HP-70 erratic behaviour - first results

[Alberto Fenini]

Dear All,

this is the first follow up on the topic, i had some time and I have worked on the electronic side of the problem.

I had ordered and received the Deox and at first I have cleaned all the contacts, but the erratic behaviour was sitll there.


Then I have then realized than the HP45 and the HP70 are very very close from the chipset point of view, except for a couple of ICs.

Using one of my HP45 boards and one old shell I have transplanted from the HP70 board to the HP45 board the two different chips.



this is the original HP70 board





HP45 board ready to receive the ICs





transplat done !!





weird, but it works !!!!


I have now a working HP70 in the body of an HP45, although
the keyboard (keys) are those from the HP70.
It's kind of weird but it works !!

Now I'll work on the cosmetic side, I have already removed the scratches from the HP70 faceplate with the sandpaper, I'll later spray it with the Tamiya Flat TS80.

If the results will not be good enough, I will remove the
lettering from this faceplate (the one pictured) and I'll dissamble it from the black frame.

What do you think ??

Suggestions as always are very welcome,

take care Alberto