Those of you who own/have used the Documation tabletop card readers know that they have a problem reading cards that have a diagonal cut on the upper right-hand corner. On many (but not all) of those cards, enough light spills over to the 12-row photocell that it thinks there is a punch in column 81, and the unit throws a READ CHECK. Carl Claunch has come up with a hack for the Control Card to work around the problem. I modified my M1000-L yesterday, and it now handles the problematic cards without error. As I mentioned on Facebook, "It ain't pretty, but it works." http://q7.neurotica.com/Oldtech/Documation/0809162259.jpg Al Kossow has made the modification documents available on Bitsavers: http://bitsavers.trailing-edge.com/pdf/documation/documation_fix/ I used Carl's daughterboard circuit, but replaced the 7433 quad-NOR (open-collector) and pullup resistor with a 7402 quad-NOR. I had initially tried Stan's simpler version, but didn't realize there was a trace underneath D8 connecting pins 2 and 13 and the mod didn't work. Mike Loewen mloewen@cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/