Re: Repair of I/O ass'y on HP-41C

[Christoph Klug]

Please describe the forum the technologie you use for repairing the I/O assembly.....

[Dave Mabry]

Repairing the I/O assembly in the HP-41C series is generally a matter of some fairly small soldering. I use a binocular microscope with a high quality fine tip temperature controlled Metcal soldering iron. Here are a couple of examples of repaired assemblies. The first one was fairly easy, the second one was quite trashed. I have done worse ones, just didn't think to take a photo. I have to scrape the plastic coating off the copper foils to expose a surface to solder to. Then I use some copper foil with adhesive backing, cut to size, and solder it to the assembly. So far I haven't found one that I couldn't repair, and one required the copper foil to extend all the way to the point where the assembly makes contact with the PC board of the calculator. That one was a challenge, but it works fine.

This one had only one of the four contacts that didn't work.

All four contacts were trashed on this one.

These are just two examples. I am certainly willing to help anyone repair their own. Feel free to e-mail me directly or ask questions here. I will also do the repair for $20 to $25, depending on the severity of corrosion.