Placement of chips in HP 34C


I just opened my 34C (the solderless...)to fix some bad connections.

The chips just chipped out and now I don´t know where to put them.. Can anyone please help me?



First you should make us know the id number of each one.




Hi Hans-Erik, Jon;

I have an HP34C and I have opened (and successfuly closed) some solderless Spice's. What I can tell you is that if you look at it with the display in the upper position, all IC's are lined with their terminal (pin) #1 facing up (all of them, including the bigger one).

There are three places where you can mount the small 8-pin DIP IC's. The upper one is the only one that is kept fed while the calculator is switched to off (continuous memory). This is the place where the RAM IC must go. If you place a ROM IC in this upmost position, [Pr Error] will be shown every time you switch your calculator back on.

Take the three small 8-pin DIP IC's and check for their ID. The one with a completely different ID is the RAM IC. There will be two of them with closer identifiers, differing in one or two digits and having a common literal (ALPHA) chain.

If you still need advice (as Jon mentions correctly), post again with the IC's ID codes.

Hope you succeed.

Luiz (Brazil)

Edited: 15 Nov 2004, 2:40 p.m.


Thanks for the tip. I love the Internet, lots of friendly people with good advise out there. The calculator is now running again, but - alas - one (insignificant but irritating) segment is still down and out. As all connectors now are cleaned, I guess the LED module is to blame.

Anybody out there with a LED to spare?


Unfortunately if only one segment of one digit is out, it's almost certainly the display module. It _could_ be the processor chip (the 40 pin one), but that's unlikely.

A display from any Spice series calculator should work.


I have a display (led unit) to spare mail. Drop me a mail if needed at "".



Hi Ronald, you have mail in your inbox...

As I said, lot´s of friendly people out there...


I started this thread and I am happy to close it by telling all who helped me that I am now the happy owner of a perfectly well working HP34C.


I second you in your words about finding good souls in the Internet.

Luiz (Brazil)

123456 to remove

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