Unusual HP21 Modfication?
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03-30-2016, 07:06 PM
Post: #1
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Unusual HP21 Modfication?
I got to digging through my Woodstock scrap bin this weekend and, with some good advice from Bernhard, I brought two of the three of them back to life. In the process of doing so, I found an HP-21 with a diode added to the backside of the display driver section of the circuit board (photo attached) Anyone seen this before? And know what it's supposed to do?
There was also a paper sticker inside the back cover stamped "Jan 28 1976" with the pencil notation "K.B. + Logic" jotted on it, which seems to indicate it had been in for a repair at some point. |
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Messages In This Thread |
Unusual HP21 Modfication? - BobVA - 03-30-2016 07:06 PM
RE: Unusual HP21 Modfication? - PANAMATIK - 03-30-2016, 08:18 PM
RE: Unusual HP21 Modfication? - BobVA - 03-30-2016, 09:05 PM
RE: Unusual HP21 Modfication? - PANAMATIK - 03-30-2016, 10:27 PM
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