Cobra 25 NW ST Noise

[Mudbug101]

I got a Cobra 25 NW ST with the TRB-1 echo board and talkback. The NB and ANL switches control the on off functions for both the echo and talkback. I am hearing the high pitch whine of the engine when I have the radio on. It does not matter if you have the volume low or the rf gain way up. One key thing I have found is that it stops when the CB PA switch is turn to the PA setting. I don't know if the person forgot to connect the NB wires back up when the switch was converted. I would prefer the NB ANL to stay on all the time any way. Does any one have any suggestions how to solve the problem?

I have tried a 20 amp noise blanker and that has helped. I does not do this to the other plain jane cobra 25 I have.

Thanks for the help!

 

[loosecannon]

maybe you can use the other cobra 25ltd you have to compare with this one, and see if the correct wires are jumpered together.
LC

 

[Mudbug101]

The Cobra 25 NW ST is a 99 model whereas the Cobra 25ltd classic is a 91 model. Will they have the same wiring?

 

[9C1Driver]

No. With Cobra cb radio's the older the better. ANYTHING that says Soundcrapper on it is one to stay away from. The only way to make one work right is have a quality cb shop go through the radio and swap out some of the cheap inferior parts, and keep the soundcrapper turned off.