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Unusual HP-21 ?
11-11-2017, 09:08 PM
Post: #1
Unusual HP-21 ?
Hi,

I've just received my first red LED's HP! Smile
But unfortunately, it exhibits the problem described in this thread: http://www.hpmuseum.org/forum/thread-264...ight=hp-21

I took a look at the internals and it seems the PCB is not the same as usual.
It has got an AMD 1820-1983 (power-on reset, battery low comparator) and a dedicated power supply converter.

Did someone already encounter this version?

I have to check if there is some noise on the power supply, and if unsuccessful it will become a host for Panamatik's Woodstock low power module!

[Image: uc?id=1SARaQlp9x5MWQ30haXefEpvvXuHJEzRl]

s/n: 1710S23250

Jean-Christophe.
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Messages In This Thread
Unusual HP-21 ? - jch - 11-11-2017 09:08 PM
RE: Unusual HP-21 ? - jch - 11-25-2017, 10:16 PM
RE: Unusual HP-21 ? - jebem - 11-25-2017, 11:00 PM
RE: Unusual HP-21 ? - jch - 11-26-2017, 08:12 PM
RE: Unusual HP-21 ? - jebem - 11-27-2017, 10:34 AM
RE: Unusual HP-21 ? - PANAMATIK - 11-26-2017, 07:44 AM
RE: Unusual HP-21 ? - jch - 11-26-2017, 08:51 PM
RE: Unusual HP-21 ? - jch - 03-06-2018, 12:31 PM



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