Interchanging IC´s in Spices


Hi, all;

as we all share experiences, here comes one of mine.

A few hours ago I was struggling to make one working Spice of about four different nonworking units. I checked Eric´s marvelous reference page and found that some Spices - HP34C, HP38C and HP33E - share the same processor - 1820-2162 or 1820-2162A. I also remembered reading somewhere (old posts, very old posts...) that although Spices might have processors with same identification, they might not be interchangeable from one model to another (I concluded that the firmware might be different, though).

Anyway, desperate circumstances lead to desperate measures, so after trying different power boards and 'sandwiched' flex circuit, I took an HP38C´s 1820-2162 and tested it with an HP34C´s chipset. It worked well, and I (sadly) concluded that I have at least two Spices´ processors burnt out!

Well, I must confess that the HP34C worked well at least until I assembled the whole unit and realized that I kept an E-series power board inside of it, I mean, the poor thing shows

Pr Error
in the display every time it is turned on if left off for more then a couple of seconds. There we go again...

Although many people do not feel too well with Spices, I would like to point out some of their characteristics that call my attention:

- they are the last LED-based series calculators from HP;

- the HP38E/C is the first of all programmables with a [P/R] toggle key (all prior units have PRGM/RUN switch keys)

- the HP38E/C and the HP34C are the first pocket calculators with registers/program shared memory (I am not sure if the HP95C also have it, but anyway, it is not a pocket calculator, right?)

- they were the only HP pocket calculators with solderless assembly (yep, I know it is the cause of many bad contact and faulty operation, but there is nothing easier to maintain...)

- they were cheap instead powerful (someone once mentioned that the postfixed 'E' was from Economics...)

Please, if there is anything wrong in the above list I apologize. I wrote it by heart, and chances are that some data miss accuracy.

Yep, I like them. No favorites, I only prefer the HP34C and the HP38C because they have continuous memory and offer more resources than the others.


Luiz (Brazil)

Edited: 17 June 2010, 1:18 a.m.


Interesting story...
I only have the 33E and 32E units. Without continuous memory, the 33E is, in my opinion, not a very practical programmable calculator. My favorite (until I get my paws on a 34C) is the 32E, which I purchased for an exam a couple of years ago that did not allow programmables. This is a well-designed and very useful general purpose scientific and statistical calculator with built-in hyperbolics and normal and inverse normal distribution functions. The keyboard layout is indicative of the ergonomics of the day. A far cry from the 50G (a 49g+ with different colours), with the poorly placed and sized ENTER key and division key that is smaller than the other three. What's up with that?

Although not as 'sturdy' as some of the other older models - Valentin Albillo's review of the 34C described it as "...rather flimsy, like you could crush it by merely closing your fist...", the Spice series calculators (34C in particular) were a great alternative for students to the more expensive contemporary models like the 41C.

Jeff Kearns


As I posted a few weeks ago after receiving and reviving my first Spice - a 34C - although I thought I was a Classic guy (with some Woodstock yearnings since my first HP was a 25) I really quite like these Spices. I did a full tear-down on the 34C and it's looking good and working really well. I do like the continuous memory, and the LEDs (of course) and the thousands separators! So I picked up a reasonable deal on a clean 38C, which arrived yesterday, and it's also a very nice little calc (it needs some clean-up around the battery/charger area but that's easy).

Couple of questions to the experts:

- The thin foam layer under the keyboard of the 34C is breaking up, does anyone have a good, readily available substitute for this ? the keyboard actions on both my Spices are really good, I don't want to mess this up.
- The battery cover on the 34C was all warped and won't stay in place, but the one on the 38C is tight and straight. The locking features look the same on both, is there a trick to these things?

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