- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
The Cobra 29, like most CB radios, contains a reverse-polarity diode whose purpose it is to protect the radio against accidental reverse-polarity hookups. Normally all you will need to do is replace the fuse, then hook the radio up correctly.
If that doesn't get you going, then possibly the polarity-protection diode is now shorted and will have to be replaced (or removed - not recommended).
Beyond that, my experience is that the next component most like to get damaged is the Audio Output circuit, either an IC or a power transistor (larger than a regular transistor). At this point you're going to have to take it to a repair shop.
if this is a used radio its because some golden screwdriver got into it but if its a new one then its the radio.Check the reverse polarity diode in either case to see if its burnt. If so replace it and see if it happens again.
d23 a 1n4004 diode second component from pa speaker port inside radio has failed. It is most likely that neg/pos polarity has been switched shorting this diode. It is there to protect your radio from reverse polarity as so it is names the "protection diode." 2 solutions first not recommended.
1. Cut the diode this will stop the directed grounding that is continuing to blow your fuse. 2. Go get a pack of 1n4004 and rosin core silver solder from radio shack and replace it paying attention to the direction it is installed.
just a side note the solder trace often burns in this area so a jumper wire soldered in around this bad area solder side maybe needed.
The radio was probably wired backwards at some point. There is a reverse polarity diode inside that must be replaced to fix this. If you have continued replacing fuses and plugging it back in, there may be further damage such as finals or audio amplifier chip as well. you will need to take the radio to a qualified repairman for service. If it is simply the reverse polarity diode, your bill should not be more than an hour's labor charge.