[Kenwood] TS930 output power - help please

[Wies SP8SW]

My trusty 930 fails again...

I am working CW.
On bands up to 14MHz I have full output, controled by ALC level (CAR pot).

Above this (18..29MHz), I have zero ALC indication on the meter.
With CAR pot I can have only abt 80...40W (indicated on the trx meter).
Current Ic indication is decrasing with band (so as power) - from abt 8A on
14MHz to abt 3A on 28MHz.
AT unit seems working properly (tunes on all bands !). Working on dummy
load - same efect, so not antenna matter...

I do not observe any smoke and other disasters.
I cleaned some connectionns on Signal Unit - no success..

What can I do more ?

Thanks in advance for any help.

73' Wieslaw SP8SW (ex SP8NTW)