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DEC VRC-21WA CRT monitor -- service manual and/or schematic? *Not* at all urgent

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).
Reply to
Nicholas Bodley
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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
---^----^---------------------------------------------------------------
Reply to
Bob Larter

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.
Reply to
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:

--
Nicabod =+= Waltham, Mass.
Reply to
Nicholas Bodley

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