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I have a home brew HF amp using a pair of 3-500z's. The amp is now 14 =
yrs old, and the tubes need replacing. I understand that Eimac no =
longer makes these devices.
1) Our local radio supplier has tubes in unmarked boxes with =
"International Service Master" printed on the tube. Does anyone know =
who makes this component or whether the quality is up to standard?
2) Out of interest, the problem with the old tubes is one of gassing. I =
left them unused for a period of about 5 years. Although "soaking" has =
improved one tube, the other still glows blue on RF envelope peaks, and =
seems to overheat. The problem is much worse on 160m than any of the =
other bands. Does anyone know why this should be?
73, Greg, ZS5K
(new subscriber)
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<DIV><FONT color=3D#000000 size=3D2>I have a home brew HF amp using a =
pair of=20
3-500z's. The amp is now 14 yrs old, and the tubes need =
replacing. I=20
understand that Eimac no longer makes these devices.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>1) Our local radio supplier has =
tubes in=20
unmarked boxes with "International Service Master" printed on =
the=20
tube. Does anyone know who makes this component or whether the =
quality is=20
up to standard?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>2) Out of interest, the problem with =
the old=20
tubes is one of gassing. I left them unused for a period of about =
5=20
years. Although "soaking" has improved one tube, the =
other still=20
glows blue on RF envelope peaks, and seems to overheat. The =
problem is=20
much worse on 160m than any of the other bands. Does anyone know =
why this=20
should be?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>73, Greg, ZS5K</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>(new =
subscriber)</FONT></DIV></BODY></HTML>
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