Fred -
Is the plate meter fluctuating with the power change? A failing carbon
comp resistor can present like this, and the plate meter shunt resistor
sometimes fails in this manner. What does the plate meter show at full
power?
This sort of intermittent can be caused by bad ground connections,
(among other things!,) so a trip through with a screwdriver to tighten
loose hardware can help considerably.
Sudden jumps in power with RF TUNE adjustment can indicate instability,
sometimes caused by poor neutralization of the PA stage, and especially
on the higher bands.
Lastly, operating at that low power will exaggerate any small anomaly as
the transmitter is barely 'turned on'.
Let us know what you find!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
[email protected] wrote:
/Tune up Drake B Line. /
//
/Pre tune using spot settings. Fine tune on antenna with about 10 watts./
//
/Not all the time but some time when peaking the pre-selector on the
receiver the output will drop suddenly or increase suddenly to 40
watts. The output on the Drake MN 2000 watt meter will show a
fluctuation on the meter. Moving the meterback and forth a couple of
watts from the 10 watt setting./
//
/Any ideas? Poor RCA cables? MN 2000 meter circuit? Anyone else ever
see this on the output meter. It just drives me nuts to see erratic
readings like this on the output meter. I get 260 mills on the
transmitter meter so the output seems ok but it just drives me crazy
to have this kind of issue with the rig. /
//
/The rig was gone over a couple of years ago including rebuilding the
power supply and some additional tube replacements. about $400.00
worth of repairs and upgrades. It was working at the time but was
experiencing another intermittent problem. /
//
/Anyone else every experience these kinds of problems with their Drake
B line ?/
//
/Thanks 73 de Fred WD8ADG/
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