HP9810A alive again!

[Mattis Lind]

After replacing a lot of dead National Semiconductor TTL ICs this nice
little machine from 1972-1973 is running again. It works perfectly to do
calculations and also to create programs. I also managed to both store and
restore a program written onto a home made magnetic card. Home made since I
wasn't able to find any.
There are a few issues left: The belt in the card reader is slipping a bit
so a replacement would probably be needed to get it working 100%. One
segment in the display is dead.

Anyway: Here is the writeup of the restoration:
http://www.datormuseum.se/computers/hewlett-packard/hp9810a

and here is a video-clip: https://www.youtube.com/watch?v=C9rBoWvze48

Enjoy!

/Mattis