Dual C844 assistance of the club required

Collegues, I got (from ebay.de) C844 deck with several defects. All bugs exept one are fixed.
One defect remains.
The reset counter, memory and set bnobs do not affect anything.
When looking the electric diagram memory sw pcp is simply 4 knobs with two states: pressed - short sircuit and not pressed - open sircuit.
When in the deck when looking with multimeter situation is different. When knod is not pressed - open sircuit. Bun when the knor is pressed - there is resistance about 10K ohms.
From the other side, when shorting the appropriate contacts with 1.5K ohm resistor - functions (reset counter, memory,..) operates normally.
So please advice, should I exchange the knobs in SW PCB to normal ones withiut resistance?
Also one more question. power transistor on radiator at the control PCB is rather worm-hot while deck is operatind. Is it normally?

Thanks in advance,
Alexander