20 Most Recent Cobra 148 GTL 120-Channels Base CB Radio Questions & Answers

The problem is in the audio output chip usually bolted to the inner chassis. Sometimes the chip developes a hairline crack, replacement recommended.

1 - shield, 2 - audio, 3 - rx, 4 - common, 5 - tx

It is very likely that the reverse polarity diode inside the radio is shorted, usually because the radio was connected up incorrectly.

Try Cobra tech support here: Support Cobra Electronics Corporation

Try here Support Cobra Electronics Corporation

Cobra technical support here: Support Cobra Electronics Corporation

Check this Fixya thread about the same problem

I would say a bad or cold solder joint on board somewhere. Bad quality control. Might flex radio chassis slightly while keying? A tooth pick and hours of probing around switching area on board and the pa section till problem found.

The radio needs to be tuned for the box. 3 watts sounds too high for a 2x8.

I would say it would be more like 1-1/5 to 2 watts. That may be why your not getting that much swing.

You should set the radio so the box dead keys around 300 to 400 watts.

so whats wrong with it?

final

Have you checked the 2sc2166 or the 2sc1969? Those are the RF Driver and the RF Final output transistors.

bad ground .

you cannot do it . take it to a tech .

change the reverse polarity diode.

bad ground inside radio or cold solder . Be careful of rf burns.

five pin /4 pin? (white D-104?) five pin= 1-audio,2-shield,3-RX,4-comm,5-TX 4 pin=1-shield-comm,2-audio,3-TX,4-RX

google it

I'll bet that the A.W.I. is out of adjustment. give it a little twitch of a turn and see if the red light goes out.

Center the antenna on the vehicle, then check the SWR on channel 1 and channel 40.
with the switch in CAL position, key radio and use the swr/cal knob to set the meter so the needle is just touching the end of the red area on the right-hand side of the meter.
Once calibrated, unkey and switch the switch to SWR and key up again. The lower the reading, the better. If the SWR is Higher on 40, the antenna needs to be shorter.. if its higher on 1, then the antenna needs to be longer.

if it dont transmit period on AM, then there's an internal glitch :)