Convert RGBS to VGA

[kz9yyc123]

Hello all,

I wish to convert from RGB (with one, separate sync) to VGA video or anything "off-the-shelf".

I appreciate your time and assistance. I fear I won't have enough detail, but I figured I would take a chance and seek out sharper minds. I apologize upfront for my ignorance.

I support a chip placement machine that utilizes a 14" tv monitor (which is now obsolete). This monitor accepts R, G, B and S inputs from a proprietary video card. The vendor (based out of Eindhoven, Holland) no longer supports this model and cannot offer any technical help. Out of 6 tv monitors, 5 are no longer working. The vendor's solution is to purchase a JVS monitor for $1500. I hope I can discover a cheaper solution!

ORIGINAL TV MONITOR SETUP:
Output (machine video card): Discrete R, G, B, S with SMB connectors
Input (obsolete tv monitor): 9-pin D-shell

VENDOR RECOMMENDATION TO REPLACE OBSOLETE TV MONITOR: utilize JVC 15" color, model TM-H150CG
Output (machine video card): SMB connector on G output only
Input (JVC tv monitor): SMB to BNC adapter to "Video Line A IN".

The replacement monitor is the following:
JVC 15" color monitor, model TM-H150CG.

I did buy one, and it does work. However, I need to replace 4 monitors immediately and stock one spare for storage. Hopefully, one may be able to recommend conversion hardware or a different, less expensive tv monitor.

Again, thanks for your help!!!

 

[superfrog]

VGA (VESA DDC) pinout and wiring @ pinouts.ru gives pinout for a standard VGA interface.
You might get away with getting just a 9pin to 15 pin vga adapator, or building it yourself as described on 9 to 15 pin VGA cable pinout and wiring @ pinouts.ru

the standard analog PC monitor interface is RGB+sync, I cannot see a reason but signal level for it not to work with your signal. Mind you, you probably are going to have to find multisync CRTs to be able to do that (and they are not produced anymore), as I do not believe LCD accepts anything but a very limited subset of refresh rates (apparently 50 and 60Hz is alright on most panels). The good news is that pretty much any crt from 1997 will fit the bill. You should be able to find those for next to nothing. Might be worth checking whether a cheap flat panel would do, as they will be a more futureproof option and it might please your customers to have clean new hardware. An LCD would have the advantege of probably having an integrated frame buffer, eliminating the probable flickering you will get with low definition/low refresh rate on modern monitors.

People that actually know something about analog circuitry will probably be able to indicate the best way to ensure signal clarity and level. A linear amplifier with variable gain could be used to shift signal level if needed, I guess.
Old CRTs are so cheap, I would seriously consider wiring one straight to see if it works before doing anything complicated and costy.

---

 

[kz9yyc123]

Hello Superfrog--thanks for the reply.

I did try a cable adapter (RGB 9-pin to VGA 15-pin). Unfortunately, that did not work.

Based upon what I've read (and I stress that I'm still trying to understand everything I've read), my obsolete monitor utilizes a single sync signal, where horizontal and vertical sync signals are somehow superimposed (my machine video card has only one "sync" output). Based upon your schematic, VGA's 15-pin sub has horizontal sync on pin 13 and vertical sync on pin 14.

I thought this was my primary problem to overcome: convert from a composite sync to dual sync signals? I'm so lost at the moment, the only thing I'm worried about is figuring out something that even works, let alone ensuring good picture clarity!

Again, I appreciate your time and effort.

 

[Sceadwian]

Do you know what the signal levels of the RGB lines are? You could asume they're standard and just try to split the H/V sync pulses from the single pulses channle, if you can get a scope view of the sync output from your video device.

Basically you need an o'scope to see what's going on, or someone that knows what type of system you're using. If you can get a view of the signal and you're lucky you'll only need a few discrete logic IC's to separate them. It's obviously going to be easy to separate or the monitor wouldn't use the system.

 

[ronsimpson]

VGA sync is 31.5khz.

Likely the sync for your 14” monitor is 15.750khz.

You will have better luck using a “TV” than a VGA monitor.

 

[Sceadwian]

If he can seperate the horizontal and vertical sync pulses as long as they're in range it doesn't matter. Most VGA monitors have incredibly dynamic ranges.

 

[Mr RB]

I've got one of those cheapy $30 DVD players from the supermarket, it has RGB+sync inputs. You could use something like that to convert RGB+sync to composite video and connect to any little TV. I'm sure you could buy a RGB+cync -> composite video converter anyway.

I just googled for "component RGB to composite video converter" and there are a ton of units available.

here's a very neat little one; RGB to TV convertor - RGB to NTSC & PAL video encoder

 

[Nigel Goodwin]

I've got one of those cheapy $30 DVD players from the supermarket, it has RGB+sync inputs. You could use something like that to convert RGB+sync to composite video and connect to any little TV. I'm sure you could buy a RGB+cync -> composite video converter anyway.

I just googled for "component RGB to composite video converter" and there are a ton of units available.

here's a very neat little one; RGB to TV convertor - RGB to NTSC & PAL video encoder

Except you're going from the best possible quality (RGB) to the worst possible (Composite) - the differenc eis huge, and it may make it practically unuseable.

The OP unfortunately doesn't have his location filled in, but any TV with a SCART socket should work perfectly well if pin 16 is switched high (RGB fast blanking) - I've done this MANY times over the past decades.

 

[kz9yyc123]

Hello All,

I appreciate all of you suggestions and feedback. Hopefully, the following clarifies some questions posed earlier.

-I support surface mount manufacturing in Kokomo, Indiana USA.
-I tried a replacement monitor: JVC TM-H150CG High Resolution Color monitor. It does work.
scan frequency = H: 15.625 kHz (PAL), V: 59.94/60 Hz
composite input = composite video 1.0 V (p-p), 75 ohms, negative sync, auto-termination, BNC x2, bridged-out possible.

Fortnuately, the composite video is sufficient for the application.

My goal now is to pursue a lower cost option (i.e., less than the $1500 it cost me for this monitor). As suggested, I've looked at video converters online. I need to verify it will work with my application. Mr RB posted a RGB to PAL video converter link. I need to do some homework because I don't know how I would connect to the suggested converter. I use a coaxial cable with SMB connectors on either end.

I welcome any additional suggestions. Finally, I hope someone will explain (in layman's terms) what "negative sync" is. Thanks!!

 

[kz9yyc123]

Hello all,

Ok, after investigating composite video monitors (composite video 1.0 V (p-p), 75 ohms, negative sync, auto-termination, BNC x2, bridged-out possible), I hope there are less costly alternatives.

I use the monitor in question to visually see camera images during a fiducial inspection. High resolution and picture clarity is not important.

As suggested, I looked at video adapters. It seems there are several options. However, I cannot find adapters that will connect the machine video card to the video converter. The video card has an SMB connection on it, and several converters I looked at require RCA or S-video inputs.

I didn't see any adapters for the SMB to RCA or S-video. Any suggestions?

 

[mneary]

What is your signal source? Perhaps one of us could suggest some way to adapt it. Maybe a photo of the connectors would help.


[edit] I designed a product back in the 1980's that's still in the field. I'll see if I can find someone who knows how it's being supported.