Time flies in my HP-41CX

[Drulli]

Problem is solved!

Waiting for the ordered but not yet delivered components (Y2 and R4), I refurbished my card reader ("gummy wheel problem“) in the meantime.
I put the refurbished Card Reader in the CX, the reader was listed in Catalog 1, so far so good.
When I put a first card in the reader the power sucked by the engine led the CX lost its memory. The reader needed 2,3 attempts before the cards could be read without problems.

The clock in the CX, which ran 3 times faster than it should, is now running very precisely with the right "speed".
The power loss must have reset some internal states in the Timer IC (U11) which must have become somewhat scrubby in the initial power up phase of the reassembled CX.
At least that's my assumption and by far the best root cause!