curiousmarc
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Lots of HP Nanoprocessors and TI Clock Chips
🕑 Added 2020-10-04 02:52:38 +0000 UTCMy previous video on TI clock chips was a (rewarding) detour on the road to repair my HP 98035 clock modules. Thanks to the contributions of former HP 9825 developer Steve Leibson http://www.hp9825.com/ Patron Jack Rubin, collector Bob Rosenbloom https://youtu.be/2OkTm0vI7As and vintage HP warehouse extraordinaire Ed Blacksmith https://youtu.be/qn2Zz8X41dI I have now acquired no less than 6 HP 98035 clock modules. And zero of them work. Zilch, nada, nothing. Even after changing the batteries and a few clock chips.
Well, not anymore! Thanks to my TI chip breadboard LED watch and the recent Nanoprocessor reverse engineering by Ken Shirriff with the help of Antoine Bercovicci http://www.righto.com/2020/09/hp-nanoprocessor-part-ii-reverse.html I have now gained a much better understanding of the two boards in this module. Enough to repair 6 cards to make 3 modules (see story in the pictures and legends).
Damage so far: 4 bad clock chips, two bad CD4069UB hex inverters, one bad 1 MHz crystal, one bad 32.768 kHz crystal, a connector with a hidden broken pin and a bad PCB. My most hacked repair was the board with internal wires eaten by the battery leakage, which necessitated a whole bunch of bodge wires to finally bring it back to life.
And I even found what our mysterious 3rd button does on the watch chip, by looking at the disassembled Nanoprocessor ROM code: it's a clock hold button, only works in conjunction with pressing and holding the read button to display the seconds. It will stop the seconds from advancing.
3 working modules is more than I need, but should I unleash the big test HP weaponry and coerce the rest of the boards into submission through logic analysis? What do you think?
Comments
CuriousMarc
Evil temptation...
Joel
I vote coercing the others into submission! These deep dive repair videos dig up so many fantastic details and fun facts along the way... they never get old. You could set out to repair 30 more of these and I would eagerly watch every minute of it :)
I have been following this eagerly. Looking forward to the video! In these crazy times your videos are my safe space :-)
