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FT 101ZD troubleshooting, repair & maintenance

Aug 16th 2013, 12:22

tcheek

Joined: Jun 29th 2012, 12:35
Total Topics: 0
Total Posts: 0
I have a 101ZD and I am replacing the finals, I need some insight into neutralizing the 6146B/W GE tubes. All help is appreciated.
Aug 16th 2013, 15:12

WB1GCM

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Please make certain that you follow all safety rules, since you will be adjusting a control in an area with voltage that will kill you!

Use a non conductive screwdriver; keep one hand behind your back!

Neutralization is done on 10 meters. Replace the finals and look for a single, even, deep dip in the final plate current. This is done by adjusting the "Plate" control, with the "Load" control at or near minimum.

If there isn't an even dip, note the position of the neutralization control first, then adjust the neutralization control only a little bit one way or the other. You should be able to attain the desired dip in the plate current with a new set of tubes.

Expect only 70 to 80 Watts RF output on 10 meters; that is fairly normal for the ZD. I ran such a transceiver from 1979 to 1992. A band switch failure prompted me to upgrade to solid state with the FT-990, which is still running in my shack, doing digital duty.
I only replaced the finals once in the ZD. My wife earned DXCC with it.

Bob Allison
WB1GCM
ARRL Test Engineer

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