What were the "bare" CRTs pictured in so many early microcomputing photos?

[bzotto]

I frequently come across historic images of early microcomputer setups (Altair, Apple 1, etc etc) that indicate these systems were sometimes (often?) connected to what appear to be open-frame CRT displays sitting on desks. Can anyone shed light or offer links clarifying the nature of these displays? Were they some sort of wholesale monitors typically intended for industrial use or arcade cabinets? Why would they have been preferred over, eg, a small television or other encased display (like the popular Sanyos)? I can't imagine you could easily source these open high-voltage devices from a local Radio Shack, where did they come from? Would be very happy to hear from first-hand 1970s users, as well as anyone with non-speculative knowledge.

A few example images attached for clarification. Thanks!

 

[Chuck(G)]

Sure--sometimes called "OEM Kit" displays. Ball Brothers (they of the canning jars) was a big supplier, but there were many manufacturers. Bitsavers, for example, has information on the Zenith DT2 display. I still use one of those. Basically, add an enclosure and power supply and Bob's your uncle.

 

[NeXT]

Probably surplus tubes and chassis out of magazines and catalogs as well. If there is anything I can take from the beginning of the micro era it was that the hobbyist crowd were the masters of design jank and penny pinching. If they paid a dollar less for a TV because it was basically a tube laying on the table, that was a dollar that went towards their project.

 

[bzotto]

Sure--sometimes called "OEM Kit" displays. .... Basically, add an enclosure and power supply and Bob's your uncle.

Thanks Chuck. Where might you have purchased such a kit/set at that time? Was this solution (plus a power supply, anyway) less costly or otherwise more appealing than other solutions (buying/repurposing a small security type monitor or modding a little TV set)?

(And thanks for giving me a name for these)

 

[1944GPW]

Where might you have purchased such a kit/set at that time?

There were plenty of surplus dealers who advertised items like this in BYTE. You can find issues from #1 on archive.org as well as many other computing magazines.

 

[Chuck(G)]

I don't recall--I had quite a few of them. Probably a few from Haltek and the like. The Santa Clara valley was a beehive of hardware during the 1970s and 80s. You know, real manufacturing. If you couldn't source something for a prototype through the usual channels, there were always the surplus dealers, as well as friends at Walker's Wagon Wheel.

 

[bzotto]

the usual channels

Thanks again. Forgive me for the insistent followups, but what were the usual channels for you for something like this?

 

[Chuck(G)]

Oh, in addition to the manufacturer outside sales, Hamilton/Avnet, Arrow, Wylie come to mind. The mechanical people had their own sources, which I was not familiar with.

 

[mark0x01]

I purchased a kit like this from Phillips to go with my KTM2.

 

[bzotto]

Great, thanks Chuck (and others)-- appreciate the context here!

 

[Al Kossow]

CRT modules from Ball Brothers and Motorola Display Systems were widely used. The Ball ones are fairly distinctive because of the heavy
wire frame chassis they were built with. As Chuck mentioned, they were widely available through surplus channels or cannibalized
from old CRT terminals later in the 70s.

 

[jlang]

The open frame monitors were better than a modded TV in a couple of ways.
The video bandwidth was better than a TV.
They used separate horizontal and vertical drive (or sync) inputs.
They ran on DC power 12v or 24V. Safer no AC or hot chassis to deal with.
You could get a schematic.

 

[bzotto]

@Al Kossow and @jlang these are great additions. That certainly makes sense vs a modded TV set. Thanks.