------------ ORIGINAL MESSAGE ------------(may be snipped)
On Wed, 20 Apr 2016 15:55:21 +0000 (UTC), Howard wrote:
>I've acquired a near mint low usage commander HF2500. Amp works great, output
>is what it should
>be. It was originally purchased in 1993. My question is about the capacitors
>in the power supply, should I replace?
>Howard
REPLY:
Howard, I'm sorry I can't answer your question but I can offer some
advice based on a bad experience (twice) with that amplifier. They
like to advertise it as a legal limit amplifier, but that is true only
for CW and SSB, not for RTTY or other continuous carrier mode.
There is a toroid transformer in the plate tank circuit which will
burn up if operated at 1500 watts RTTY on 7 MHz and lower frequencies.
The first time this happened to me I thought it was just a fluke, but
it happened again. After a conversation with the factory, they advised
me to hold the power down to 1000 watts on RTTY. In fact, they
admitted this weakness is the main reason they developed the Magnum
version of the amplifier. Unfortunately, the Magnum is for export
only, as I am told. I have seen them for sale in the US, apparently
smuggled in. My information on the Magnum is a few years old so it
could have changed.
That toroid is not in the circuit at 14 MHz and up, so there is no
problem running legal limit there.
Aside from that issue it is a great amp, although very hard to take
apart for service. I hope you never have to change the lamps in the
meters or you'll see what I mean.
I just saved you a couple hundred bucks. You're welcome. :-)
73, Bill W6WRT
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