HP34C Repair

[burkhard]

(10-29-2018 07:00 PM)javico Wrote:  Hi All,
I'm the proud owner of an HP-34C which was in pristine condition till last week. Unfortunately now for some reason, some keys are unresponsive, and the unit is responding erratically without working correctly. I've tried with a new set of batteries, but the issue is still there.

The Spice series, including the 34C, tend to suffer from a common design problem. In its wisdom to be clever with manufacturing, HP did most of the Spice production without actually soldering the main chips to the board. They are merely held pressed in place. Over time (and these things are 40 years old) dust, dirt, crud, and oxidation gets on the contacts which compromises this bit of genius in ways that would never bother chips soldered on.

Occasionally my 34C acts a little nuts also. I don't particularly want to take it apart if I don't have to (that is supposed to be a little tricky on the Spices...haven't tried it yet. I have found though that if I told the display end in one hand and the other end in the other hand and then give it a little twist (not enough to risk breaking anything, just a bit of torque on the long axis), that "fixes it" for a week or so.

Something to consider and test, if you like.

HP *eventually* started soldering the chips in, but most of them (I think...) are made the other way, so plenty get a little flakey as they age. But don't we all?

Sorry, no idea on a good source for service.