Oh, super!
I dubbelchecked the circuit and everything is connected like it should.
Whith the 10-pole connector unpluged I've measured the resistance between pole A (gnd) and pole F (mid-pin of potentiometer).
footpedal unpressed gives about 0 ohms
footpedal pressed around 1k7 ohms (because of the other resistors it is less than 2k5).
This in a linear way as the pedal is pressed.
It would be nice if you could measure that! @Dutch Welder
Between A and F on my RCT-F (TR-52 board):
Footpedal unpressed I have a high resistance, like 40-60 kOhms.
Then it drastically drops at the beginning, but alone it's not easy to measure.
Fully pressed, 1.7 to 1.9 kOhms.
Poti is 2.2 kOhms.
Thank you so much @Macfun !
I'm gonna check this circuit with what i've got.
although there is one thing that does cought my eye when checking the resistor values:
that is, the third resistor from the top, see images below:
when read from left to right it would give you a value of 2,12 mega ohms with an insane tolerance of 0,1%... this is not likely!
When read from left to right it gives 17,4 K ohms @ 1% tolerance, which is more likely to be truth.
However, in the previous circuitery this should be a 22,1 K ohm!
(the other values look the same: r2 = 56k
r1 & r4 = 1k9 or 1k8 wether the second ring is white or gray).