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Cobra 29 NW LTD Classic no power. Please help
Posted: Thursday 12th Jun 2008, 2:29
by lynch1013
My husband tried to hook up his cobra 29 to a power switch of another cb maker and fried it.

After opening it up I see the black lead coming off the power supply is fried crack and broken. Please tell me what I should replace it with and where do I get it? Also could there be any other components I should test? I fix computers but don't know much about radios. I am a quick leaner though.
Numbers printed on board are
4205
A068C-8-0
KEPC-060-J
in that order
Thanks for any help!
Christine
Posted: Thursday 12th Jun 2008, 4:54
by Animal
Sounds like you (ahem - your man!) has a blown reverse-polarity diode (+ & - leads hooked up the wrong way round without a fuse or one larger than 3 amps) If this is the case then you may have aslo burnt up the copper foil on the board on the + side too.
If you've got an ohmmeter you can quickly confirm this.
PS Welcome to the forum

Re: Cobra 29 NW LTD Classic no power. Please help.
Posted: Thursday 12th Jun 2008, 10:28
by Rick
Check diode D23 it’s most likely gone south.
Just replace the writing, which has burn up, and the diode D23.
D23 is at the back of the radio where the power cables come in.
Let us know how you get on.
Cobra 29 NW LTD Classic no power. Please help
Posted: Tuesday 25th Nov 2008, 14:46
by gengine
I'm a newbie, with no knowledge, but I have a 25 wx st with the same problem, hance it was a free radio. Burnt black wire, and an obviously burnt diode, D17 on board kepc-262-b. Is there a specific diode i need to use? My schematic has 1n4003, but mouser.com has 59 different diodes when you search for 1n4003. From what it sounds like, will "just any old diode" work? (as long as it's 200v 1A?)
Cobra 29 NW LTD Classic no power. Please help
Posted: Wednesday 26th Nov 2008, 13:58
by gengine
I found a 1n4003 diode at radio shack to replace mine, and used a clipping of the speaker wire to replace the crispy power wire. Is there anything else that I need to look for before hooking back up to power?