sony ntsc monitor -- why isn't rgb input working?

I have a Sony PVM-1341 ntsc monitor as part of our fcp setup. It generally works just fine, but I have been unable to get the RGB inputs to work. I've tried sending a signal from the Kona LS card that we're using as well as from our BetaSP deck. I know that the Beta deck is sending a signal from the RGB outs because that's what I'm using to get video into the Kona with.

For my most recent tests, I used about 3 different cable combos to try and rule out the possibility of a bad cable, but that didn't seem to affect anything.

The monitor is self-terminating, so termination of the signal shouldn't be an issue. The monitor works when using the Y/C and composite connections, so it doesn't seem to be an issue of a bad tube, etc. Like I said, the beta deck is definitely sending a signal because I get video through the Kona card directly connected to the beta deck.

Where this all points to (at least in my eyes) is to a bad set of RGB connectors on the monitor. I'd be interested to know if you all have other ideas of things I might try before we have to go the route of sending this thing into the shop to get it benched.

Thanks!

Do you see anything on the monitor when you send the signal?



- Justin Barham -

Beta machines and almost everything else having to do with video don't use RGB. They all use Y, R-Y, and B -Y or Yuv or something like that. If you tell the monitor to look for an RGB signal, it will immediately try to find a signal on the External Sync input. If it doesn't find one, it will stop working. RGB is badly named. Almost all RGB systems are really RGBS and must include a Sync signal as a fourth wire.

Yuv and those variations carry sync automatically along with the Y signal.

Generally, put there is a R/R-Y input, a B/B-Y input and a G/Y input on the back of the monitor.

The green colored video cable is almost always pressed into service as Y. Hook up the Beta machine like that and then tell the monitor to look for a "Sony Component" or Y, R-Y, B-Y signal and I bet it starts working.

You can think of video components as black and white (Y), Red and Blue instead of Red, Blue, Green, Sync. Since the Y signal is made up of all the original colors, you can figure out green later.

Koz

thanks for your responses. in answer to the first question, nothing appeared on the screen when I sent a signal through the rgb inputs.

in answer to the second response, I was able to use the Y (green) cable connected to one of the composite inputs on the monitor to verify that a video signal was indeed being sent from the beta deck.

There is a "External sync" connector next to the rgb connectors on the back of the monitor, but on the beta deck, the only thing resembling that is a "timecode out" connector. I tried connecting those two, and I got the same result as before--nothing. There's a button on the front of the monitor that lets you choose between analog/digital sync (int/ext). The button doesn't seem to affect anything that I've tried so far.

Do you think there's any way to get the RGB inputs working with my existing setup? Ideally, I'd like to hook the Kona's component outs to the RGB ins of the monitor, so I can monitor my edits in high quality. But as far as I can tell, the Kona won't send sync (at least I can't figure out which cable it would use to do so), so I don't know how that would work with our monitor.

Anyway, I'd appreciate any additional ideas you can offer. Thanks!

You should probably not say the words RGB any more. Just stop forming your lips into those words. No video system other than the one to the computer monitor uses RGB (S).

The Beta machine will supply Y, R-Y, and B-Y from the back panel. I believe all but the one simple office Beta viewing machine do that. You can use the Y signal for troubleshooting. That signal is a properly operating black and white television signal all by itself. The other two are a little magic and you do need all three for a good color picture.

Everybody I know also makes one mistake that drives me nuts. Are you **sure** there is tape playback of actual video during all these tests? Once a week I rescue someone who is playing back a black tape and wondering why all the monitors are black.

I don't recognize that monitor model number, but if the connectors on the back do not say Y, R-Y and B-Y in addition to anything else, then the signals that the Beta machine supplies and the monitor inputs will never talk to each other (I don't think that's what the problem is, but anything's possible).

Go back there with a flashlight. Is there a set of three matching connectors between the two devices? No, the Time Code connector will not help. Beta component color video is carried by3 cables only.

Koz

Ok. Thanks for your response.

First of all, I am POSITIVE that there is actual tape playback from the beta deck. I have checked this several times. Like I mentioned in my previous message, I do get a video signal (black and white) when I hook the "Y" to one of the composite inputs on the monitor.

on the back of the monitor, under a "Analog RGB" bracket, are listed "R", "G", and "B"--all three with in and outs. I believe I'm starting to understand you to say that RGB is NOT the same as component (or, Y,Pb,Pr, correct?).

What I still don't understand is why the Kona LS won't communicate with the monitor as well. Is it the same issue? The Kona output cables are labeled as follows:
{Pr/R/C} {Y/G/CVBS} {Pb/B/Y}
[aja.com]

That labeling leads me to believe that it should work with the RGB connectors--or is it because that there's no separate SYNC output that it doesn't?

Thanks for your replies. I really do appreciate it. I just want to understand what I'm working with, and know once and for all whether I'm ever going to be able to use the component/RGB inputs on my ntsc monitor.

Is there a piece of equipment that could act as a go-between from the beta/kona to the monitor to allow it to "talk" between the two devices?

Thanks!

I don't think that's what's broken any more. I gotta go to work now. Later. Somebody else can jump in here while I'm gone.

Koz

Connect the Ys together. The Beta R-Y goes to the Pr and the Beta B-Y goes to the Pb. Everythng else you need to do is done with switching on the front of the monitor.

CVBS is Composite Video Baseband Signal (really just "video". That's the one you broadcast. Everything is mixed together onto one wire.

Y/C is also known as "S" video. That's where black and white (Y) and Color (C) travel down two separate wires. That's a much sharper version of CVBS.

RGB you already know about.

I've seen some really oddball switching schemes to select the right combination of signals, but that's what it's down to. If your cables are correct, you should be able to find one selector button or switch somewhere on the monitor that will give you good picture.

Consult (Gasp) your instruction book.

Koz