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Where to find a replacement T1 for cobra 29

longhaireddwb

W9WDX Amateur Radio Club Member
Oct 8, 2008
555
30
38
Colorado Springs, CO
That pretty much is it. I found that T1 on this Cobra 29 LTD Classic is bad and I need to buy a replacement. Part number EI-28. Anyone know where to buy one? I know its bad as I took one out of another working radio and swapped it out and it came to life. Audio once again. But I'd like to have both radios working. Ha.

BTW, The 25 I had been working on a month ago I gave up on. Its parts now.
 

Well for one audio output transformer failures behind a TA7222 are quite rare. Have you tested the windings out of circuit?
The 25 uses the same output transformer ...
 
The number on the transformer from the 25 are not the same. Now I guess its possible its the same one. But different numbers so I didn't try it.

As far as why the transformer went bad...Someone ran the radio with a bad antenna for a long period of time. Took out the Driver and the D8 diode along with the transformer. Caps tested good but the resister that is connected to the driver was burnt toasty!

Thanks for the reply.
 
The number on the transformer from the 25 are not the same. Now I guess its possible its the same one. But different numbers so I didn't try it.
.

I'm not positive but at first glance and my feeble memory the circuits are near identical. I found both schematics on CBTricks.

Sry for the insta edit . I have seen several diode failures and the audio output cap fail but you have to all but weld the final to do that . Upgrade the cap and of course the diode is an easy test. Not like I don't believe but test T-1 out of circuit to be sure :)
 

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Three good ways to toast the Cobra 29 audio transformer:

1) MOSFET final

2) 10 Amp fuse

3) Or better, both.

A junk radio will probably be the simplest route. It's a part that doesn't frequently go bad, so a 5 or ten buck yard sale radio is probably a safe bet for that part.

73
 
I have a parts 29 that you can have transformer if I can find it. I'll give a good look for it tomorrow

Edit: mine is stamped TF-129 ?
 
Last edited:
Thanks for the offer of the part but that is not the right number. Guessing I'll do some testing to see if there really is a difference between these transformers. They might have the same values in the end, just different numbers for the different radios. Who knows.
I should be able to find another used radio around somewhere. I bet a new transformer, if possible to find, would cost as much as 20 bucks. Thanks for all the help and reply's on this.
 
Great. Thanks for letting me know. I'll give it a try. When I get the chance. For now at least I know what the issues are and both will come to life soon.
i have 29 for parts if you need pm me i recently sold a user on here the audio chip. i just ask to pay shipping fees thats all if your intrested.
 
i have 29 for parts if you need pm me i recently sold a user on here the audio chip. i just ask to pay shipping fees thats all if your intrested.
Kaos sent me a working part. The radio I put it in has a gnarley final. Told Kaos that it was going to be my bench radio. Little to hot for that. Yes he only asked for shipping fees tip that man.
 

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