[CQ-Contest] Advice about HF amplifiers

Pete Smith n4zr at contesting.com
Mon Sep 6 09:39:37 EDT 2004

At 03:01 AM 9/6/2004, jukka.klemola at nokia.com wrote:
>TL922 cooling is compromised.
>The socket of the 500Zs do not get sufficient air flow.
>Phenomena: the solder inside the filament pins melt.
>Cure: just re-solder but add a fan.

It appears, from my experience, that adding a muffin fan somewhere on top 
of the amplifier (in my case an SB-220), exhausting hot air from inside, is 
sufficient to solve this problem.  I used a pair of 110V muffins connected 
in series across my 110V supply, so that they turn a little more slowly; I 
use the other one to pull air off the transceiver heat sink.

73, Pete N4ZR
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