It seems to be a problem with intermittent contact in antenna relay or
attenuator, so I wonder if somebody has some experience with softening
voltage for switches and relays?
The relay and attenuator for FT-901/902 is shown on
http://home.online.no/~la8ak/93a.htm
(perhaps somewhat bad quality when you don't know already what it is?)
A simplified circuit diagram is shown. Decoupling capacitors are not
shown. Wonder what sort of softening current is needed for some
improvement? Suppose 13.5V is a practical limit to avoid too much
current transient.

73
Jan-Martin
LA8AK
---
J. M. Noeding, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/c.htm

It seems to be a problem with intermittent contact in antenna relay or
attenuator, so I wonder if somebody has some experience with softening
voltage for switches and relays?
The relay and attenuator for FT-901/902 is shown
=======================
Don't know type of relay in FT-902 .
If contacts can be accessed by removing cover ,try to slide a piece of paper
drenched in contact cleaner a few times in between contacts .
I remember that this method was successful when I had a FT- 400 ( a valve
transceiver from the late 60s) ,my first transceiver which I used between
1985 and 1991 .

Frank GM0CSZ / KN6WH