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HP-19C repaired
06-03-2017, 11:28 AM (This post was last modified: 06-03-2017 11:31 AM by PANAMATIK.)
Post: #20
RE: HP-19C repaired
HP-19C Display is running!

The HP-19C mainboard gave its first light!

Thanks Bob for encouraging my work.

This morning I started to work on the HP-19C processor board. My first surprise, when I measured the 21 pins of the 13-digit LED display, was that it is pin compatible to the 20-pin HP-25 Woodstock display, except for missing the rightmost digit. I could easily place one of my HP-25 LED modules directly into the HP-19C. And during test stage, I can easily do without the rightmost digit.


[Image: uc?export=view&id=0Bwx8KUfOUL_RUDdEYzI4SmJGVlU]

The first light!

What you see in the image above seems to be an upside down "HP-25E" Logo, but this is not possible electrically, and indeed it is not. I inserted an HP-25 ACT, which shows the normal Logo "HP-25E" on a Woodstock calculator. But the different HP-19C display driver displayes a small "d" instead of "P", which coincidentically is the letter "P" turned by 180 degrees. The letters "2" and "5" are symmetrical and identical when turned and only the letter "E" gives evidence that it is not an upside down text, but a reversed text. "E" would convert to "3" if turned. Thus the HP-19C display hardware simply is running in reverse direction compared to the HP-25.

It will be easy to change the newACT for displaying the digits in reverse order.

Next step will be to get any key press. This will prove, whether the PIK chip is still OK. Chance is given and better than I thought yesterday, because both display drivers chips are still OK and could be used already.

Bernhard

That's one small step for a man - one giant leap for mankind.
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Messages In This Thread
HP-19C repaired - PANAMATIK - 05-20-2017, 04:05 PM
RE: HP-19C repaired - Matt Agajanian - 05-20-2017, 09:09 PM
RE: HP-19C repaired - Paul Dale - 05-20-2017, 11:21 PM
RE: HP-19C repaired - Dr. Mabuse - 05-21-2017, 02:34 PM
RE: HP-19C repaired - PANAMATIK - 05-21-2017, 03:30 PM
RE: HP-19C repaired - AndiGer - 05-21-2017, 07:18 PM
RE: HP-19C repaired - Geoff Quickfall - 05-21-2017, 11:19 PM
RE: HP-19C repaired - PANAMATIK - 05-23-2017, 06:00 PM
RE: HP-19C repaired - Dr. Mabuse - 05-23-2017, 06:57 PM
RE: HP-19C repaired - PANAMATIK - 05-24-2017, 02:03 AM
RE: HP-19C repaired - Geoff Quickfall - 05-24-2017, 04:08 AM
RE: HP-19C repaired - PANAMATIK - 05-24-2017, 10:25 PM
RE: HP-19C repaired - PANAMATIK - 06-02-2017, 05:42 PM
RE: HP-19C repaired - BobVA - 06-02-2017, 06:04 PM
RE: HP-19C repaired - PANAMATIK - 06-02-2017, 06:42 PM
RE: HP-19C repaired - Dr. Mabuse - 06-02-2017, 06:17 PM
RE: HP-19C repaired - rprosperi - 06-02-2017, 08:25 PM
RE: HP-19C repaired - PANAMATIK - 06-02-2017, 09:07 PM
RE: HP-19C repaired - rprosperi - 06-03-2017, 12:25 AM
RE: HP-19C repaired - PANAMATIK - 06-03-2017 11:28 AM
RE: HP-19C repaired - david sanz - 06-07-2017, 12:05 PM



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