new HP12C CPU...

[Bill Wiese]

Folks...

Awhile back the HP12C was redesigned (cheapened! - just look at the keys.) Apparently there were some hardware changes too - new CPU. (Or, maybe all this just means it went from a 2-chip to a one-chip design.)

Any idea of these hardware changes? Anyone have pix of innards of HP12C, new-vs.-old??

Regards,
Bill Wiese
San Jose, CA

[Vieira, Luiz C. (Brazil)]

Hi, Bill;

All voyagers (I'm not sure about the HP10C and the HP16C) had two HW design: an earlier one with a separate flex PCB (LCD plus IC's) and keyboard, and the other with an integral mainboard, all built on it. These voyagers worked with three LR44-type button batteries.

Later, when only the HP12C was available, it had its internals reduced to only one chip but kept the three batteries. Lately, the HP12C had its internals redesigned so it could work with only one 3-Volt cell.

I have one of each of the last two models and I had once posted a message with IC's numbers and ID's. I may have this text saved as a document, but I'll have to dig my hard disk a bit OR dig Forum archieves. No matter; as I have the calculators, I can also open them up and read the ID's again. I just want to know if you are interested on this data. Let me know.

Best regards.

[Raymond Del Tondo]

Hi,

maybe it could be interesting for the museum pages, too,
to be able to see photos of the old and the new 12C PCB for comparison.

Regards,

raymond

[Vieira, Luiz C. (Brazil)]

Hi, Raymond;

There are photos of the the old-fashioned Voyagers "guts", with a flex circuit assy, availabel in the Museum. Look here. The HP15C's structure differs only for an extra RAM PQPF (Plastic Quad Package Flat) chip. Others keep two chips only, and the later versions have one single PCB with all components. I have an opened HP11C and I can open the other two HP12C and scan them (I have no camera). I'll verify final image quality and, if they are fine, I'll offer them to Dave, let's see what he can do. In the meantime, I'll send it to those who are interested on seeing these inner Voyagers.

Cheers.

[Raymond Del Tondo]

Hi Luiz,

thanks for your response.

Actually I have opened some of my 11C's and 15C's a while ago, and they've all the same single pcb layout.
That was helpful then because I could replace the display easily.

What I would be interested in is the new redesigned layout of the 3 volts 12C;-)

Cheers,

Raymond

[Vieira, Luiz C. (Brazil)]

Hi, Raymond;

I'll scan both the 3-volts, 1 cell HP12C "guts" and the other, a bit earlier 4.5-volts, 3 button batteries, so you can compare them. Both of them have only one do-everything chip and one of them (I'm not sure which of them) uses an Agilent chip.

I just cannot do it right now, but I'll scan and send the images today. If there is someone else interested on these images, please, let me know so I'll send only one e-mail to many addresses.

Best regards.

[Gordon Dyer]

Hi Luiz, I would be interested an the scans of the PCBs.

Thanks

Gordon

[Vieira, Luiz C. (Brazil)]

Hi, Gordon;

They're going to you right now.

Best regards.

[Harry (Germany)]

No text

[Vieira, Luiz C. (Brazil)]

Hi;

hope you enjoy.

Best regards.

[Y K Wong]

Hi Vieira,

Did the last batch of 12C change to 3V single battery? Can I have some pictures too :-)

[Vieira, Luiz C. (Brazil)]

Hi;

the zipped file with the pictures is uploading right now.

Cheers.

[Y K Wong]

Hi Vieira,

Thank you so much for the pictures...The reason I ask was because I have a few 12C and they were all manufactured in either U.S. or Singapore and I do not own one that made in China. Recently, I have acquired a 12C with really cheap looking printed "keys", one 3v CR2032 battery (similar to your images of those made in China), however, there is no back label and totally without serial number! Since the calc is currently at home, I might open it up tonight to compare against your pictures. By the way, I got this calc from the same gentlemen that sold me the X25 and Xpander and he used to work closly with ACO!

Cheers