>
>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!
Open frame relays are not fast enough to avoid hotswitching with a modern
radio. The parts for the high speed switching mod on my Web site cost
less than $60 total. See Figure 7B. No user has reported an
intermittent problem with the Matsushita rhodium/gold contact reed relay
we supply. .
>
cheers, Ken
>
>----- 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
>> >
>>
>
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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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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