Colin,
My receive problem was due to the T/R relay in my HF-2500. Burnished the
contacts with some paper, and everything is now fine.
This is a 12VDC, DPDT, open-frame relay. What specific relay do you
recommend that I use to replace it? It's a pain to get to and I'd like a
permanent solution. It's no fun calling DX in a pile-up, and then the
receiver goes dead!
Ken AB4JB
----- Original Message -----
From: "Kenneth C. Falk, CCIM" <falk@investusa.net>
To: "Lamb" <k7fm@teleport.com>
Sent: Saturday, August 12, 2000 10:19 AM
Subject: Re: [AMPS] Relays hanging up
> Colin,
>
> My receive problem was due to the T/R relay in my HF-2500. Burnished the
> contacts with some paper, and everything is now fine.
>
> This is a 12VDC, DPDT, open-frame relay. What specific relay do you
> recommend that I use to replace it? It's a pain to get to and I'd like a
> permanent solution. It's no fun calling DX in a pile-up, and then the
> receiver goes dead!
>
> Ken AB4JB
>
> ----- Original Message -----
> From: "Lamb" <k7fm@teleport.com>
> To: <amps@contesting.com>
> Sent: Saturday, August 12, 2000 10:06 AM
> Subject: Re: [AMPS] Relays hanging up
>
>
> >
> > The TS-430S sometimes suffered from intermittent receive conditions, due
> to
> > the failure of the contacts in the receive bandpass filter. The
> recommended
> > cure was to run a small amount of dc through the relay contacts. This
> same
> > solution can be easily adapted to the relays used in amplifiers.
> >
> > Since the rf can be ac coupled through capacitors, the dc can be run
> through
> > the contacts at the same time the rf is being switched. Large open
relays
> > are used in amplifiers because they are relatively cheap, generally
> trouble
> > free and easy to clean the contacts. Most of the time, the relays work
> > fine. They just need to last as long as the operator. If they continue
> to
> > work, leave them alone. If the receive contacts generate a high
> resistance,
> > and if you do not want to open everything up and clean them, you can
> prevent
> > further problems by switching a dc voltage through a resistance and/or
rf
> > choke, and use a capacitor to couple the rf. The choke and resistor
> > combination must have enough total impedance to decouple the 50 ohm rf.
> >
> > If the high resistance relay contact does not occur very often, it is
not
> > too bad to open the amp up, clean the relay contacts, oil the fan motor,
> > clean off the dust, look to see if the hole in the tube plate is
growing,
> > praise the suppressor and generally see if the high voltage bleeders are
> > still functional.
> >
> > Colin K7FM
> >
> >
> > --
> > FAQ on WWW: http://www.contesting.com/FAQ/amps
> > Submissions: amps@contesting.com
> > Administrative requests: amps-REQUEST@contesting.com
> > Problems: owner-amps@contesting.com
> >
>
--
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