HP-65 goes on hold after reading a card

[teenix]

(11-17-2020 10:21 AM)albertofenini Wrote:  if the same logic boards works well with another card reader this excludes the CRC inside the Hybrid and leave as faulty the Sense amplifier ?

We tried last night but when the card reader is totally disconnected the motor will not run and the card will not move, we'll try to disconnect everything but the motor

I would think so, or the sense PCB and or connectors.

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Yes that would be the case because the sense PCB is missing, but if you eased a non write protected card in just enough, the switches would operate and the CRC would think a card is going though and you should be able to capture the WA WB data on your scope.

Note that I haven't tried this, but as there is no feedback to the CRC except the switches it should work.

You will get an Error on display because the CRC wont see the card exit in time and think it is jammed.

Another thing you could do, is to remove the WA and WB pins on the card reader PCB so they are open circuit to the sense chip when the sense board is connected to the CPU. Then see if the WB signal improves.


cheers

Tony