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Cobra 21 LTD ST Malfunction

Posted: Tuesday 20th Feb 2007, 1:40
by WD5150
:evil: I have a Cobra LTD-ST that I purchased (a refurb) It powers up but does not transmit or receive, it set on a shelf in its box for a long time before I installed it, so it's out of warranty. it worked for a short period of time, maybe 2 weeks then quit. Anyone who has any ideas, it would be greatly appreciated.

Thanks, WD5150

Cobra 21 LTD ST no RX / TX

Posted: Tuesday 20th Feb 2007, 2:48
by Rick
Is the display and meter light on? and is the TX LED on when you key up? If not check transistors Q10 and Q11. Let us know how you get on.

Rick.

Cobra 21 LTD-ST

Posted: Wednesday 21st Feb 2007, 0:14
by WD5150
Hi Rick;
Thanks for the fast reply, Yes to all, It all lights up and the TX lights when keyed. For all intent & purpose, it should be working, at first I thought it might be the antenna so I swithed to a known good antenna, same thing. :?:

Thanks again, WR5150-Roy[/b]

Re: Cobra 21 LTD ST no RX / TX

Posted: Wednesday 21st Feb 2007, 1:31
by Rick
Do you see any movement of the signal meter in RX and TX? check it on a few difference channels

Do you have a multimeter (DVM) if so can you check the voltage at each side of diode D8 and D12 in RX and TX. Let us know how you get on.

Rick.