1950's GE closed circuit monitor

[Olorin67]

Dug this out of my storage locker. I rescued this from MSOE when they tried to throw it out about 1989. Despite the appearance of the mask, this unit has a round CRT. I found 1957 date codes on some of the tubes, so that might be the date, even though that is late for a round tube. it has 4 UHF connectors on the back, with separate inputs for vertical and horizontal. Inside above the tube are two knobs labeled vertical and horizontal frequency. What kind of signal would this need to drive it?
I'll probably put this on my sell pile, i have too many other projects and need to unload some stuff.

[Dude111]

I understand about wanting to unload stuff...... It gets overwelming doesnt it??

[ChrisW6ATV]

Post a picture of the back panel with the jacks, when you can. Based on what looks like a burned-in dot in the middle of the CRT face, it might be something other than a standard video input monitor, more like an X-Y display. The CRT looks like a 10BP4, which might have been the only CRT available near that screen size in the late 1950s; even the "small" portable TV sets had 14-inch screens at that time, other than the 8-inch RCA.

Very interesting monitor, indeed.

[Olorin67]

I think it might be a 12" round tube with a mask making it about 10" diagonally . the dark spot it just dirt or crud between the tube and outer safety glass , the two surfaces almost touch at that point, trapping gunk. it has 4 uhf style jacks two are labeled vert and Horiz., not sure what the other two are for. my photo of those didn't turn out well.
Next time I go there I will try to get better pics and see what picture tube is in it.
the front panel reads GE Closed Circuit television. It came from an engineering school. this unit doesn't really have a big enough screen for classroom use, so it may have been used for something else. If it is from 1957, bigger monitors would have been available . i dont suspect it was for X-Y display, since it has vertical and horizontal frequency controls inside, so that must be a regular raster I presume.

[Olorin67]

i was able to clean up the photo a little, here's the back panel.

[dishdude]

Are those RCA jacks?

[Olorin67]

They are larger than RCA jacks, and have external threads., I think they are called UHF jacks? commonly used for antenna connections on CB gear. I have a couple late 60's Setchell Karlson school Tvs with similar jacks for composite video.

[bandersen]

They look like PL-259 jacks

[cameronflyer]

I agree with Bob, they look like pl259 jacks. You can get pl259 to RCA adapters if you want to keep the original in the monitor.

[earlyfilm]

Originally Posted by Olorin67

Despite the appearance of the mask, this unit has a round CRT. I found 1957 date codes on some of the tubes, so that might be the date, even though that is late for a round tube.

For B&W monitors where the operator sat close to the screen, the 10 inch size was common in the 1950s, with the 10SP4 being popular. It was aluminized and that helped protect the operator's eyes from CRT radiation. This tube is directly interchangeable with the 10BP4 with a minor tweak of voltages.

The 10BP4 and 10BP4A were not aluminized, but the "A" had a grey faceplate to reduce reflections. (I've never seen a "B" or its specs.)

The 10BP4C and 10BP4D were aluminized, one with clear glass and one tinted gray.

GE built the monitors for a reasonable price. For industrial use, they would have used a mass produced tube instead of a specialty one, to save a buck. It would not surprise me if you find the tube is "factory rebuilt."

James

[Electronic M]

I'd be interested in buying that set. PM me if interested.

[Telecruiser]

A PL-259 connector is also called a "UHF Connector." They are the same thing. Early professional video equipment used them on just about everything. In the late 1960s, BNC connectors began to take over, probably because they were smaller which allowed for more connectors on a smaller panel.

[Olorin67]

Tom C, your inbox is full...

[Electronic M]

Originally Posted by Olorin67

Tom C, your inbox is full...

Sorry, some PM conversation occurred after I posted here last. I made some space just now.

It is amazing.....Three weeks ago I cleared ~20 PMs to make some room and it is right back at max capacity earlier today.....And I thought the 90MB email MSOE had for most of my time there was obscenely tiny.

[kf4rca]

In the early days (50's) GE was #2 in the broadcast equipment field. They also made cameras and transmitters. Dumont was #3. One reason was the financing available at the time. RCA did their own financing. All you had to have was a license and they took care of the rest. The GE big ticket items (transmitters) were designed strangely. They were water cooled and RCA's were air cooled. The GE transmitters had red buttons for on air and green buttons for off air. Harris bought out the GE broadcast interests around '78 or so.