|Re: HP97 restore project|
Message #2 Posted by Vieira, Luiz C. (Brazil) on 5 Dec 2009, 8:29 p.m.,
in response to message #1 by Alberto Fenini
I do not have much experience with Topcats, but I have an HP97 and it had a nonworking card reader(/writer). The rest of it works fine, so I never had to deal with its internals. About the card reader, I had to adjust the many contact lids (three, IIRC), and it is not that hard.
Again, be careful when using the charger. The HP97 has a different power circuit when compared to the HP67. In the HP67, the charger has three wires (unregulated Vcc, regulated Vcc and common), but the HP97 uses a two-wire AC adapter. So, it depends on batteries installed to work safely. In the 80's, I once had my first HP82143A (HP41 peripheral printer) damaged just for plugging the AC adapter and turning it ON without batteries. I did not have to wait for a 'twice in a lifetime' to remember it for good!
The behavior you describe actually leads to a bad ACT (main processor), but as you have a good experience with the HP25, go ahead. And keep in mind that the Woodstocks and Topcats share the same ACT processor (except for the HP27, which uses V-MOS technology). In most cases a 'transplantation' is feasible.