Televideo 912 terminal problems

Well, I was searching on Richard Shuford's wonderful website about video terminals, and I came across a bit of useful information. Apparently the power supplies and picture tubes are interchangeable between Televideo 910, 910+, 912, 912C, 920, 925 and 950 terminals. I had a 950 in the basement with a power supply problem, so I pulled the logic board out and stuck it in the 912, and connected the 950's external keyboard. It worked perfectly. This means there is something wrong with the 912 logic board. I closely inspected the 912 board, cleaned the dust off and reseated the socketed chips (the EPROM chip seemed to have some bent pins), but it didn't help. I noticed that the 912 board appears to have been modified. One or two things look like factory changes. The others look home hacked. Here are the changes that I can see: Those that look factory made: Green jumper wires on the bottom are connected between: Pin 1 and 4 of chip A77, an LS74 Pin 4 of chip A28, an LS74, and pin 8 of A44, an LS04 Pin 9 of A44, an LS04, and Pin and a solder point to the right of A51 Those that look home hacked: Cut traces on the top W8 Pin 11 of A77, an LS74 and Pin 3 of A28, an LS74 W28 W26 W6 seems to have a clumsy looking scrap of wire bridging it. W31, W32, W33, W34 look as if something was desoldered between all four The printer port seems to have been replaced or removed at time, judging from the brownish colored solder joints. The same goes for the S3 (printer baud rate) dip switch block. There are four white empty 18 pin DIP sockets on the right hand side of the board (RAM upgrade option?) There may be other modifications, but that was all I could find. Any ideas? Was this some upgrade, or was there supposed to be another module with this? Thanks! Ian Primus ian_primus(a)yahoo.com On Friday, October 25, 2002, at 06:29 PM, Sark wrote: