View Single Post
  #1   Report Post  
Old October 18th 03, 09:01 PM
M1JDK
 
Posts: n/a
Default Icom AT-500 problem ???

Hi all,

Recently bought an almost new ATU as above, but have just tried it with a
bit more power than the IC-751A delivers by using a Zetagi B300P amp on
14MHz (tested before connecting up with a dummy load and got about 175W for
8W in).

Problem is, when I opened the trimmer inspection lid to tweak the trimmers,
I noticed a funny smell - that acrid one of a transistor burning... I'd
only keyed up for maybe a minute in total.

It still seems to work OK, although it doesn't seem to tune in the bottom
end of the 14MHz band quite as well as it used to, and when I opened the
lid, the smell seems to be concentrated around the left of the motor control
board, behind the front panel. No sign of any bubbling components, and
having let the air circulate, the smell has died down.

Any ideas ? I had thought (in hope) that perhaps it was the big tuning
capacitors getting warm for the first time or similar, but the sod's law
isn't that kind! I've removed the amp, and given up on that idea, but do
you think I should investigate further, or leave well alone and keep my
fingers crossed ?

Thanks for any help,
Mark - M1JDK
UK

PS. Replies via email would be appreciated to 'spitfirecbs at v21 dot me dot
uk'