Friday, December 17, 2010

Attendees: George Ahearn, Stan Paddock

With open questions, George Ahearn and Stan paddock decided to go into the CHM and try to answer the pending questions.

Questions we had were:

1.     What happens if the temperature sensing card reports the correct temperature?

2.     What happens if we run the cards starting with the 80 punches first instead of last?

3.     What happens when the punches go from right instead of left to right?

When we entered the room it was very cold. Way below 70 degrees F.
We ran the PTEST program and go the same results as before.
We turned the cards around for case 2 and 3 and got errors until the number of columns went bellow the thresholds as before.

We pulled the temperature card and soldered all sensors closed.  This told the machine that the temperature was less than 70 degrees F.
We ran PTEST again and got just about the same results as before.
We pulled the card (indicating that the temperature was over 95 degrees F  and got significantly more errors. 


Following the ALDs for the temperature sensors, they control a bias to the memory current controller circuit.
While the temperature sensors are broken, they are not responsible for the errors we are seeing. However, the change in the errors with the cold and hot said we are on the right track.
Next week we will inspect the current control circuit and see if we can find the problem there.


We have found some small devices online that will open and close as the ones in the IBM 1401 are suppose to do. We will being buying a batch of these and update the cards we have in both machines so they work properly. 


While we had not used up the time Ann Ahearn had allocated to us, we decided to see if see could start trying to find out what was wrong with the German machine. Much to our surprise, it seemed to work fine.


We ran the PTEST program on the German machine with no reported errors.


Bill Flora said that he could not get the 'ripple read' program to run on the Connecticut machine.


We tried it on the German machine and got the same results.
We ran the cards through the PTEST program and 5 cards were reported with errors.


Next week, we will use the IBM 513 to produce a new card deck for the test.