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At this moment there is on e-bay (5760806008) an HP55 offered as being a prototype. To me it looks like a regular HP55 were the backlabel, frontlabel and the label between the bottom rubber feet have been removed.

Do I miss something, or should I go for this one?



Based on the description of the auction, I have around 4 of these "prototypes" in my cupboard ;-)

In my language, I call them "degraded", "incomplete" or "calcs with missing parts".

But my command of english is not perfect...or maybe it's ebayish...

Oh well...

Best regards.


Could it be a replacement unit used by HP for servicing warranties ?

Quite correct. I could have several of these by removing the label, model number and pads.

Just no way to know if it is a prototype.

Pro: a non-standard sticker was on the back; could have been anything though

Con: a manual is included, all prototypes I am aware of do have a model label on the front case (even clear test shots have them), prototypes usually have engraved keys (this one doesn't, it uses standard two-shot moulded keys) and/or use a diffent case (grabbed from another calc, this one uses the standard case)

At 50 bucks, I would give it a try, but it's over 300 now <g>

Sounds like someone took a few stickers off and made it a prototype.

Pitty the auction does not claim the 55 has an image of a holy person ... it would have sold of many thousands to that casino in las vegas!


over 300 USD for a prototype HP-55?

How much for a HP-39/40 prototype?

How many are known to exist?


Edited: 21 Mar 2005, 5:51 p.m.

I have a prototype of the 48GX - is a 48SX with an eprom (standard off the shelf) cut out on the back. That's an easy one......

I have a pre intro demo unit of an 80 - empty shell no serial.

Finally service untis would have a heatstake serial number normally more rough than the manufactured one would have, they put the number on in the service centres.

The serial numbers on these machines was on a stick on label in the battery compartment. Easy to remove. Easy for HP service people to duplicate.