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Help with an old monitor

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Wait, what? You're trying to use a CM-1? That's a Tandy 2000 monitor. You need CGA. I don't even know of anything besides a Tandy 2000 (or one of the Tandy video cards) that can drive a CM-1.

Repeat after me. CGA. :D

-Ian
 
Sorry Ian, I am working with info I get from others. I am trying to use a CM-5 monitor. I was using the pinout from the CM-1 so I knew what the pins are on the hirose connector. Is the Tandy CM-5 a CGA monitor?
 
leonphelps said:
so any recommendations with where to go with this?
Click to expand...

Connect a CGA monitor to the elevator controller.

The signals are clearly digital, since they go straight to a couple of TTL logic chips on the monitor's board. You keep going off on tangents trying to match up connectors, but that square 8 pin connector was never standardized. Just because a Tandy CM1 or some other monitor used it, doesn't mean another system using the connector used the same pinout. I've got monitors that use it for analog RGB, and I have some VTR equipment that uses it for composite video. Likewise, you mention this square connector, and BNC connectors, and the connector on the monitor's chassis - but I don't know where or in what order these connectors exist on your system. That 8 pin connector might be a dead match for the pinout of a CM1... it might not. No way to tell without looking. Follow the wires and see where they go. Since you were able to get some kind of video on the CM1, then it might be the same pinout. In which case, building an adapter cable to a CGA monitor is trivial.

When you got a picture on the CM1, were all the colors there? Was it recognisable to what you were expecting to get, just out of sync? If so, then it's more than likely the right pinout, and your above cable should work.

Since I have never seen this system, I don't know what the wiring looks like. But, to generalize, between the controller/computer and the monitor, there must be some kind of cable. In that cable, on whatever connector it uses, is going to be the three colors, sync signals, ground, and probably an intensity signal. You need to find these signals and connect them to a compatible monitor, which, I'm making an educated guess is probably CGA, based on the interface and the application.

Based on the photos you initially supplied, I tried to give you the pinouts back in the second page of the thread, but I also don't know where all the wires in the video interface cable go. You mention another connector that plugs in elsewhere - but don't say where that is or show a picture of it. That might be your intensity line (it'll go to the video amplifier circuit somehow).

-Ian
 
Another thing to watch out for is that occasionally I've seen things with inverted sync signals. If you get a picture that fills the screen and is intact, but you can't get it to stop rolling (not a torn/doubled up image, a rolling one) - the syncs might be inverted. You can use a 7404 or similar inverter gate to invert them back.

This system might use composite sync - it might not. The old montior seems to combine both syncs together... but they may exist seperately in the cable (they probably do)

One thing I just thought of, is that if you were to find an old NEC multisync montior - either the original Multisync, the 2A or the 3D - those will sync to damn near anything...

-Ian
 
The problem with the CM-1 was not pin configuration, but Sync frequency. Seems that the CM-1, as I found out, after the fact, has a HSync frequency of 26.4KHz which puts it somewhere betwen EGA and VGA. I knew that the CM-1 was a bit odd, and might need the Horz. osc. cranked down a bit, but, I never thought it was almost twice the standard CGA frequency. Explains why it was such a damn good looking monitor though.

I was working with the OP to make a 4 BNC connector (RGBI) to a db-9 female so that the CM-5 db-9 male could be plugged into it.

With only 4 signals to work with, I was hoping that the CM-5 would either "sync on green" or we could steal the 15.750KHz signal from the G pin and us it on the HSync pin if the monitor needed a discreet input on that pin.
 
Druid6900 said:
I was working with the OP to make a 4 BNC connector (RGBI) to a db-9 female so that the CM-5 db-9 male could be plugged into it.

With only 4 signals to work with, I was hoping that the CM-5 would either "sync on green" or we could steal the 15.750KHz signal from the G pin and us it on the HSync pin if the monitor needed a discreet input on that pin.
Click to expand...

Where in the chain are these 4 BNC connectors? I thought the original monitor had that 8 pin square connector on it. Also, from looking at the photo of the board, there appears to be video and sync on the plug at the monitor chassis (they go straight to TTL gates, nothing I see to pick the sync off the green).

-Ian
 
Ian,

Sorry if you were kept out of the loop. The board has four BNC connectors marked R,G,B,I on it.

Here are photos of the board.

100_2057.JPG

100_2058.JPG

100_2062.JPG



Thanks for all of the help guys.
 
Boy, this is turning into quite the saga... Sounds like a normal 15KHz RGBI CGA monitor but with sync-on-something (usually green). Looks like 6 connections on the board; assuming Red, Green, Blue, White and Black are Red, Green, Blue, Intensity and Ground, where does the sixth pin go?

And have we got this right: one end of the cable has 4 BNC connectors (R/G/B/I) going to the controller, and the other end has a female EIAJ-E8M connector which mates with a male on the monitor?
 
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the FOUR Bnc connections are on the mainboard. The original monitor did have the hirose connector on it. I also most recently tried a CM-1 monitor.

Basically, I could not stop the video from rolling with the adjustments on the CM-1 monitor with the hirose connector.

YES there was a cable in the middle that went from BNC to hirose.

The only BNC type cable I have left is RG59, the stuff for surveillance cameras. It is solid core and braid/foil shielded.

We gave up on the board on the bad monitor because of the burn in. We are trying to connect a CM-5 that has a DB9 connector on it.

I would still need the pin configuration to make the cable to convert.

I forgot to mention to Ian in a previous post that yes there were colors and the video was rolling, I could also make out numbers and some of the necessary lines, but they were way out of whack and adjustment did little on the monitor.
 
leonphelps said:
...I would still need the pin configuration to make the cable to convert.
Click to expand...
AFAIK the CM-1 signals are the same as a PC's CGA:

CGA CM-1
1 5 GND
2 6 GND
3 2 Red
4 3 Grn
5 4 Blu
6 1 Int
8 7 Hsync
9 8 Vsync

As you can see a CGA monitor uses six signals but you only have four coming from the main board, so I don't think it's just a matter of pinouts, but separating out the sync signal(s) somehow; maybe I missed it, but how did the 4 BNC cables originally get connected through the EIAJ connectors to the 6 pins on the monitor PCB?
 
RGB + Intensity; sync-on-green. Many NEC monitors (both CRT and LCD) can be configured for SOG. The one I'm sitting in front of right now (a Multisync 2010) is such--even has BNC connectors on it.
 
Since this is a TTL monitor, you might be able to rig up a voltage divider that pulls the RGB signals lower. I wonder if there's a stock NEC monitor that takes RGBI?

I'll do some checking.
 
OK, I thought I had this all straight, but, now I'm not so sure.

On the original cable, (the 4 x BNC to Hirose 6 + 2), did any other cables from the computer attach to the Hirose connector that attached to the original monitor?

In other words, on the end that attached to the monitor, were there more than 4 wires (I expect that a couple of the ground wires from the BNCs attached to the grounds on the Hirose), but were there any others?
 
Druid6900 said:
...In other words, on the end that attached to the monitor, were there more than 4 wires (I expect that a couple of the ground wires from the BNCs attached to the grounds on the Hirose), but were there any others?
Click to expand...
Yeah, that's what I've unsuccessfully been trying to find out, but it probably doesn't really matter; looks like he either has to find an RGBI SOG monitor, or buy or build an adapter to a CGA, VGA or another 'standard' monitor.
 
Not necessarily. He has 2 monitors at the moment, a CM-1 and a CM-5.

The CM-1, as was mentioned, has a HSync of 26.4 KHz, much too high for CGA and you'd have to increase the standard CGA frequency from the computer by a little over 59.5% to sync with the monitor. Not an impossible task.

The CM-5 has an HSync of 15.750 KHz, or exactly CGA and I think we are going to find that there were 2 or 3 more wires attached to the Hirose connector to the monitor carrying the H + V sync signals. In this case, it would just be a connect-the-dots type of operation.

The thing we DON'T know, at this point, is what frequency is the computer putting out? We seem to be assuming 15.750KHz HSync.
 
Druid6900 said:
...The CM-5 has an HSync of 15.750 KHz, or exactly CGA and I think we are going to find that there were 2 or 3 more wires attached to the Hirose connector to the monitor carrying the H + V sync signals. In this case, it would just be a connect-the-dots type of operation.
Click to expand...
You're probably right, that the original monitor's Hirose/EIAJ connector carries the sync signal(s) and it may well even match the CM-1's pinout, but if there are only four signals coming from the computer and the fourth signal is Intensity (as the "I" would suggest) then where's the sync signal if not on green? In that case you'd need a compatible monitor or a sync separator or converter.

Alternately the four signals could be RGBS instead of RGBI, which would make it much simpler.

In any case it might have been helpful to know how the four cables from the computer connected to the Hirose connector, and from there to the six pins in the old monitor, but then we wouldn't be up to 60 posts with no doubt many more to come ;-)

Yeah, we're assuming that it's a standard 15KHz signal, but then I'd expect serious tearing instead of just rolling but legible numbers on the CM-1...
 
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