Hi,
To the OP of this thread. Where did you purchase the new tacho from?
You say you fitted a beko one.
Im assuming the oe one is intergrated into the motor and would mean replacing the complete unit, is that correct?
I am having similar issues with my Zanussi zdt21001fa. I originally thought it wasnt heating but it does get warm for part of the cycle but then seems to go on forever.
I have tried the error code reading and it seems i also have 13 flashes so the tacho could be faulty on mine too.
I am yet to open it up and check for continuity at the tacho which will be my next step