Mitchell Chesler <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Thanks for the words of wisdom Garey. This is why I'm not using it
yet - I'm just checking it out for the first time. I'll check the
grounding as advised and a new AC-4 board is a top priority.
There is no "service CD" for the TR-4 is there?
- Mitch
On Jan 12, 2008, at 5:34 PM, Garey Barrell wrote:
Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
drakelist gang
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Mitch -
Frequency jumping is often an indication of bad grounds. If the PTO
doesn't already have the grounding braid from the side of the PTO
gearbox to the lead screw follower, that's a good place to start.
It also is a good idea to go through the entire transceiver with a
screwdriver and make sure that all mounting hardware is tight. Any
that ARE tight, loosen them a quarter turn and then retighten.
Frequency jumping is also a failure mechanism of the oscillating
transistor in the PTO. In your unit it would be a bipolar, probably
a 2N706 if your s/n is less than 27000. If you have a counter or an
external general coverage receiver you can listen to the various
oscillators and see which one is jumping before attacking it!
Drifting bias current is one of the warning signs of Bias supply
problems. I highly recommend the AC-4R board from the Heathkit
Shop. Meanwhile, I would not leave the transceiver on, even in
receive, if you are not in the room.
The relay contacts can be cleaned, but the relay is easily damaged,
and as you know, in a very difficult spot to access.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>
Mitchell Chesler wrote:
Mitchell Chesler <[EMAIL PROTECTED]> made an utterance to the
drakelist gang
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Hello I'm new to this forum - an old newbie: had a TR-3 as a
teenager in 1968, and for old times sake recently acquired a TR-4
that I estimate was manufactured around 1967. It has nice audio and
good output on all bands, but suffers from what I think is a dirty
relay (scratchy intermittent noise, corrected temporarily by
switching briefly to transmit) -- but a greater annoyance is
apparent VFO jumping on both transmit and receive - by a few
hundred Hz. This happens even if the rig is well warmed up.
The AC-4 that powers it is old and will need to be upgraded -
probably with the heathkitshop board. I did notice that the bias,
after being set a week ago, had dropped by about 15-20% and had to
be reset.
Searching the Drakelist didn't point me in any direction so I
thought I'd just ask if there is perhaps a common cause/cure for
the frequency jumps.
Thanks es 73,
Mitch Chesler NB2N
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