prindle@NADC.ARPA@sri-unix.UUCP (09/17/84)
You can make an excellent B&W monitor out of one of those cheap ($75) 12" TVs (I did it with a Panasonic). An isolation transformer is a must - you can make one out of two Radio Shack 24 volt transformers (the big ones, about $6.89 each) tied back to back. By tapping in one transistor away from the picture tube cathode, adding bias and level controls, and feeding in the (truly hefty) luminance signal from a Commodore 64, I got a high quality, high contrast (adjustable) monochrome display far better than most monitors I've seen on display for more bucks. The secret of this cheap mod to the set (4 wires: GND, +10V, Luminance in, and Luminance out <for restoring TV mode>), is that the Sync and Audio still take the RF modulator path!! Sure, the screen shifts about 1/4 inch to the left (the sync is slightly delayed), but the display is great. I suppose you could make a similar mod to a color TV to feed raw luminance and chroma in, but you'd need a lot bigger isolation transformer, and more complex surgery; too much for me, I just bought a 1702. P.S. It seems a whole new industry has been spawned from personal computing. I have seen no less than 3 companies now advertising TV receivers without display (sort of like a VCR sans CR) to put the Hill Street Blues right there on your computer monitor!
dmt@hocsl.UUCP (09/21/84)
I have created quite a few B&W monitors by surgery on an
old TV set. (I have yet to try a color monitor.)
The results were mixed. Most worked adequately, though
resolution hardly compared to a decent monitor.
They were also troubled by:
- Some wavering and wobbling, seemingly tied to 60 Hz.
- Serious pulling and tearing at boundaries between
regular and inverse video lines. (Really anyplace
that went from mostly black to mostly white for
a dozen or more lines.
I have had much better experience getting old monitors and
revamping them. There are a surprising number on the market
through surplus houses. For instance, I just opened a mail-
order surplus catalog with monitors for $23.33, $28.88, $29.88,
$39, and $69. Many are good Motorola chassis. The catalog is
from BNF Enterprises in Peabody, MA (617-531-5774).
I've fixed up a couple from this genre, with excellent results.
(Only one of those was from BNF.)
Consider this path the next time you want an inexpensive monitor.
Dave Tutelman