Key mic and backfeeds speakers/ turns stereo off???

Having a backfeed issue.

I have done a search and found usually a radio poorly boosted will cause that or possibly coax in bad shape.

Just wanting some suggestions but i think tryin coax first will be the plan.

Uniden 78LTW, have owned since new. It's prob 4 years old now and was boosted to about 8 watts when bought.
Previously installed in a pickup truck under the dash with K40 antenna. Never an issue.

New gig ment i had to put it into the truck, 2000 379 pete. Running a single antenna on the passenger side mirror. Wilson antenna, forget model.

When I key the mic the radio goes nuts and even kills power on the deck. Also notice the antenna light goes on. Previously the guy had a cobra 29, bone stock and it was ok.

The coax from what i've seen has some kinks to it so i'm thinking that would be a good start but looking for more experienced people to comment if the coax could cause this issue?

Thanks a bunch!!

 

Thanks for all the input. Yes what it does is rob power from the deck however it is getting power from a factory plug in the back. The cb has constant power where the deck is turned on and off with the key.

If using the cal and swr meter on the cb it's crap, like way above an acceptable level and well above anything acceptable. However I ran with another guy for 2 days, stereo off and he was able to hear me.

I'm going to try new coax today and see what happends.

 

Well, bought some new cable. When removing the old cable i found something id not noticed erlier. One section of coax was severed and just the center core was connected. Replaced the cable and much better now. Stereo functions as it should when the mic is keyed.