HP-65 more on the card reader

[albertofenini]

Hi everyone,
last nigh we spoke with an old friend from the Forum, Ignazio, which added his contribute to all of yours,
and I'd like to thanks everyone and Ignazio for this precious support.
We did some tests on one of the four units, will do more tests on the other over the weekend.

This is a early unit, S/N 1333A20583 where we reinforced the worm gear and used o-rings.
The motor switch works, we tested it, but we kind of knew this since the card was pulled thru.

Tests have been done without the logic board, measuring the switches behavior at the bottom pins.
These tests were done with PRGM switch in PRGM position.
I can confirm that all of the units, including this, go in programming mode,
and we have been able to key in programs and let them run.

We used two multi meters and we observed that :
in the case of a Standard Pac card (corner clipped) HDS closes first, then WPS closes.
in the case of a recordable card (cirner unclipped) WPS closes first, then HDS closes.

Then, when the card is pulled a bit more inside, both switches close.

Nevertheless the unit is not writing
Even when it reads, the program is not working, trying to run it put the machine in endless loops.
Note : we have not checked the listing in the machine read from the card with the original listing, we'll do it very soon

However, only with this unit, something weird happens.
After the card has gone thru (in the picture in read mode, but it happens also in recording mode) the display shows a strange 000 with some missing segments.
Extracting the card from the unit will take the display back to a steady 0.00

I totally agree with Tony, it's unlikely that all of the four controllers are not working, as is unlikely that all of the head, or all of the motors are not working properly.

Tony suggested to use the oscilloscope to see the activity on WA and WB, we have not done it, we will do it soon.
It would be very helpful to know what kind of activity we should expect

If in the meantime anyone has a suggestion will be more than happy to follow it
Thanks everyone for the continuous support !

   
No card

   
Standard Pac card

   
Recordable card

   
Display problem

   
Backplate & Switches