Re: [Amps] AL1200 weak receive

["Ed Swiderski, KU4BP" <ku4bp@triad.rr.com>]

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<radio.ku8l@gmail.com>  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<jimw7ry@gmail.com>  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" <
> > ku4bp@triad.rr.com> Date: 7/29/22  12:33 PM  (GMT-05:00) To:
> > amps@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_______________________________________________Amps mailing listAmps
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> > Thanks and 73, Jim W7RY
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