble in case it'...

Radio Make and Model: Cobra 18 Ultra Weatherband CB PCB Number: 411-032-d and number underneath that one: # 4a1030-d PLL Number: LC7185 Test gear available: Freq counter w/probe ability, Digital swr/power meter, 10a bench power supply, digital VOM w/transistor check. I also have the schematic, but ...