those bleeders also provide the ALC voltage, and cut off bias.
STEVEN GRANT W4IIV
________________________________
From: Paul Baldock <paul@paulbaldock.com>
To: Ed K0KL <edk0kl@centurytel.net>; amps@contesting.com
Sent: Thursday, July 25, 2013 1:41 PM
Subject: Re: [Amps] L4B Caution
I suggest you remove the bleeder resistors. They serve no purpose
other than to speed up the bleed down when you turn the amp off. They
create a lot of unnecessary heat in the supply.
- Paul KW7Y
At 10:32 AM 7/25/2013, Ed K0KL wrote:
>I had a bad experience when working on an L4B for a pal. The bleeder
>resistor mounting
>scheme proved to be a little poor (unusual for Drake). When
>reinstalled, one of the resistors
>shorted to the mounting screw.
>This bleeder is held in place by a screw that goes through the
>center of the resistor. Mica slices
>insulate the ends (chassis and screw head). Only thing is the
>resistor arced through the ceramic
>base material. So I used glass tape to insulated the screw on the
>reinstalled components. This
>provided better spacing to the center of the screw.
>Note- I replaced the resistors, having the same thing reoccur. Only
>with the use of the tape did
>the thing calm down. Ordinary electrical tape won't work as it will
>melt caused by the heat of
>the resistors.
>
>Anyway, that was some time ago, the amp is going strong. Except for
>a rather weak plate
>transformer, this puppy will no doubt last several lifetimes.
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