suggestions for HP-34C disassembly


Good evening folks,

I have an HP-34C which I would like to resuscitate.

I need to replace the battery pack (original) which is almost completely dead, but found reference to appropriate replacements from Digi-Key on the web site, so am going to order same.

More importantly, the calculator often starts functioning in program mode even when the switch is set to Run; I think something's come loose or perhaps shorted.

However, when I tried to take the case apart to check things out, I can't get the case halves separated at the bottom edge, nor have I found any good hints about how to do this, just some passing mentions that it's tricky. :)

If anyone can offer a suggestion, I would be most appreciative.


-- Patrick Woolsey <>


This one works very well:

Just watch out that when it pops, you can tear the flexible interconnect if you don't limit the downward travel of the case back.

If that doesn't work for you, try this:

Edited: 10 Mar 2004, 7:59 p.m.


My case was completely resistant to the first method, but the dental floss technique worked like a charm.

Thanks very much (and also to Luiz and Karl if they happen to read this)!

Now that I've got the calc apart, can see that the switch contacts have a lot of gunk built up; hopefully just cleaning them off will suffice. Keeping my fingers crossed..


-- Patrick Woolsey


Pat --

Good to hear the technique worked well for you. My thanks also to Randy for posting it.

-- Karl


Clean the circuit board area and the contact strips well with alcohol. Then slightly bend out the little contact strips to retension them... make sure each end is level with the other. Place a small amount of contact grease (I use Permatex SuperLube or Radio Shack Lube Gel) on the circuit board contacts.

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