Cobra 29 problem/troubleshooting

[Stormrider]

Hello all, newbie here.

My father brought home a Cobra 29 NW LTD classic for me to fix today. He says it's "stuck" between channels. The LCD display reads channel 19, and the rotary control doesn't change it. Also, he said the lights are dim, and have been since he got the unit, but that isn't major issue and I think it's unrelated to the channel problem.

Nothing is obviously cooked inside the unit. I started testing a few components for shorts and found TR22 (the 2sc1957 mounted on the side panel) measures ~1.5k ohms from C to E, in both directions. I thought it was odd, but maybe that's normal for that part.

Any ideas?

 

[Robb]

Yeah, check one of the switches on the front panel that says 'CH19' and flip it the other direction.

 

[Slam Dunk]

Yeah, check one of the switches on the front panel that says 'CH19' and flip it the other direction.

Nailed it!

.

 

[loosecannon]

i fixed a 29ltd with a problem that sounds like this one many years ago, and it turned out to be a cold solder joint on the channel selector switch.

get some good rosin core solder and retouch all the solder joints on the switch.

personally, i would use de-soldering braid to remove all the old solder and then resolder them all.

but thats just me.

good luck to ya,
LC

PS- the two posters above me have a good point.
if that switch that says CH 19/ CH 9/ NOR is in the CH 19 position, the radio will act like you are describing.

if that switch doesnt seem to do anything, try spraying some contact cleaner in the back of it and switching it back and forth rapidly a bunch of times.
(DONT use WD40)

as for the dim lights, there is a knob on the front called DIMMER, it should be all the way clockwise for max brightness.

if that is not the problem, then maybe your dad was feeding the radio with low voltage, like less than 12 volts.

good luck with it.