Ampsters,
Here is a query from a friend up in the Yukon about a problem he has
with his amp. Can anybody respond?
vy 73,
------- Forwarded message follows -------
With the AL80 on line at
about 350 Watts, in a matter of hours of operation, the filament pin of
the
final burned free at the solder joint and a 3-500Z doesn't work so well
without filament voltage.
This is with a brand new Eimac tube which was given to me and has only been
in
place for a small number of hours of operation. The new tube was sent to
replace
the existing tube that failed. Is it possible that tube failures and also
the
desoldering pins are both associated with the socket being mounted very
close to the chassis and not cooling properly?
I noticed that the pin does not spring well against the pin and adjusting it
does not net a real improvement in pin/socket connection.
I need advice from an amp person... At these 400 watt power levels, I feel
that the root cause must be a poor socket/pin connection and/or filament
over-voltage. I need to order the right kind of socket for that final tube
and if someone who knows thinks it is necessary, I may need to build a
regulated filament voltage supply and possibly make a screened hole under
the
socket to allow the socket pins to cool. I feel the socket must be replaced
with one of better design.
Do you know a manufacturer part number for a better than original
3-500Z socket to be used in the AL-80 amp?
Would it be best to simply repair the AL-80 and sell it to a person who
does not contest or run an amp for hours at a time... and find a good used
amp which is tougher?
Should I use silver solder to fix that tube pin?
Is it possible that the tube that originally failed had its seals burn out
from
overheat because the socket was not cooled properly? Is that
possibly why the filament pin solder melted free?
Please let me know what to do. Please forward the question to another
good amp man. I will order a replacement socket from RF parts, and
silver solder if that is satisfactory, to solder that pin, but people are
warning
me not to silver solder the pin because it will make the tube seals fail.
I hope that soldering that tube pin is not a lost cause. It was such an
expensive gift I would
hate to see it lost.
I know there are a lot of questions here. I would
like the advice of someone who knows this stuff.
------- End of forwarded message -------George T. Daughters, K6GT
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