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Re: [Amps] AL1200 weak receive

Subject: Re: [Amps] AL1200 weak receive
From: "Ed Swiderski, KU4BP" <>
Date: Sun, 31 Jul 2022 08:37:29 -0400
List-post: <>
Okay. Will look at it again today with your suggestions.

Thank you.

On 7/30/2022 9:34 AM, gudguyham--- via Amps wrote:
No, it is the case!  The ONLY way the rx can be lost if the switch is in operate is if the antenna relay line is 
shorted to ground and the rx signal is fine in standby.  It’s very simple to determine if the antenna relay 
is grounded in operate and that is to check for plate idle current.  That said, if the ptt line is shorted all you 
need to do is pull the ptt line out.  If the rx is restored then the ptt line is shorted or the radio has welded 
contacts or a shorted transistor just like Jim suggested.  If the relay still engages when the ptt line is pulled 
out then the negative side of the relay is shorted to ground inside the amp.  DO NOT go inside the amp unless 
the relay is activating with no ptt line plugged in!!!!!!

Sent from the all new AOL app for iOS

On Saturday, July 30, 2022, 8:59 AM, Curt Nixon<>  wrote:

Don't think that is the case since he gets receive ok when the op switch is
off.  Really needs to isolate the relay coil to see if the coil is shorted
to ground or it is wiring to the jack
Acts the same with relay cable pulled out so not the cable.

On Fri, Jul 29, 2022, 11:17 PM Jim W7RY<>  wrote:

Which would indicate that the relay in the radio has its contacts welded
together (or its transistor or FET shorted).

73, Jim W7RY

On 7/29/2022 4:45 PM, Mark Bitterlich via Amps wrote:
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. Markwa3jpy
-------- Original message --------From: "Ed Swiderski, KU4BP" <> Date: 7/29/22  12:33 PM  (GMT-05:00) To:  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
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Thanks and 73, Jim W7RY
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