[Amps] L4B Caution

[Jim W7RY]

And provide the ALC voltage. If you don’t use ALC (which  I don't) then you 
can remove them.

73
Jim W7RY


-----Original Message----- 
From: Paul Baldock
Sent: Thursday, July 25, 2013 10:41 AM
To: Ed K0KL ; amps at contesting.com
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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