Why are these ancient "Conrac" CRT monitors so expensive?

A lot of the hits for "Conrac" mention them being used in medical diagnostic equipment. In those applications, the displayed brightness needs to be linear, accurate, and reproducible because the difference between "you're fine" and "you've got cancer" can be a slight difference in ultrasound return signal level.

I saw these in 70s espionage flick "Three Days of the Condor". Why are they so expensive? What use do they have in 2023?

For another $1k, you can get an LCD conversion kit [0]! It looks like this manufacture created displays for industrial uses. I suspect they're high-quality monochrome displays, if that is the case. I found one reference that indicated 800 lines [1] at center with BNC input (woah!) [8] - the listing says model 2620 but the body text indicates 2640.

This isn't the same monitor, I don't think, but interesting none-the-less [2]. This page talks about how these displays were the top of the pack [3].

It looks like Conrac is now DATA MODUL [4] and they still make industrial displays today [5]. Looks like these monitors may have gone for $4-$7K [6]. You can look at other sources by searching for NSN 5820-01-458-2427, but I couldn't find anything more detailed -- this clearly has military uses in the US and NATO.

If you want, I'd suggest picking up the manual from eBay [7].

[0] https://monitech.com/products/lcd-upgrade-kit-for-9-conrac-2...

[1] https://www.soundbroker.com/video/listingview/conrac-2620c9-...

[2] https://worldphaco.com/uploads/The_1987_Vintage_Avionics_Con...

[3] https://www.tvtechnology.com/equipment/display-technology

[4] https://www.naval-technology.com/contractors/materials/data-...

[5] https://www.data-modul.com/en/products/data-modul-products/d...

[6] https://nationalstocknumber.info/national-stock-number/5820-...

[7] https://www.ebay.com/itm/144035355910

[8] Copy and paste:

> THE MODEL 2640 PROVIDES A CRISP, STABLE AND DISTORTION FREE DISPLAY FOR CRITICAL EVALUATION OF IMAGES GENERATED BY MEDICAL DIAGNOSTIC EQUIPMENT AND OTHER DEMANDING APPLICATIONS SUCH AS SURVEILLANCE AND FLIR IMAGING. FEATURES INCLUDE METAL CABINET, SELECTABLE INVERSE VIDEO AND EXTENSIVE OPTIONS INCLUDING: LINE RATE, CRT PHOSPHOR, ASPECT RATIO, INPUT POWER AND RUGGEDIZATION.

> SPECIFICATIONS :

> CRT / STANDARD FORMAT 9" DIAGONAL CRT / 4:3 ASPECT RATIO OVERSCAN STANDARD PHOSPHOR P45 (WHITE), POLISHED RESOLUTION > 800 TV LINES @ 525/60 SCAN RATE (15.75 KHZ) BANDWIDTH 30 MHZ FREQUENCY (FIXED) - STANDARD HORIZONTAL - 15.75 KHZ (525/60) POWER - STANDARD 115 VAC 50/60 HZ ｱ 10% POWER CONSUMPTION 40 W NOMINAL USER CONTROLS / ADJUSTMENTS FRONT: BRIGHTNESS, CONTRAST, INVERSE VIDEO, H. HOLD, V. HOLD, HEIGHT, WHITE LEVEL (INVERT MODE), POWER REAR: INT/EXT SYNC, HI / 75� TERMINATION, FOCUS

> SIGNAL CHARACTERISTICS COMPOSITE VIDEO: 0.50 TO 2.0VPP, 1.0V NOMINAL

> NON-COMPOSITE: 0.35 TO 1.7VPP, 0.7V NOMINAL

> EXTERNAL SYNC: 1.0 TO 8.0VPP, 4.0V NOMINAL

> VIDEO INPUT BNC LOOP-THROUGH VIDEO AND SYNC, VTR DIMENSIONS 9"H X 8.7"W X 10.7"D WEIGHT < 12 LBS (5.5 KG) SHIPPING WEIGHT 14 LBS (6.4 KG) TEMPERATURE 0ï½° TO 50ï½°C, OPERATING -20ï½° TO 70ï½°C, NON-OPERATING HUMIDITY 10% TO 90% RH, NON-CONDENSING ALTITUDE 10,000 FT (3,000 M), OPERATING WARRANTY 1 YEAR PARTS AND LABOR OPTIONS ASPECT RATIO: 1:1, 4:3 UNDERSCAN

> LINE RATE: 625/50, 675/60 TO 1167/60 INPUT POWER: 230 VAC, 12VDC, 18-36 VDC, 400HZ CRT PHOSPHOR: P4, P31, P39 RUGGEDIZATION ACCESSORIES 19-INCH RACK (2R, RC, RBR, RBL, RXR)

Hopefully I've cited my sources well enough that @hbomberguy will leave approve.

Antique value.