Yes. Sorry i didnt make that clear.
73
Mark
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No Problem Mark.
I just wanted to make sure all knew there was a different model number
for the Dual impedance 444's
I've not seen one with any kind of gain pot in them--maybe yet another
variation.
Curt
KU8L
On 2/20/2012 9:27 AM, Mark Nace wrote:
Yes. Sorry i didnt make that clear.
73
A timely question about the L4/L7 bleeder resistors. I recently had an issue
with one of my L4PS supplies. It turned out to be a bad cap which I replaced.
I'm going to install a Heathkit Shop board eventually but I wanted to get the
amp back on line for use in the ARRL CW DX contest. While the
I recently aquired a l4b. I upgraded the ps and soft key with harbach. I
turned the amp on in ssb with no load and have 2400 volts. I did not try
and key or do anything else as i do not want to cause damage. I believe i
should have 2600volts.
73 marc hs0zju
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Just like most of us...Age :-)
73,
Lee
-Original Message-
From: GALE STEWARD k...@yahoo.com
To: Dino Papas k...@cox.net; Mail List - Drake Gear Drake Gear
drakelist@zerobeat.net
Sent: Mon, Feb 20, 2012 10:30 am
Subject: Re: [Drakelist] L-4B/L7 Power Supply Rebuilds
A timely
Marc,
What is your line voltage?
73,
Lee
-Original Message-
From: hs0zju hs0...@gmail.com
To: drakelist drakelist@zerobeat.net
Sent: Mon, Feb 20, 2012 10:53 am
Subject: [Drakelist] low plate voltgage l4b
I recently aquired a l4b. I upgraded the ps and soft key with harbach.
I turned
Marc - I just rebuilt the L-7PS with a Harbach board (and a L-4PS with the
Heathkit Shop board)Both boards show 2700 volts on the amp meters after
putting them into operation.
Did you do a low-voltage test before installing? I applied a 20VAC voltage to
the input and got ~50VDC at the
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Stew
Based on your description my expectation is that you had a voltage
breakdown of the bleeder resistor. While we normally think of resistors
in terms of the power they can dissipate, there is a voltage limit that
can be sustained across the resistor as well as from the body to
ground. I
Typically this is due to low line voltage or a HV meter circuit that needs to
be recalibrated.
73,
Evan, K9SQG
-Original Message-
From: hs0zju hs0...@gmail.com
To: drakelist drakelist@zerobeat.net
Sent: Mon, Feb 20, 2012 10:52 am
Subject: [Drakelist] low plate voltgage l4b
I
Stew,
The situation you experienced is disturbing. The failures you experienced are
strange from several perspectives. Why?
Well, first, assuming that the power supply is wired correctly, it is unusual
to have both bleeders open. When one experiences a failure mode of open, the
series
as i do not want
to cause damage. I believe i should have 2600volts.
73 marc hs0zju
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As a side note, a properly wired L4, L4B, or L7 power supply chassis is ALWAYS
at ground potential for safety reasons. The safety ground from the outlet goes
directly to the chassis of the power supply, whether or not the RF deck is
plugged into it or not.
A number of years ago, there was a
Would agree with you about the input AC power, but if you look at
the high voltage the high voltage return side is not tied to the PS
chassis but runs to Pin 6 of the power connector and then in the
amplifier where it is only tied directly to chassis when the
interlock
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On Feb 21, 2012 8:23 AM, funbiz fun...@gmail.com wrote:
The line voltgage here is 230volts and is stable when using my ameritron.
I just opened the ps to double check my work and it looks 100%
Unfortunately i discovered another problem. The cabinet is hot (has
To be on the safe side, bond the amplifier chassis and the PS chassis
together with a suitable length of shield from a piece of coax or similar
cable.
It certainly makes a big difference with the Hallicrafters SR-2000
Hurricane and P-2000 power supply. It is probably not a bad idea with any
John
There is a ground wire in the cable that connects to pin 7 on both
PS and amplifier that ties the chassis together. As I understand
the metering system of the L4B/L7 you will always have the high
voltage return sitting slightly above chassis due to the grid
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