[Amps] MLA-2500 problem

[Hardy Landskov]

Bill,
Check the values of the string of resistors in the voltage measuring path. 
Those old carbon comp resistors increase in value with age. I had an old 
Commander amp and that's what the problem was. I bought new resistors that 
were HV rated also from Mouser. They have a page with high voltage resistors 
listed. Of course, I hope that's what the problem is.
73 Hardy N7RT

----- Original Message ----- 
From: "BILL KENNAMER" <k5fuv at prodigy.net>
To: <amps at contesting.com>
Sent: Wednesday, August 20, 2014 4:02 PM
Subject: [Amps] MLA-2500 problem


>I have what I consider to be a strange problem with my MLA 2500.
> First, I should mention that it has been in storage for several years, and 
> it's obviously over 30 years old. It shows only 800V on the meter. My 
> first thought is power supply, and my second thought would be old filters. 
> But, in my past experiences with amp power supply failures, they are 
> usually accompanied by a lot of smoke and noise, along with blown fuses.
>
> The time delay does seem to work, as near as I can tell.
>
> Anyone have any thoughts? Also, I'm thinking that if I replace the 
> filters, maybe an increase from 150uF to 220uF or so might help voltage 
> stability. Any suggestions?
>
> Bill K5FUV
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