I got one for all of you smart people out there!

[King Mudduck]

I have a cobra 29 that has sit on a shelf for the last 6 months. Before it worked great but now something fishy is going on with it. It turns on...hears fine....but when i key it up it shows no power what so ever on the meter even though i can hear my self from the talk back......but no one out in cb land can hear me :shock: I looked inside for anything like broken wires or burnt parts tried different mikes and checked it with another meter but i can not find anything.

I tapped on it...danced for it and even said a little prayer but i still can figure this one out. Maybe i need to call an exorcist :twisted:

 

[Switch Kit]

your talkback heres you huh , take ex.speaker plug into pA , if that works it isn't the audio chip , IM guessing you already checked the mic right ? Really sounds like your final went bye bye , really a guess on my part without having your radio in front of me but thats' what it sounds like to me . Easy fix dude if that's the case. Had you had any antenna problems in the past ? best way I know how to fry a final is shorted coax and or antenna will do it without one knowing in a quicker like manner.

 

[King Mudduck]

Smoked final was what i thought also but i was hopping it may be something else. No antenna problems or anything else so i guess maybe it was just that parts time to go. Oh well,easy fix.

 

[Carl]

either the driver or final.

 

[King Mudduck]

Replaced driver and final also found a blown cap at C61. Replaced the two caps inside the radio by the power plug and the protection diode. Still the same symptoms.....so it's off the the CB shop i go!

Thanks for the help every one.

 

[King Mudduck]

Fixed. I thought i would try another final just to make sure and sure enough it works. I guess that first final was bad even though it was new, oh well.

 

[thetnhillbilly]

It would have been nice to know that one was bad before you put it in, huh? Glad to hear you got it fixed with only moderate headaches and financial outlay.

Is there a test procedure one can do before installation to test finals or drivers? Preferably something that doesn't require specialized equipment, like measuring resistance between leads.

 

[DTB Radio]

I sometimes do quick and dirty checks for good/bad by using an alligator clip contraption that has a 100k resistor going from 12 volts to the base of the final, a red LED in series with a 1k resistor to the collector, and the emitter going to ground. if the LED lights up, then the final is probably ok. It may not be great, but it is definitely showing gain.