"Al Parker" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Hi Garey & Andy,
Thanks for the ref. to my cap rebuilding page (that Ron has on his
site). If anyone doesn't want to go thru the procedure themself --
I've been rebuilding 2 & 3 section caps for R-390A guys, for $50/set of
2 plus postage. Will do the Drake C129/140 can for same price, $25 plus
return postage. I prefer to do more than one at a time, and will give a 10%
discount for 2 or more at a time.
I can do this basic process for many multi-section cans, 3-section and
higher voltages might be slightly more cost, let me know what you have or
need & I'll figure a cost.
This is all based upon you sending me your good, re-useable can. I
don't have enough on hand to offer an exchange or outright sale at the
moment.
More info on the process can be seen at:
http://www.boatanchors.org/filtercap.htm
(but I find that the server is temporarliy in a grouchy mood right now
Try it later tonite.)
73,
Al, W8UT
New Bern, NC
www.boatanchors.org
www.hammarlund.info
----- Original Message -----
From: "Garey Barrell" <[EMAIL PROTECTED]>
To: "Drakelist" <[EMAIL PROTECTED]>
Sent: Sunday, August 12, 2007 4:32 PM
Subject: Re: [drakelist] Fine burble on T-4XB note -the fix!
Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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Andy -
Great! Sorry I didn't mention the C140 part. I really wasn't up to the
"replacement" point yet. You jumped ahead! :-)
Your symptoms plus the keying adjustment improvement indicates that the
problem was most likely the bias cap in the AC-3. Good to replace it
though, since that's the one electrolytic that can destroy finals, power
supply and/or transmitter if it fails, even if just in standby. The rest
are probably not far behind either, so cheap insurance. If that blue cap
bothers you as much as it does me, you might want to take a look at:
<http://www.wb4hfn.com/DRAKE/DrakeArticles/TechTips/FilterCapacitorRebuilding.htm>
Frontier Electronics will do this for you for $35:
[EMAIL PROTECTED]
Anyway, it's fixed. That's Job 1.....!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>
Andrew Catanzaro wrote:
Garey,
I bought the AC-4 power supply replacement kit from the Heathkit Shop and
installed it in the AC-3. The burble on the CW note vanished. Now I can
tell with a local receiver that the note is great.
While I was at it, I replaced the electrolytics on the chassis of the
T-4XB. Only after I physically removed C129, did I realize the can also
contained C140. Found a 150 uF 450 volt cap that Crazy-Glued into the
opening left by removing the can and found a smaller electrolytic to hang
under it to replace C140, and looks like the CW semi-QSK keying
adjustments aren't so critical (VOX level and VOX delay). (I know, a
computer-grade blue plastic electrolytic's appearance is anathema on the
surface of that vintage copper chassis, but hey, it works!)
Thanks for your help!
73,
Andy W9NJY
Milwaukee WI
----- Original Message ----- From: "Garey Barrell" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, July 29, 2007 11:43 AM
Subject: Re: [drakelist] Fine burble on T-4XB note
Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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Andy -
Most likely power supply ripple. There are not many good caps left in
AC-3s after almost 50 years.
Since you are able to replicate the burble locally, you could try
bridging a good cap across the can cap in the T-4XB itself (C129), and
the output cap (C5b) of the bias supply in the AC-3 (watch polarity!).
Those are the two most likely troublemakers. If neither of those affect
the burble, you could try to bridge the output cap of the LV supply
(C4b).
If bridging the caps in the AC-3 resolves the problem, you might want to
consider the AC-4R from The Heathkit Shop. It replaces everything
except the transformer and bias pot.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>
Andrew Catanzaro wrote:
"Andrew Catanzaro" <[EMAIL PROTECTED]> made an utterance to the
drakelist gang
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I have recently gotten a Drake B-line operational and am very happy
with it. The R-4B is a fantastic receiver. I have built two Norcal DDS
VFO's to replace the PTO's and it's great having frequency resolution
to the last Hz and no drift.
A friend with good ears and who lives close by told me that there is an
irregularity on my CW note. People far away tell me my note is fine.
I took a separate receiver and used only a dummy load on the
transmitter and a dummy load on the receiver so it would not be
overloaded. I can hear the raspiness or burble. It's like a fine
modulation on an otherwise great CW note. Going back to the original
Drake PTO does not fix the problem. It sounds exactly the same. I
swapped out all the tubes for NOS, and there was no change. I am using
an AC-3 power supply with the original caps. There is nothing that
sounds like AC hum on the signal. Is this a normal observation of the
T-4XB's CW note or is there something wrong? Except for my friend four
miles away, and my own observations, all comments on the Drake's signal
have been unqualified positive remarks.
I listen to my K2's CW note in the same test receiver with the same
dummy loads and the K2's note is absolutely pure.
Any comments or suggestions greatly appreciated!
73,
Andy W9NJY
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