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Re: [Amps] Alpha 77 start up

Subject: Re: [Amps] Alpha 77 start up
From: Jan Ditzian <>
Date: Wed, 02 Mar 2011 22:22:53 -0500
List-post: <">>

The relay which seems not to work is K5, the vacuum relay.  I have 
ordered one.  The problem is that, as I check continuity, none of the 
poles are connected to each other.  This means that the SPDT relay is 
actually a 0PDT (no pol, double throw) relay.  I think this is the 
problem.  If you look at the schematic, which appears to be in the state 
of amp standby or off, if nothing is connected to anything at K5, then 
the HF input goes nowhere.  This is exactly what happens: with the amp 
off, exciter connected to amp input, dummy load connected to amp output, 
I have high swr on the exciter.  With this configuration, the exciter 
should be looking at the dummy load, and the amp should be passing it 
through.  K4 would normally be open at this point anyway, so I did not 
try to figure out what it did.  I believe that K5, which I think is the 
QSK T/R switch, not only does not switch, it is completely burned out, 
so it does not even pass anything in the off position.

Jan, KX2A

On 03/02/2011 09:37 PM, wrote:
> Jan,
> You were talking about an input relay in line #4 of your 2/28 e-mail.  
> The relay you are describing is K5, a vacuum relay, and is a 
> SPDT output relay.  The input relay, K4, a SPST is a reed relay.  Mine 
> is tubular and yellow.  I think you are looking at the wrong device.  
> Something doesn't seem right.
> Bob
> In a message dated 3/2/2011 12:07:56 P.M. Eastern Standard Time, 
> writes:
>     I tried to operate the relay from a 24 VDC supply, but all I ever got
>     was a spark.  No relay sound or indication that the relay had
>     operated.
>     I ordered a replacement HC-1 24 volt relay from Max Gain systems.
>     It looks like this going to be a project to remove and replace.  Has
>     anyone done this?  I would like to know if the relay must be
>     unscrewed
>     and removed from the top.  If so, then I must unsolder the bottom
>     connections, the operating poles, from the bottom through the hole in
>     the circuit board that is over the relay when viewed from the bottom.
>     Is the panel tapped, or is there an anchored nut, or is the nut
>     free, so
>     that I have to hold it with something on the bottom when
>     unscrewing it
>     from the top?
>     Any other suggestions about this replacement are welcome.
>     Jan, KX2A
>     _______________________________________________
>     Amps mailing list

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