HP HP-41 C Assembly instructions

HP-41 C repair guide
A simple instruction to get a HP 41C working when battery contact strip is broken.
Requirements:
A small size screw driver
Aluminium for connecting the batteries
Two wires for minus / plus connectors
Cohesive scotch

The HP 41C calculator not working anymore

The broken strip (battery corrosion).
This strip can still be used to connect external modules !

1. Open the case by removing the four screws on the back of
the calculator (you may need to remove the rubber which
covers the wholes)
2. Contact the minus whire with the third copper contact
from the left and the plus wire with the 11th copper
contact on the main board of the calculator by using the
scotch.
Remark:
The main board of the calculator has 21 copper contacts.
The third from the left is the minus contact, the 11th is the
plus contact. Other contacts are used for connecting
additional modules.
(see picture to the right)

3. Connect the minus contact to the right–most battery by
using the aluminum.
4. Connect the plus contact to the left-most battery by using
the aluminium.
5. Use aluminium to connect the second and third battery
Remark:
The connector between the both batteries in the middle
connect the four batteries in serie.
Attach the cover back with the screws
The broken connector still helps to connect the wires to the mainboard
contacts. When the back cover is attached to the calculator again, then it
presses the wires down on the mainboard contacts.
5
4
3

Press the ON button –you’re HP41C calculator is back working !

Contact:
stephang (at) bluewin.ch