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Epic HP-9825 repair video series
05-17-2021, 11:18 AM
Post: #1
Epic HP-9825 repair video series
"CuriousMarc" is up to part eight (!) of a video series on repairing an HP9825 damaged by a power supply failure.

Besides the 9825 specifics, it's an excellent tutorial on troubleshooting TTL / DRAM-based systems, and there's lots of nice vintage HP test equipment to look at. (Made me a little nostalgic for the ThinkJet I parted ways with in my last move!)

He also posted an interesting companion video where he explains the (free) logic simulation program (LogiSim Evolution) he uses to model the 9825 memory refresh logic.



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05-19-2021, 11:53 PM
Post: #2
RE: Epic HP-9825 repair video series
Today, HackaDay did a blog on this video series.

https://hackaday.com/2021/05/19/repairin...nt-6350050

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05-20-2021, 05:42 PM
Post: #3
RE: Epic HP-9825 repair video series
(05-17-2021 11:18 AM)BobVA Wrote:  "CuriousMarc" is up to part eight (!) of a video series on repairing an HP9825 damaged by a power supply failure.

I followed every one. It is a must to watch!

Bernhard

That's one small step for a man - one giant leap for mankind.
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09-26-2021, 02:08 PM
Post: #4
RE: Epic HP-9825 repair video series
Marc finished his epic in Part 12(!), getting the keyboard / display working, but not before building a test jig for the HP dot-matrix LED displays.

This is my kind of series TV :-)
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09-27-2021, 01:35 AM
Post: #5
RE: Epic HP-9825 repair video series
Absolutely great series!
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09-27-2021, 01:41 PM
Post: #6
RE: Epic HP-9825 repair video series
(09-26-2021 02:08 PM)BobVA Wrote:  Marc finished his epic in Part 12(!), getting the keyboard / display working, but not before building a test jig for the HP dot-matrix LED displays.

This is my kind of series TV :-)

"Reality TV" at its best!
B^)

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