Almost a Red-Dot. It seems only to lack the hole!


I have got ah HP-35 from a american guy (SF, CA) and this seems to be a red-dot without the hole on the keyboard face plate. Ist serial number is 1143A4799 like you can see on the pictures. It have a battery pack with part code 03501A, the first type released by HP for this kind of calculator. Let me know how do you think about.
Thanks a lot in advance.

Edited: 4 Mar 2010, 10:16 a.m. after one or more responses were posted


It's an early Version 2. There are other differences between a Version 1 (Red Dot) and a Version 2. Early Version 2's shared a lot of similarities with the Red Dot, whereas later Version 2's were more similar to the Version 3, such as the serial numbers inside the battery compartment. Nonetheless, it's a nice find and looks to be in good condition.


Many thanks for your appreciated contribute. This calculator is in very good working order, after an accurate restore from a very dirty and oxidized state. It hasn't the original ROM bug. I have just ask to the seller the story of this calculator , but He hasn't answered yet. If he does I will inform you.



I guess it was a red Dot, but the upper faceplate was changed.
As I can see there is a red dot on the power slider as well as there is the typical serial number plate of the Red Dot.
Does it has a bug or not?


As you can read in my latest post, the calculator hasn't the ROM bugs, bu I agree with you about the possibility that the keyboard face plate could be not so old. I'm awaiting for some information by the seller.



It's a factory refurbished red dot.
The serial# sticker is without doubt a red dot (and not V2) sticker, the serial number itself matches this.
When the "bug" was discovered, some/most users sent their machine to HP to have the ROM replaced (you can probably see some soldering remains from the manual rework on the PCB). Often "bad parts", like a damaged case part, were replaced for free. The original red dot faceplate was probably worn and has been replaced by a V2 part (as if the red dot hole was good for anything anyway <g>), after fixing it, the back label had to be replaced as well - with a V2 part (stating the "35").


Maybe. Certainly the large rear label is not original and different from a Red Dot, but as you said would have been replaced if it had been refurbished by the factory. I am not so convinced by the serial number label, as there were a few Version 2's that had this style label (small numbers), and this serial number is higher than the earliest Version 2. Dr. Michael Eckstein has a database that has this information. You are correct that there is evidence of ROM replacement, and other evidence that the logic board itself is a Version 1 (Red Dot). Whether this was truly a Red Dot that has been factory refurbished or has been cobbled up from various pieces, some Red Dot and some not, is hard to tell, unless a factory work order or work makings can be found.


Thanks Michael, thanks Frank,
I have deleted the image of the battery pack and insert a new image of the gold contact, I hope this could help us to discover the mistery. I think that only the Red-Dot had this kind ofcontact bridge. Is true or not?
Frank, if you remember long time ago I purchased by you a RED-DOT s/n 1143A02874 and I are still the proud owner.



The V2 and red dot ser# label differ, so it's actually impossible to falsify a V2 into a red dot. Probably a handful of people do know what to look for, but it's better not to tell ;)
I don't think the "earlier V2 number" is the full truth, probably another factory refurbished machine - it's not too hard to imagine they had the ability to reprint a ser# label...


...that my '35, #1143A31237, purchased from the original owner, is an early version 2 with bug that was refurbished by the owner. The back label states "HP-35" and one can see faint remnants of the old label. Plus, the original owner provided documentation indicating when the calculator was serviced for the "bug."

I'm judging that it is early v. 2 (without opening it) based on lack of red dot and S/N label style. It is conceivable that the faceplate was replaced, but the original owner had the machine serviced within a year or so of purchase, so I doubt this.


Edited: 22 Feb 2010, 7:31 p.m.

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