"Dennis Monticelli" <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- I'm going with the flow and say "bad caps." I have a recapped L7 here in the shack running off 120V at the end of a long run thru the house. I typically load it to 400 or 500W on the CW (lower HV) setting with at most 50W of drive. While I haven't measured the line sag, I would guess it runs 5 to 10V judging by the slight dimming of the lights.
BTW, a slow turning fan placed on top of the power supply cage does wonders for drawing out heat and probably increasing longevity in the process. Dennis AE6C On 3/27/06, Garey Barrell <[EMAIL PROTECTED]> wrote: > > Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang > ---------------------------------------------------------------------- > 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 > > ---------------------------------------------------------------------- > > 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 > ---------------------------------------------------------------------- > Submissions: [email protected] > Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body > Hopelessly Lost: [EMAIL PROTECTED] - help in body of message > Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- Submissions: [email protected] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net ----------------------------------------------------------------------
