Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Tom -
That is probably the case. I have also seen a gassy 6EV7 tube cause
the relay to either not drop out - OR - drop out "gently", preventing
the contacts from their normal "wiping" action.
IF the problem is the relay contacts, a drop of DeoxiT on them will
clean them up for another 30 years. Do NOT use a file or abrasive of
any kind. If they're bad enough to need that, you're better off to
replace the relay.
Also, if you DO replace the relay with a new one, examine the contacts
and ensure that the "antenna" contact closes before the "keying"
contact. If it doesn't, GENTLY bend the antenna wiper arm SLIGHTLY so
that it does. This will enhance the life of the antenna switching
contacts of the relay.
73, Garey - K4OAH
Atlanta
Drake C-Line Service Manual
<http://www.k4oah.com>
Tom Taylor (MSTV) wrote:
An intermittent problem I see with my R-4 & T-4 (the xmtr without a VFO)
pair is after transmitting, the receiver is often practically deaf. A
few clicks of the key or mike switch to trigger the relay often fixes
the problem. My theory is that the contacts on the relay, particularly
the antenna switchover contact, needs cleaning. Perhaps replacing the
relay with this recommended replacement will solve the problem.
Tom N7TM
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Garey Barrell
Sent: Wednesday, September 28, 2005 8:29 PM
To: DW Harms
Cc: [email protected]
Subject: Re: [drakelist] T-R relay
Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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Dick -
Why are you wasting time with EBay? You can buy a new relay, Potter &
Brumfield R10-E1Y4-V2.5K, which is the standard relay in all the T(R)-4
(any) transmitters.
The original Varley relay had a 15K coil, which meant very fine wire.
There was a fairly high failure rate caused by the wire breaking,
possibly because of the heating and cooling cycles of the transmitter.
The only change necessary to use the 2.5K ohm relay above is to add a
1.5K, 1/2W resistor in series with the coil.
They're available from both Digi-Key and Mouser for about $15. They're
also available from Newark, and probably their Farnell division in EU.
73, Garey - K4OAH
Atlanta
Drake C-Line Service Manual
<http://www.k4oah.com>
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