Peter -
I also forget to state what 'everyone knows', which is that the first thing is to go through with a
screwdriver and tighten all grounding hardware. The mounting FEET of the small boards are almost
all ground connections.
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>
Peter Ravn wrote:
Although I strictly follow the tuning procedure described in section B on p. 14 in the
instruction manual, my T4XB has suddenly changed behavoiur. The output power on all bands has gone
down from on average of 100 watts to 45 watts. The AC-4 bias reads .07 on the plate meter when the
gain is fully CCW, and the mode switch is on TUNE. With the GAIN at app. 9 o'clock, the reading is
0.15 A, and with the PLATE control the plate current is dipped - more distinctly on some bands
than others. Increasing the GAIN to maximum the reading is 0.2 A. Alternately adjusting the PLATE
and LOAD controls for maximum RF output, the result is 45 Watts. As before SWR is low, so
apparently the T4XB is able to tune the antenna. But the LOADING control on 80 meters has to
be turned fully CCW to achieve the best result, whereas it before was between 3 and 4, which might
indicate that the tuner doesn't work as it should. Add to that the finals get hotter than before.
So there must be a mismatch. The question is /where/?
73 de Peter
OZ8CTH
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