HP41.org

I have a HP 41C in my collection
When trying it out it functions normally except when putting it off: I get always "Data Error"on the display which I have to clear with the back key, then Off works.
What does this mean??

Mark

Try to remove all modules and see.
You can also take a reset (deletes all data in memory) Holding back arrow while power on.
I have also seen strange problems do to bad connection between CPUboard and Keyboad.

There are no modules
Did already the reset
Problem rest. So hardware problem?

Mark

Is this the old or new model (fullnut, halfnut)
viewtopic.php?f=2&t=3

If its the old version, I have seen often problem with the plastic that hold cpu board. The screw do not press enough do to the broken plastic.

If you look at first picture in the link above, this units has been armored with some nuts.