RM KL203 Amplifier issue

[Tanker]

So, I'm having issues with my 100W amp. When I unkey, radio doesn't receive until I turn the amp off. The first amp did this and now the second amp is doing the same thing. Amp is in AM position. I did not try SSB position. Seller said they checked amp before they shipped it to me. I have a Cobra NightTracker with Ranger noise cancelling mic. Cobra talk back extension speaker center of the dash. I unplugged the speaker, no difference. Stryker magnetic mount antenna, (SWR Ch1 is 1, SWR Ch 40 is 1.2), in the center of the Silverado double cab roof, cable comes back the roof, down passenger's side of rear window, into cab thru bottom of passenger's side rear door, under mats, between passenger's seat & console to radio. Cable is held in place with double face Gorilla tape. No issues with crimped or exposed coax cables. Radio and amp have their own 10 gauge wires from the battery + & - posts. I moved ground wire of amp to a bolt thru the fender, no difference. I have 2 foot jumper cables from the radio to amp & from amp to swr meter. I removed the SWR meter from the circuit, no difference. No cables are crossed or coiled. Radio dead keys 3 watts. I tried longer jumper cables, no difference. I attached a video so you can hear me key up, release and when you hear sound again, I had turned the amp off.
UPDATE, (Radio goes to amp, amp goes to SWR meter and SWR meter goes to antenna). when I key up, I have 80 watts. When talking, power fluctuates between 70-to 80 watts. When I unkey, needle shows 15 watts until I turn the amp off.

[MDYoungblood]

Thank you for being very clear on the problem and what you have tried so far. It sounds to me that you are having a CMC (common mode current) problem causing the amp to stay keyed. Try a length of coax between the radio and amp that you can make an air choke of 5 turns, 4 1/2” in diameter, and try it with and without the SWR meter inline.

3’s

Greg

[Tanker]

Thank you for being very clear on the problem and what you have tried so far. It sounds to me that you are having a CMC (common mode current) problem causing the amp to stay keyed. Try a length of coax between the radio and amp that you can make an air choke of 5 turns, 4 1/2” in diameter, and try it with and without the SWR meter inline.

3’s

Greg

Thanks Greg, I'll try to make it today.

[Tanker]

Tried both, neither made a difference.