Retrofitting Error board with pullup resistors and investigating additipnal circuits

 TWO OF ADDED SIGNALS ON THE BOARD CONNECTOR ARE NOT WIRED IN READER

I see that pins 9 and 13 of the Error card unique connector are not wired in the card reader, but they have connections on the board to some of the new circuitry and to VCC respectively. It is my opinion just based on this that the card was borrowed from a different model, perhaps with an option I don't have, but it has no effect since the reader isn't wired to those signals. 

ADDED PULLUP RESISTORS, VERIFIED OPERATION

I inserted the four 5.6K pullup resistors onto the board and now see the output signals correctly reflecting the state of the reader. I hooked up the interface and fitted it loosely into its home. The card cage on the Documation reader has six slots, but only cards 1, 2, 3 and 6 are fitted in my two models. The space where 4 and 5 would sit was wide enough to house the interface PCB and the cables and connections for the reader signal lines. 

READER IS AT LEAST PARTIALLY WORKING

The PC connected to the interface and was able to see the status signals such as Hopper Check (no cards in the input hopper). I then triggered the program to read cards and in fact it did go partway through the test deck I had inserted.

There is much that has to work properly for this to occur. The reader has to see the holes, not detect any errors, and it has to send impulses for each card column allowing the microcontroller to collect the entire card image. 

I haven't looked at the file that was produced yet - there may be good capture, nothing or mangled contents - but there is at least one problem occuring that has to be diagnosed and repaired. The interface microcontroller sends the machine status back after every command. This is a single ASCII character whose bits encode the various machine signals being tracked. 

The card reader signalled a pick check. This is a condition where the reader attempts to pick up and move a card sixteen times without success. The PC side program complained that along with the pick check, there is a status character Q. That may be an unexpected or invalid set of conditions - some research is needed.

By this time it was 4PM and I was ready to head back to the rental house for the evening. I didn't investigate the file that was read nor look into the Q status code. That is fodder for tomorrow's time in the shop.