17 Apr
2005
17 Apr
'05
9:09 a.m.
On Sunday 17 April 2005 08:06, David Comley wrote:
- I'd like to use a surplus VT420 as the display
for
the DEC 350 Pro I picked up. This will entail
identifing a point on the VT420 schematic where I can
inject the composite video signal from the 350. So I
need the VT420 schematic. Does anyone on the list have
one ?
First off, before you go around modifying VT420s, you may want to test
the Pro first. The 'composite' output of the machine nicely matches
NTSC (RS-170) composite signal specs, so you can hook the output
directly to a TV with a composite input. Beware that the TV will
overscan the signal a bit, but you should see *something* when you
first power up the Pro to indicate that it's at least somewhat
functional.
As far as the VT420 schematics, I don't have any, but you might try
finding a VT220 to use, or a professional NTSC video monitor. I've got
a few of each and would probably try those first... the VT220 isn't too
different from the VR201 that should go with the Pro, and is probably
easier to modify (it even has the composite video output on its back,
so you might be able to trace what to do without schematics event).
Pat
--
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