Posts: 1,162
Threads: 26
Joined: Aug 2005
It might be an easy fault, it might not. All sorts of things can cause an HP41 not to power up.
It's worth checking/cleaning the internal connectors, as that's easy to do and a very common cause of this problem. Take out any modules and the battery pack. Peel off the feet. Under each foot there's a
screw -- undo these next. Then lift off the bottom case. Lift off the centre case (a U-shaped piece of plastic) next.
The logic board is very likely to be a separate PCB in the 41C (41C halfnuts are _very_ rare). It will either just lift off, or be held on by a couple of 1/4" nuts. Undo these if necessary and take off the logic PCB. Take
anti-static precautions (ground yourself with an anti-static wrist strap, etc). Take off the connector that's under the logic PCB.
Clean the pads on the logic PCB and keyboard PCB that contact this connector. Clean the connector as well. Clean the pads on the keyboard PCB that contact the flexible PCB in the bottom case. Clean this flexible PCB as well. Then squeeze the top part of the flexible PCB (where the foam block is), to improve the contact. To clean the contacts, I always use
propan-2-ol (isopropyl alcohol). Then put it all back together and try it.
Incidentally, pleaase don't throw out any older HP calculator (certainly none of the LED models, 41, 75,71, 10 series). There are people who can use them for spare parts to make other machines work again.
