DEC VRC-21WA CRT monitor -- service manual and/or schematic?

[Nicholas Bodley]

This is close to the mother of all computer-related curb finds; I'm
basically blessed. I even have the [VGA] to five-BNC "breakout" cable for
it. When I got it, it was in nearly-perfect condition, and has some minor
problems I can live with. Color purity has actually improved with time.

I'd love to know more about it (particularly the scan frequency ranges),
and am curious whether "WA" means "wide angle". It seems close to a
Mitsubishi DiamondPro 21TX (TRN9105SKTK), which has scan ranges of [H] 30
to 93 kHz, [V] 50 to 152 Hz. Res. is 1600 x 1200 max.

It must have a Mitsubishi Diamondtron CRT, most likely built under
license from Sony; interesting that its faceplate is spherical (or close)
rather than essentially toroidal (as in Trinitrons). Somebody was able to
design a spherical aperture grille (has two nearly-invisible
stabilizing"wires").

The geometry corrections for the left and right edges don't seem to need
to be so elaborate; fun to have...

It weighs about 85 lb, and seems to dissipate about 250 W -- that makes
it a mild room heater in winter, and mandates a cooling fan aimed at the
rear in summer. (I don't have a/c).

Of course, flat panels are the way to go; I know that, although its
colorimetry might still be better, along with better resolution
flexibility.

Any info. about the serial port (no kidding) on the back (a DIN
connector)?

Also curious whether there's any likelihood of using it as a direct
monitor (i.e., no computer) for a digital TV receiver; I rather doubt
that. BNC's are R, G, B video and H and V drive. Seems that direct video
these days is Y and (?) Cb Cr, which could be converted to inputs for
this, but I'm a retired tech. and not prepared to build a video
converter; I don't expect an affordable one to be on the market.

Even access to a spec. sheet would be welcome. Basically, I'd simply like
to know more about it. (I don't even know, in any detail, how wide-
frequency-range scan circuits work; they must be enhancements of TV
receivers circuits, of course.)

As we say, thanks in advance!

Best regards,
--
Nicabod =+= Waltham, Mass.
Have Sony KV-1311 with remote,
still working -- monitor/TV for
early Amiga 1000 system (still have).

 

[Bob Larter]

Nicholas Bodley wrote:

Of course, flat panels are the way to go; I know that, although its
colorimetry might still be better,

Most probably true. LCDs are deficient for photographic work, as they
produce poor shadow tones & are hard to calibrate.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Nicholas Bodley]

On Wed, 15 Jul 2009 19:58:11 +1000, Bob Larter wrote:

Nicholas Bodley wrote:
Of course, flat panels are the way to go; I know that, although its
colorimetry might still be better,

Most probably true. LCDs are deficient for photographic work, as they
produce poor shadow tones & are hard to calibrate.

Bob, thank you for confirming what I suspected. Considering the way LCD
"light valves" work, what you say is not surprising. Unless I'm horribly
mistaken, every row and every column in an LCD panel has its own
waveform, and even with modern electronics, I have doubts about whether
the brightness of every sub-pixel (one primary color) is close to ideal.

Btw, still hoping for more info, but I'm patient.

will probably get a flat panel at the MIT Flea Market tomorrow to use on
days too hot for my DEC CRT.

Last summer, I held my face above the hot-air grille on the back, and if
it smelled bad, I rigged up a fan promptly. I even contemplated making a
hood with fans to place over the back...

My best to all,

--
Nicabod =+= Waltham, Mass.

 

[Nicholas Bodley]

Update: Googling on simply
DEC VRC-21
gives many more hits. One fellow has a nice PDF available for an earlier
VRC-21, iirc the VRC-21H series. It did not yet have the on-screen config/
adj menu, only a miserable set of 5 or 6 LEDs that gave a code to signify
which function you were adjusting or selecting. However, the basic
monitor might well be similar. HTH!

Fwiw, haven't learned anything more.

History:

On Tue, 14 Jul 2009 17:51:35 -0500, Nicholas Bodley wrote:

This is close to the mother of all computer-related curb finds; I'm
basically blessed. I even have the [VGA] to five-BNC "breakout" cable
for it. When I got it, it was in nearly-perfect condition, and has some
minor problems I can live with. Color purity has actually improved with
time.

I'd love to know more about it (particularly the scan frequency ranges),
and am curious whether "WA" means "wide angle". It seems close to a
Mitsubishi DiamondPro 21TX (TRN9105SKTK), which has scan ranges of [H]
30 to 93 kHz, [V] 50 to 152 Hz. Res. is 1600 x 1200 max.

It must have a Mitsubishi Diamondtron CRT, most likely built under
license from Sony; interesting that its faceplate is spherical (or
close) rather than essentially toroidal (as in Trinitrons). Somebody was
able to design a spherical aperture grille (has two nearly-invisible
stabilizing"wires").

The geometry corrections for the left and right edges don't seem to need
to be so elaborate; fun to have...

It weighs about 85 lb, and seems to dissipate about 250 W -- that makes
it a mild room heater in winter, and mandates a cooling fan aimed at the
rear in summer. (I don't have a/c).

Of course, flat panels are the way to go; I know that, although its
colorimetry might still be better, along with better resolution
flexibility.

Any info. about the serial port (no kidding) on the back (a DIN
connector)?

Also curious whether there's any likelihood of using it as a direct
monitor (i.e., no computer) for a digital TV receiver; I rather doubt
that. BNC's are R, G, B video and H and V drive. Seems that direct video
these days is Y and (?) Cb Cr, which could be converted to inputs for
this, but I'm a retired tech. and not prepared to build a video
converter; I don't expect an affordable one to be on the market.

Even access to a spec. sheet would be welcome. Basically, I'd simply
like to know more about it. (I don't even know, in any detail, how wide-
frequency-range scan circuits work; they must be enhancements of TV
receivers circuits, of course.)

As we say, thanks in advance!

Best regards,

--
Nicabod =+= Waltham, Mass.