Question about Cobra 148 GTL 120-Channels Base CB Radio

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Huge static busts

A while ago my Cobra 148 was borrowed and wrecked. From what hes told me he reversed the polarity "by accident" im just wondering if there is a dummy diode or other saftey features to stop perminent damage. Cheers. Dan

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Re: Huge static busts

Like Benimur said, most all newer units have a protection diode that is there for the purpose of protecting the radio when the power cord is pluged in backwards. It doesn't take much to fix them, only a $.02 diode. Most cb shops only charge between $10 to $15 to repair them.

Rollin CBs
Mt. Vernon, TX

Posted on Jan 23, 2008

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Re: Huge static busts


Most if not all CB radios have a reverse protection diode soldered immediately right after the power connector. Its purpose is to provide a practical short if the wires are connected wrongly to a power source. This would cause the fuse to blow. The diode normally goes bad after a reversed polarity connection and therefore would need to be replaced. This diode is not in series with the B+ line but connected parallel to the power.

In some instances, other components would also fail: Power capacitors, Audio IC, TX finals and/or the switching/regulator IC.

Hope that this be of some help/idea. Pls post back how things worked out or should you need additional information.

Good luck and kind regards.

Posted on Dec 17, 2007

Re: Huge static busts

No non at all. Think im gonna have to send it off to be honest. If the protection diode had blown i dont think i'd get any life from it at all. Thanks for all your help though. Great site!

Posted on Dec 23, 2007

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