Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Evan -
I think you have the right idea. Sounds like one or more caps with a
high ESR. They charge up fine with just the bleeder load, but as soon
as you draw any "real" current the voltage sags to about 1/2. The
other key, as I read the original question was that BOTH voltages drop
to "about" 1000 V, or ~1300 and ~ 950?
Add that the to fact that if they are original those caps are past their
expected lifetime. I bet an ESR meter would show the problem.
73, Garey - K4OAH
Atlanta
Drake B & C-Line Service CDs
<http://www.k4oah.com>
[EMAIL PROTECTED] wrote:
Based upon 30+ years of experience with L4, L4B, L7 amps, wired for
110v and 220v, in multiple locations, I would bet a Starbuck's coffee
that the problem with that great of a voltage sag is due to one or
more electrolytic capacitors failing. For the secondary to sag by
40-50% due to a primary (line voltage) sag, that means the line
voltage would go down to 55-60 VAC. So, any bets?
73,
Evan
-----Original Message-----
From: [EMAIL PROTECTED]
To: Neil Kutchera <[EMAIL PROTECTED]>; [email protected]
Sent: Mon, 27 Mar 2006 15:44:37 -0600
Subject: RE: [drakelist] L7 Voltage Sag
"" <[EMAIL PROTECTED] <mailto:pulsarxp%40earthlink.net>> made an utterance to
the drakelist gang
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It probably means you have #14 house wiring!
Lee
w0vt
> [Original Message]
> From: Neil Kutchera <[EMAIL PROTECTED] <mailto:k4njk%40bellsouth.net>>
> To: <[email protected] <mailto:drakelist%40www.zerobeat.net>>
> Date: 03/27/2006 12:26:21 PM
> Subject: [drakelist] L7 Voltage Sag
>
>
> Neil Kutchera <[EMAIL PROTECTED] <mailto:k4njk%40bellsouth.net>> made an
utterance to the drakelist
gang
> ----------------------------------------------------------------------
> I'm working on repairing my Drake L7 amplifier before I put it up for
> sale. It is set for 110 volts. When I turn on the amp the plate
> voltage reads either 2600 in SSB or 1850 in CW. Under load the it
> drops to 1000 volts regardless of the mode. The amp will run between
> 500 - 600 watts output with 120 watts of drive at this voltage. I've
> tested this with two sets of tubes. Does this indicate the power
> supply caps are in need of replacement? If so can anyone recommend a
> good source of parts?
>
> Thanks,
> Neil
> K4NJK
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