HP-71B battery drain with no extra RAM or ROM

[Dave Frederickson]

Later model 71's and those repaired by HP had the spring contacts replaced by a pieces of foam and simple, stamped metal contacts. When you stated that it was not a spring contact, Bob probably thought you were referring to the foam contacts.

The missing contact is normally connected by a wire inside the calculator. If you can't find a replacement contact, I think you could fashion something out of a piece of tin can. However, the calculator still needs to be opened to solder the wire.

The two PC boards inside the 71 are connected by a delicate flex cable that is prone to cracking so if you decide to undertake the repair then proceed with caution.

Further instructions can be found in the 71B Service Manual.

Dave