cobra 29 audio/mod transformer hot!!!!

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Posts: 3
Joined: Tuesday 1st Jan 2013, 6:01
First Name: Mike
Location: Fargo

cobra 29 audio/mod transformer hot!!!!

Post by Bowwowwow » Tuesday 1st Jan 2013, 6:08

Radio Make and Model: Cobra 29 classic
PCB Number:
PLL Number:
Test gear available:
Symptoms: Audio/ mod transformer red hot within sec (smoking) as soon a power is appied

What is working: mic switch is not stuck, drops to 0.

What has been tried: d8, d23, replaced. Audio chip?

Did it suddenly happen ?: turned up slugs, might of touched something
Anything else that may be of help?:

Posts: 2
Joined: Monday 21st May 2012, 5:53
First Name: Michael
Location: Palmdale Ca

Re: cobra 29 audio/mod transformer hot!!!!

Post by cbsupertech » Friday 4th Jan 2013, 21:26

Hey Dawg...
Find the short, don't flail around guessing and hoping you replace the right one..
Desolder the leads/ find out if the winding's shorted to the other winding...see if your load is shorted to the print!!! C'MON!!!
••••••• Std. TECH PRACTICES/ TROUBLSHOOTIN 101 •••••••
I personally suspect your mod transformer itself is shorted...either internally to the core or secondary winding...
IT HAPPENS!! :banghead:
...especially with the low quality-made in china transformers
If you're smart you'll get the print and use your head, not yPour wallet!

wayword son
Posts: 1
Joined: Sunday 31st Aug 2014, 11:32
First Name: christopher
Location: United States

Re: cobra 29 audio/mod transformer hot!!!!

Post by wayword son » Sunday 31st Aug 2014, 11:49

having the same problem,soldered a 47 ohm 1/2 watt resistor for talkback now no audio.
everything else seems fine P.A. works through the mic. cobra 29 ltd classic built in aug. 2013.
replaced the audio chip. I get transmit until that chip gets hot then nothing
thanks for any help

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