COBRA 25 NIGHTWATCH NO POWER

148 · Post by **148** » Wednesday 20th Feb 2008, 14:16

HAVE A COBRA 25 NIGHTWATCH THAT HAS NO POWER AT ALL GOOD FUSE,GOOD POWER SUPPLY JUST STARTED LEARNING ABOUT RADIOS SO ANY HELP WOULD BE VERY GREATFUL THANKS FOR ALL INFO

ramblingman · Post by **ramblingman** » Wednesday 20th Feb 2008, 14:21

if it has been hooked up backwards..you probably have a shorted reverse polarity diode..

148 · Post by **148** » Thursday 21st Feb 2008, 14:29

could not say it was given to me like this what is the location and what should the readings be thanks for all the help

hotrod · Post by **hotrod** » Friday 22nd Feb 2008, 11:25

not to get off topic here but was just curious i gotta cobra25
that keeps blowing fuses as soon as ya hook it up to a p/s
or car battery.is this the same problem?

148 · Post by **148** » Friday 22nd Feb 2008, 12:06

hotrod mine does not blow any fuses but I did have one like that and the little plastic insulator was missing behind the final and audio chip you might want to make sure all insulators are there

hotrod · Post by **hotrod** » Saturday 23rd Feb 2008, 13:53

thank-you

148 · Post by **148** » Sunday 24th Feb 2008, 15:23

wish I could get some more help with this radio it would be great if anyone has so advise thanks again

Rick · Post by **Rick** » Sunday 24th Feb 2008, 22:21

The radio that keeps blowing fuses, change D17, it may look ok, but it is most likely short.

The radio that will not power up, check the voltage between Pin 1 of the audio chip IC1 (TA7222AP) and ground with the radio switch on, the audio chip is bolted to the side the chassis.

148 · Post by **148** » Monday 25th Feb 2008, 6:48

thanks for the input Rick I am getting zero voltage it does not blow a fuse just no power at all ckeck voltage at back of radio where the plug goes in and I only get like 2 volts so I changed the plug and same thing and I get no voltage at the final.audio ic,the on and off switch the power supply and plug I am using works fine on my other radios with no problem someone else said it could be the power protection diode but not sure where it is located as I am new to repairing radios but I enjoy doing it and I would like to say thanks Rick for all your help with mine and the many others you have helped out here where would guys like me be with out guys like you so thanks again for all your help and everyone elses

Rick · Post by **Rick** » Monday 25th Feb 2008, 10:55

change D17, it may look ok, but it is most likely short. This diode is at the back of the radio neat to where the power wires are the diode is black and is a 1N4003.

148 · Post by **148** » Monday 25th Feb 2008, 11:47

as always Rick is right you are THE MAN thanks again Rick for all your help I owe you one your friend hear in Michigan saying thanks again

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COBRA 25 NIGHTWATCH NO POWER

COBRA 25 NIGHTWATCH NO POWER

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Cobra 25 Nightwatch Dead.