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Cobra 29LTD Classic PLL/Display problem

Unit 75

"TRAINMAN"
Jul 29, 2014
527
1,027
153
Central Alabama
I had a 2005 Cobra 29LTD classic brought to me.... initially to have the channel display replaced. The original was missing a few of segments. Prior to doing any work I bench tested the radio into my dummy load and it seemed to transmit just fine and on frequency. I replaced the channel display with a stock one from a 29LTD. Once it was put all back together, I turned it on and flipped thru every channel to make sure the display read correctly and had no drop offs. Everything looked great. I then hooked my coax from my dummy load up to it and turned it back on to transmit into the dummy load. As soon as I screwed the collar from the PL259 on to the SO239 the display read ch28 when I was on ch20. The radio keys and puts out power but on ch40. I thought what the heck. I undid the coax thinking something was causing the radio the short...so as a test...I hooked a alligator test lead from the center of the SO239 to ground thinking it would do the same thing but it didn't. The display read correctly. I have never EVER seen a Cobra29 do this before and have no idea why its doing that. Does anybody have some insight into what may be causing this "possession" ?
 

just spitballing here, but you might try putting an ohmmeter from chassis ground to PC board ground, with and without your coax to the dummy load connected.

in both cases, you should have no DC connection between them.
LC
 
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