[Amps] AL1200 weak receive

[Ed Swiderski, KU4BP]

Thanks Mark. I'm letting it the amp sit right now to discharge as it was 
on today

On 7/29/2022 5:49 PM, Mark Bitterlich wrote:
> You could also go to "operate" and verify that the voltage is the same 
> on both sides of the relay.  If it is NOT the same, you've got a path 
> to ground that is partially pulling the relay in.
>
> Yes, just a WAG, but if you feel the relay contacts and spring are 
> both good, this is all it can be.
>
> Famous last words.
>
> Mark
> wa3jpy
>
> -------- Original message --------
> From: Mark Bitterlich <markbitterlich at embarqmail.com>
> Date: 7/29/22 5:45 PM (GMT-05:00)
> To: "Ed Swiderski, KU4BP" <ku4bp at triad.rr.com>, amps at contesting.com
> Cc: markbitterlich at embarqmail.com
> Subject: RE: [Amps] AL1200 weak receive
>
> Try unplugging the PTT line from the amp and see if the problem goes 
> away.
>
> Sounds like when you are going to "operate" on the front panel, there 
> is a path to ground from the relay coil. Either inside the amp, or the 
> PTT cable going to the radio. To confirm you could unsolder one side 
> of the relay coil, etc.
>
> Mark
> wa3jpy
>
> -------- Original message --------
> From: "Ed Swiderski, KU4BP" <ku4bp at triad.rr.com>
> Date: 7/29/22 12:33 PM (GMT-05:00)
> To: amps at contesting.com
> Subject: [Amps] AL1200 weak receive
>
> I have a confusing problem with my AL1200. During operation when the
> stdby/oper is on, the received signal is very weak. Switching back to
> standby and the signal level is fine. Checked the relay and it was
> operating correctly. Engaging with 12v applied to it. With no power to
> the amp and a rx signal going through, manually engaging the relay
> weakens the signal. Releasing it and it's back to normal. Cleaned the
> contacts using the method described by W8JI on his site. Still no go.
> Stumped on where to look next to track this down. A tests on another
> radio produced the same results.
>
> With no power to the amp, I connected my RigExpert analyzer to the "RF
> in" and a dummy load to "RF out". Doing a sweep, the SWR reads around
> 1:1. Engaging the relay by hand shoots the SWR very high. Goes back down
> when released.
>
> That's the best symptoms I can give. Any suggestions would be an immense
> help.
>
> Thank you,
> Ed KU4BP
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