I have an MFJ 989D that I picked up used. I changed out the flimsy
rotary Inductor with a well insulated ceramic insulated one from an
old military tuning unit measuring 31 uh. It works great.It was
physicially the same size and only took an L bracket made from
Aluminum and the gears line up perfactly for the turns counter. What I
see now and BEFORE the inductor change is above 20 meters, i.e. 15
and 10 meters, while applying 30 watts to tune the antenna, the power
and swr meter pulsates, and then shuts down. I put another swr bridge
into the input of the 989D and it acts normal and I can use it to tune
the antenna with out the pulsating.

Anyone ever seen this problem? The 989D works great as far a tuning
but the SWR indicator circuit seems to have some kind of problem above
20 meters.

Any help would be appreciated..

thanks, John aka W3ZDF