myamin@cbnewsm.ATT.COM (m.yamin) (12/27/89)
I am seeking enlightenment (ha) about the PC7300 monitor. Mine works OK, but I'm paranoid. I called Randy at Video Display Corp. (1-800-241-5005) who bought Discovery Electronics' supply of 3B1 monitors, but he said they'd all been sold, to individuals, not to another vendor. So my first question is: Who has them, if I need one? The Service Manual lists two different monitor assemblies. These appear not to include the plastic, because "monitor bezel", "monitor bucket", and the 10/20 MB and 40/67 MB "top cover"s have separate part numbers. 7300 Monitor Assembly (12 volt) 403865330 3B1 Monitor Assembly (9 volt) 405076571 Are these plug compatible, which would imply that the "9 volt" is internally generated? If not, where does the "9 volt" come from? Neither power supply has it. The Reference Manual (thank you, Lenny Tropiano!) lists the following "JV" pin connections (presumably the video connector) on sheet 8 of 25: JV-1 VIDEO VSYNC JV-3 VIDEO HSYNC JV-5 VIDEO OUT (20 MHz pixel clock) JV-7,9 +12 volt JV-2,4,6,8,10 Digital ground A row of 720 pixels is output in 36 usec, followed by 8.8 usec horizontal retrace; there are 348 rows followed by 863.2 usec vertical retrace. This works out to a frame frequency a bit over 60 Hz. There is nothing to indicate that the video signals are any other than TTL logic levels. Does this mean that the commodity product called a "TTL monitor" is compatible with these signal levels and power supply, and could be used on the PC7300 with a little cable rewiring? Who made these monitor assemblies, and do they still? I can't believe that they were custom-designed for this box. M. Yamin my@m21ux.ATT.COM att!m21ux!my