Very early HP25

[Harald]

I have just received an HP25 today. The seller had broken it by plugging it in and turning it on with the original battery pack which of course is dead. Luckily nobody had tried to pry out the battery pack that was stuck due to leaking batteries.
To my surprise it looks brand new and seems to have seen hardly any use. Also it is a very early one, serial number is 1510A31263. Does anyone have an even earlier one?
The ACT is probably fried and there is quite a bit of corrosion on the main PCB. The keyboard had very little corrosion though and cleaned up nicely. For now I have replaced the main PCB with one from another calculator, and now the 25 is alive again!
The decimal dots are little triangles rather than rectangles. Is that typical for the early woodstocks? I also have a 21 with such a display.

I'll try and post pictures later.

[Massimo Gnerucci]

(07-24-2015 10:06 PM)Harald Wrote:  Also it is a very early one, serial number is 1510A31263. Does anyone have an even earlier one?

1509A044xx

[BobVA]

1508A01xxx

Bob

[Harald]

And do yours also have the triangular decimal dots?

[Massimo Gnerucci]

(07-25-2015 09:51 AM)Harald Wrote:  And do yours also have the triangular decimal dots?

I'll have to dig in the pile... :)

[jebem]

(07-25-2015 09:51 AM)Harald Wrote:  And do yours also have the triangular decimal dots?

Yes, my HP-25 s/n: 1508A10390 does.

Concerning the battery pack, I decided to have a go and have carefully opened it, clean all the electrolyte mess from the original batteries, and have installed two new unbranded Chinese Ni-Cd AA 900mAh 1.2V elements.
So far it holds a full charge for months (literally) when not in use.

[BobVA]

(07-25-2015 09:51 AM)Harald Wrote:  And do yours also have the triangular decimal dots?

Yes.

[Etienne Victoria]

From the Museum (Collector's corner)

Quote:Comma and Dot Variations

Some HP calculators made for the European market had the commas and dots reversed as compared to their American counterparts. The 20 series used two different displays with the decimals being either square or triangular. The triangular decimals could be interpreted as either dots or commas and so were sold in both the US and Europe. The 30 series models had a jumper change between European and U.S. comma/point formats. (Many later models can be switched by the user.)

[Harald]

(09-09-2015 07:01 PM)Etienne Victoria Wrote:  From the Museum (Collector's corner)

Quote:Comma and Dot Variations

Some HP calculators made for the European market had the commas and dots reversed as compared to their American counterparts. The 20 series used two different displays with the decimals being either square or triangular. The triangular decimals could be interpreted as either dots or commas and so were sold in both the US and Europe. The 30 series models had a jumper change between European and U.S. comma/point formats. (Many later models can be switched by the user.)

I wasn't aware of Woodstocks with commas. Have you ever seen one?
But I did know the 30 series have the jumpers.

[PANAMATIK]

(09-09-2015 07:59 PM)Harald Wrote:  I wasn't aware of Woodstocks with commas. Have you ever seen one?

There are no Woodstocks with additional commas. The display driver chips do only support one decimal point for each digit. Depending on the display it is either a square or triangle.

My 1510S41417 has triangle dots.

Added: I forgot to tell, hat I am a real fan of the triangles

Bernhard

[PANAMATIK]

(07-25-2015 03:14 PM)jebem Wrote:  Concerning the battery pack, I decided to have a go and have carefully opened it, clean all the electrolyte mess from the original batteries, and have installed two new unbranded Chinese Ni-Cd AA 900mAh 1.2V elements.

If I may recommend the following:

It is not necessary to open the battery pack completely to replace the batteries. Just cut the 5 mm bridge between the two batteries at one side and you can remove and replace the batteries.

Bernhard

[Brad Barton]

My 1510A27237 has the triangular dots. I learned from Geoff the this is consistent with the 5-05 code on the back of the small LED display board.

Brad

[Geoff Quickfall]

Check out the following URL. It is a PDF PowerPoint presentation for HHC2015 this past weekend. There are slides that say video in the upper right hand corner. Of course these will not be video in the PDF version.

Scroll down to slide 11 (numbered slides) and you will see the comma versus point Brad was referring to.

http://panamatik.de/HHC2015Presentation.pdf
Harold:

How did you get the case so white? I have tried bleach, peroxide and sunlight but cannot get that new white look back.

Cheers, Geoff

[Harald]

(09-30-2015 08:06 PM)Geoff Quickfall Wrote:  Check out the following URL. It is a PDF PowerPoint presentation for HHC2015 this past weekend. There are slides that say video in the upper right hand corner. Of course these will not be video in the PDF version.

Scroll down to slide 11 (numbered slides) and you will see the comma versus point Brad was referring to.

Harold:

How did you get the case so white? I have tried bleach, peroxide and sunlight but cannot get that new white look back.

Cheers, Geoff

Following URL? Hmm, all I saw was the link on Bernhards website, is that the presentation you were referring to?

I think the case looks a little whiter in the pictures than it actually is. But it is not too bad compared with a few others I have. Especially my 97 has become quite dark.
However I can't recommend anything, as this is how I bought the calculator - I didn't do any cleaning.

Cheers,
Harald

Edit:
Ohh, I think you weren't even talking about my calculator, but the one jebem posted a picture of. Maybe he knows a good way to bleach the case.

[jebem]

(09-30-2015 10:04 PM)Harald Wrote:  Ohh, I think you weren't even talking about my calculator, but the one jebem posted a picture of. Maybe he knows a good way to bleach the case.

Well, I believe it is a combination of two factors:
-I use to dismantle my new acquisitions piece by piece as much as possible, then I use warm water and regular detergent for hand dishwashing to rub the case parts gently with a sponge.
- And a small trick of a red background, causing the white/yellows to be whiter when I use this low cost Samsung ST60 digital camera

[brickviking]

(10-02-2015 07:16 PM)jebem Wrote:  - And a small trick of a red background, causing the white/yellows to be whiter when I use this low cost Samsung ST60 digital camera

Ahh. Doesn't it have a White Balance setting? I'm rather grateful my Fuji F5600 does, it makes stuff look much better under indoor lighting.

(Post 34)

[Geoff Quickfall]

Added missing URL on post 13.