uniden pc-122

[tomthumb]

this radio recieves good all lights and meter works when u key the radio the transmit light comes on but it has no dead key and no modulation andf on my meter and freq. counter it showes nothing where do i start?

 

[Radioman1]

PC-122

Go to CB Tricks, look up your radio schematic

Here:

Uniden PC122

I would first check the voltages for the regulator, then Driver and final transistor

and let us know.....Mac

 

[JustinDePolis]

A few things to check... does it transmit on SSB at all?

If it does not, replace bias diode on 2SC2166, and also as previously suggested check voltages on base of the driver and final. If voltages are correct use scope probe to check for RF on the base of the driver, and final. If RF is present on the base of the driver, but not final, replace driver. If RF not present on base of driver, replace predriver, or check oscillator sections, and possible mixer stages.

Without test equipment, replace regulator, bias diodes on driver and final, driver and final transistors, and hope for the best. Set carrier to 3.5 watts AM, set ALC all the way up, then back off a tad, set AMC for 100% modulation. If AMC or ALC has been defeated, repair.

Set bias for 36MA driver, and 50 MA for final. plenty of idle current without sacrificing linearity.