Hi, Herbert;
for what I can think of possible faults:
1 - Power board with faulty component - If I am not wrong, all C-type Spices (HP33C, HP34C and HP38C) have a few extra components in the power board to provide continuous memory; some contributors in here (I remember Katie Wasserman as a first reference) have already dealt with this power board and they may give you guidance;
2 - IF the calculator has already been opened AND it is a solderless Spice, chances are that it's been disassembled and reassembled with the ROM/RAM chips out of order. The fact is that the HP34C has at least one RAM chip and this chip must be positioned in the correct "chip slot", otherwise you'll always have a [Pr Error] when you turn it off and on again. No damage if the chips are mounted following the correct orientation, but if the "privileged" chip mounted in the "continuous power supply" position is a ROM chip instead of the RAM chip, then... [Pr Error]!
Have you performed the [STO][ENTER] internal test? If not, please do it, and check for a
[-8,8,8,8,8,8,8,8,8,8,]
display. If you need guidance to open the calculator and check for this possible fault, let us know.
BTW, there are two major Spices' assembly types: the solderless (main logic components touch a flex circuit board in a "sandwich"-like assembly) and the soldered one (main logic components are soldered in a regular PCB). The best way to know which type is yours is by comparing: the soldered-type units WITH batteries are about the same weight the solderless-type units WITHOUT batteries, because they have an extra rigid metal plate to assure flex-circuit "physical linearity", if I can say so. Another way to compare is by carefully pressing the keys. Keys in soldered-type units move just a little bit in order to operate, while keys in solderless-type units almost level themselves with the keyboard faceplate to operate. If you can compare different units, it's easier to "feel" the difference.
I know that by tracking serial # it is possible to check for internal construction type, but I have no information about serial numbers, sorry. Anyway, the back case of any Spice fits in any other, so if the calculator has already been repaired or refurbished outside HP, there's no guarantee that the serial number actually follows internal construction.
I hope I did not confuse you; if so, forgive and post again, so we can find a better way to help you.
Cheers and success.
Luiz (Brazil)
Edited: 22 Mar 2004, 2:05 a.m.