after repair of broken screw posts my HP-41CX (coconut) runs very satisfying, almost without any problem. (I can’t say if the below mentioned problem existed before, I haven’t used the CX for years).
BUT - the time in the CX runs much faster than it should. One minute standard earth time means 2:56 minutes in the CX universum. With this big delta to the real time the Correct function does not help. Did anyone came across this problem? Does anybody has a hint what can be the reason?
All commands of the Timer Module U11 work correct, no problem at all (Date, CLKT, DDAYS, etc), thus I hope that the problem is outside of the U11 (HP Part Number 01LF6-0001)
The Timer U11 uses a crystal / quartz Y1 with a parallel switched resistor R4 (22 MOhm).
Has anybody seen a specification of the Quartz/Crytal (HP Part Number 0410-1381).
In the Service Manual nothing is mentioned.
(Pictures can be found herehttp://www.schwalvenberg.com/de/hp-41cx/108-time-flies-in-my-hp-41cx)
My assumption is that the crystal and R4 are part of an oscillator that provides time information, mainly build into U11, the Timer Module but the quartz could not be integrated into U11.
What can make this oscillator run three times faster than nominal, is itrunning on an overtone due to aging ???
It would be great to get some feedback or hints or ideas from the community.