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Help with an old monitor

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leonphelps

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May 9, 2011
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Hello,

Helping a friend trying to figure out what type of monitor he has. Basically the thing has been running non-stop at his work for about 1984. It has 8 pins for the video. There is a main board type of PC connected to it. Burn in is pretty bad, so not really thinking of repairing.

I am assuming the monitor is the problem since its age. Main board looked to be a 286 or 386.

I am thinking I need to figure out what type of monitor it is including the video specs then see if I can somehow convert it to VGA so I could use a regular LCD.

There are adjustments marked vol, bright, focus, screen, v-lin, v-height, v-hold and h-hold.

thanks again in advance.




Any guidance would be greatly appreciated. People at my local TV shop were pretty much no help at all.

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Looks like a Hirose S1308 connector. You used to see these on late 70s/early 80s Japanese video equipment. I think I still have one (male) in my hellbox--used to connect to an old Japanese RGB monitor (the monitor really was Japanese--all labeling was in Kanji, except for the power input--100 VAC, 60 Hz).
 
Since this is a bare-frame monitor, I'm guessing that it was hooked to a CNC rig of some sort. 1984 is too early for a 386. It could also be a 80186 system (like the Tandy 2000).

Do you have any information?
 
I think several Japanese PCs used similar colour monitors (inside a case of course) and those connectors; Toshiba comes to mind, as well as Sharp, I think.

Indeed, more info is needed; any manufacturer names and/or model numbers on the monitor or the connected computer?

There was a sort-of-standard for those plugs, but I think it'll be a challenge to convert to VGA; no other options (like replacing the whole package)?
 
Computer is somehow connected to an elevator controller. The computer just reads serial input and then broadcasts the video of what floor the car is on to this monitor.

As for the computer, I did not get a lot of time to examine it. There was a main board and two daughter boards. One daughter was for video and the other was connected to the serial connection.

It also looked like everything was hard coded in eproms.


Replacing the old monitor is an option, I would need a source though. :)

Thanks for all the help so far.
 
Several boards show NEC on them and there is a sticker on the tube marked NEC. I have called NEC and the product is too old for their records.
 
Looks like a fairly standard open frame CGA monitor... but looks can be decieving. Look at where the video cable connects to the monitor's board, the inputs might even be labelled. Follow the circuit and see where the individual color lines go - If it was designed for computer use, then it'll probably take digital CGA, and all three will go straight to a digital logic chip. If it's analog, then they will go to an amplifier circuit.

If this is digital, then you can use any kind of common computer CGA monitor as a replacement. If it's analog, then you can use a Commodore Amiga monitor, or something similar, like the monitor for a coin operated video game.

It'll be a fair bit smaller, but you can get an itty-bitty 5" digital CGA open frame monitor for $20 from timeline - http://www.timeline-inc.com/blowout.html

Another option would be to just repair the monitor. What's wrong with it?

-Ian
 
Guys,

Thanks a million so far for all of the help.

As for the pinout, I did custom PC wiring for several years. I know that color codes are not always used in accordance with the standard wiring colors. 2 is Red wire, 3 is green wire and 4 is blue. 5 and 6 are a shared black wire. There is a white wire on #1 which is not listed on any of the codes from the link above..http://wouter.bbcmicro.net/8bit/monitors/index.html The white wire shares a jacket with a shielded wire that the shielded wire is soldered to the 5 and 6 ground. It connects to a separate place on the board below the 2,3,4 wires in the photo.

The video cable connects to the board and then runs to two TI chips. R1-R6 are the connectors from the cable. One is a J314B2 and the other is a 436ES. Here are both sides of the board where the cable connects to the board....
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I am not sure if this means this is digital or analog. I am thinking digital since there is a chip. Any confirmation would be appreciated.

The burn in on the monitor is pretty bad. It is to the point where you can read all of the stops and the name of the building on the screen. I figured that replacing it would be best way to go. I am unsure of the symptoms of why it is bad, but I do see a popped capacitor on the board. It is so old you can not read the type that it is.

Since you can tell from all of the maintenance done at this place, I was thinking bigger and newer would be better.
 
OK, yeah, definitely looks to be digital. You can see the video signals going straight to the 7400

On that video connector:

R1: Ground
R2: Sync
R3: Sync
R4: Blue
R5: Green
R6: Red

The two sync lines are both connected to the inputs of the first gate on the 7400, so they're NANDed together. So, I would assume that's your H and V syncs, and it doesn't matter which is which for this monitor.

One thing I do not see is an intensity line. Since CGA monitors are digital, you need another input to get another shade of a color. Without it, you're limited to 8 colors (one of which is black). With the intensity line, you can get 16 colors. Although, in this application, there might not be any intensity line, since it's an industrial control application, and color isn't important.

So, you should be able to wire up an adapter to plug into a normal CGA monitor. You may have to play with the syncs, since there is no way of telling which is H and which it V sync without more information.

-Ian
 
leonphelps said:
Computer is somehow connected to an elevator controller. The computer just reads serial input and then broadcasts the video of what floor the car is on to this monitor.

As for the computer, I did not get a lot of time to examine it. There was a main board and two daughter boards. One daughter was for video and the other was connected to the serial connection.

It also looked like everything was hard coded in eproms.


Replacing the old monitor is an option, I would need a source though. :)

Thanks for all the help so far.
Click to expand...

You don't show your location; I'm assuming that it's the USA. If not, please advise.

In short, you can get a replacement monitor (or even an LCD replacement) from any of the firms specializing in CNC gear repair. An email with a photo should get you a prompt response.

I'd start with Dynamic Displays

You might also get some mileage from the arcade games repair folks.
 
Chuck(G) said:
You might also get some mileage from the arcade games repair folks.
Click to expand...

I fix arcade machines... - the monitors in those are analog RGB, 15.75khz sync frequency (i.e. CGA resolution, analog video with TTL syncs). This monitor clearly uses digital video, but since I don't see an intensity line, you'll likely get the same kind of picture wether you use a digital or an analog monitor.

A word of warning on arcade monitors - they are "hot chassis", and REQUIRE an isolation transformer to run.

By and large, there are a LOT of different sorts of monitors that should work in this application. You might have to do a bit of experimenting, but I don't see any problem replacing that monitor.

You've got a lot of options - find an old CGA computer monitor and wire it in, find an analog RGB computer monitor and wire it in (like the Apple IIgs RGB monitor, or an Amiga monitor), find an arcade monitor, etc. I know that video converters exist to connect LCD monitors to arcade machines, but us video game purists don't use them, because the arcade games look like garbage on an LCD...

-Ian
 
yes, in USA.

I have contacted Jeff at Dynamic Display. Will keep you posted.

Thanks for all of the help.

Joe
 
$1250 is a little steep for my blood.

I think I am going to try this type of adapter. http://cgi.ebay.com/RGB-CGA-EGA-YUV...356?pt=LH_DefaultDomain_0&hash=item1c17e9e74c

Does anyone think this would work? The instructions say works with a CGA then I would need to hook up red, green, blue and v-synch and h-synch. I could hook this up to any old VGA monitor. With the monitor being $100 and the adapter $44, this sounds a little better for me. May need a power adapter for a few bucks too.
 
tomasont said:
RetroHacker,

I'm not quite sure what you're saying here. Could you explain this in a little more detail?
Click to expand...
He means that the chassis and ground are connected to one side of the AC power line, which can cause some impressive spitzensparken when you connect it to the ground of the computer if it happens to be connected to the other side, directly or through the protective ground third wire. An isolation transformer 'isolates' the ground so that there is no longer a direct connection.
 
Update, made a cable from the 8 pin to a vga cable. red-1, blue-2, green-3, brown-13, white-14, black to 5 (ground). Screen flickered when I connected it but got no video.

Upon further looking at the video board, there are four BNC connectors. They are marked R,G,B,W. Thinking these are the 16 bit colors that were talked about in one of the previous posts.

Guess I need to look for a CGA monitor now with 4 BNC's.

Any suggestions appreciated.
 
I'm going to pull the back off the Tandy CM-5 I have here this weekend and compare it to the pictures you posted.

It's been a while since I last repaired a CM-5 but your pictures look awfully familiar and I think it might be the same monitor.

Even at the height of monitor production, there were only a few manufacturers of them and they badged them for anyone that ordered them.
 
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