KN5000 missing notes - every 3rd

[rippledmind]

HI,
turned on the KN5000 and suddenly all F, A and C# do not play!! and clues?

 

[RMepstead]

Possibly accumulated dust under the keys

 

[Mica353]

Not dust. Either corrosion or loose connector

 

[Gourockian]

HI,
turned on the KN5000 and suddenly all F, A and C# do not play!! and clues?

Hi, sorry for the very late response - I didn't see your original post until today. I had a similar issue (different notes) with my KN5000 back in 2014 so, if you still have this problem, this might help.

I found that one of the circuit board tracks on the keybed PCB had broken. It took me a good while to find it, using a magnifying glass but after bypassing it with a 'flying wire', it was back to normal again. You'll probably want to confirm any ciruit breaks with a multimeter set to 'continuity' or 'diode test' and then use basic soldering skills to bypass the break.

If you need it, you can download the service manual here: https://www.manualslib.com/manual/1005851/Technics-Sx-Kn5000.html. It shows how to dismantle the keyboard.