[unix-pc.general] PC7300/3B1 Monitor Questions

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