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NON-CRT Displays that support 15KHz and 25KHz resolutions

xodaraP said:
What's that thing? Terminals connected to a DB15HD? I need a couple of those
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I just call them VGA Breakout Terminals, either male or female. Here is the long name: DB15 Female D-SUB 3 Row 15Pin VGA Plug Breakout Terminal Solderless Connector. A few subtle variations of it depending on how clean you need the breakout to be. I think that one I linked is the cleanest. I use them to connect a Dreamcast VGA box to JAMMA and use them in place of a J-PAC so I can use joystick controls and bypass J-Pac's video amp. Wish they made something like this for SCART for that price. But that is another discussion.

Something to look forward to next week at work. There are literally tons of old monitors are sitting around on each floor in every building waiting to be tossed in the recycle bins. Don't know why I didn't think of checking on this sooner.
 
Cool, might need to order a couple, I was going to hack apart a VGA cable to make up an RGB cable to connect to an LCD (a friend built a supergun for me and it has a DB9 connector for RGB video so I was going to solder the correct connector on one end of the VGA cable)
 
Alrighty, rigged up my TPG so that I can hook it up to VGA cable. I followed the diagram on Andy Warne's site and have the sync pins (13 & 14) jumpered so both pins should have the same signal.

VGABreakout.JPG

Here is it on my Samsung 204B. The 204B seems to only like the checker board pattern on the TPG and has issues displaying it. As you can see it is shifted left.

CraftMech.JPG

I am taking this to work tomorrow to test those NEC Multisyncs that are literally crawling all over the place waiting to be recycled.

On another note, I have been messing around with interfacing console SCART RGB to an arcade monitor. As a side benefit to this effort, I will see if might be able to hook up a console (PS1, PS2, Saturn, and Dreamcast @15khz) to an LCD monitor without using a VGA conversion solution. I can use the same solution I am using to connect my consoles to an arcade monitor.
 
Not a useful monitor for 15KHz or anything, but the other day I was setting up a machine with CRT Emudriver, and was doing the initial setup with my BenQ XL2720T 27" 1080p 120Hz LED LCD and it was able to display the 15KHz 480i signal of the desktop using VGA, though not the 15KHz 240p signal when MAME was running games - that was out of range. The 480i image was incredibly flickery and text looked awful though - it was just enough to get by on the desktop. Just thought somebody might find that interesting.
 
udongein said:
Not a useful monitor for 15KHz or anything, but the other day I was setting up a machine with CRT Emudriver, and was doing the initial setup with my BenQ XL2720T 27" 1080p 120Hz LED LCD and it was able to display the 15KHz 480i signal of the desktop using VGA, though not the 15KHz 240p signal when MAME was running games - that was out of range. The 480i image was incredibly flickery and text looked awful though - it was just enough to get by on the desktop. Just thought somebody might find that interesting.
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Most times, that is just enough to get through the frustrations of installing CRT Emu. If you can get to 480i, then you can shut down and move the rest of CRT Emu installation to your arcade monitor.

Hence the search for LCD's that can properly sync to 15khz CGA resolution. Serves the purpose of using an LCD for a test bench setup, CRT Emu installation, and maybe messing around with console RGB video. Although, not much use for the latter other than curiosity.
 
twistedsymphony said:
I bought an NEC 1970NX and so far it has been able to sync to the 15K signals from a NAOMI and a System 256
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Interestingly enough, I have a ton of 19070NX on my building and floor alone. But I can't get 15khz from the TPG to work. 25khz is fine. I have more 2070NX's than I do 1970NX's. All the NEC's I have ran into this morning and tried can all do 25khz but can't do 15khz from the TPG. Perhaps I should wire sync differently?
twistedsymphony said:
as for my monitor's firmware revision:
F/W ID C59SLP10
F/W Version 1.1.10
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The 1970NX that is in front of me has an even older firmware than yours:

F/W ID C59SLP10
F/W VER. 1.1.03

Does yours work with the TPG at 15khz?
 
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it could be firmware on those monitors... check the firmware revision, as we found earlier in this thread that the newer firmwares don't work with 15KHz and need to be downgraded.
 
So far, I have only found one 1970NX. I'll scrounge around for some more. Hopefully, I can find one with firmware version 1.1.10
 
To be fair, on mine I mostly tested with NAOMI and Sys256 in 15K mode which are both 480i. I did go through with a CRT_EmuDriver PC at one point and tested every mode available (I think posted or linked to my results from this somewhere in the thread) there were a few unsupported or unstable modes but the vast majority worked. I've used this monitor to help setup/troubleshoot a couple of CRT_EmuDriver setups as well and never had a problem with it there.

I've never tested with the TPG or an actual JAMMA board though. so all of my sources supplied separate H and V syncs.
 
I saw that post. No worries. If you get a chance, see if you can get 15khz from the TPG to display on your 1970NX. Because.......

1970NXProperFW.JPG

..........I found a 1970NX with f/w 1.1.10, and while it likes TPG's 25khz, it doesn't like TPG's 15khz. You did mention that you have separate H and V syncs, but damn me today. I only have the TPG set up for CSync. But if we truly are to use this monitor as an LCD on a JAMMA test bench, looks like we might have to build a sync separator circuit since most JAMMA boards output composite sync?

I won't be able to mess with this separate H and V sync till this weekend. But am happy I found one of these 1970NX monitors. Hopefully, the powers that be won't mind if I take it home with me.
 
Alrighty, made a harness for the TPG so that I can get H and V synch separately. The 1970NX wasn't able to sync to it. So I hooked up the Naomi at 15khz and got instant video:

VirtuaTennis15khz.JPG

I noticed that the 1970nx states that the H and V are negative synch. So I wired up the TPG on the -H and -V pins hoping to get a signal from it. No luck. I am hoping is an issue with the dip switch settings on the TPG. I'll have to fiddle around with it some more till I figure it out. It may just be that the the 1970NX doesn't like TPG's signal. That would be bad though since that is the same as a JAMMA signal. No JAMMA signal means it is worthless for a test bench LCD monitor.

Also hooked up my Dreamcast via RGB modded VGA box to the 1970NX. Got instant sync there too.

DreamcastA15khz.JPG
 

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How exactly was is failing? were you getting a sync out of range message or something else?

I have a TPG but not a VGA cable for it. I just ordered a VGA breakout so we'll see if I run into the same issue with mine.
 
twistedsymphony said:
How exactly was is failing? were you getting a sync out of range message or something else?
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Complete blank screen. "No Signal D-Sub" message. Weird that it loves 25hz though off the same pin output from the TPG.

Let me know when you get yours going if you can display anything other than the checker board screen at 25khz. On mine, the next pattern just flashes, then it returns back to the checker board pattern.
twistedsymphony said:
I have a TPG but not a VGA cable for it. I just ordered a VGA breakout so we'll see if I run into the same issue with mine.
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The last thing to do is to disable composite sync output on the H pins and just send a pure sync signal. Sucks though since you have to do that in the menu which is only available at 15khz on the TPG. I have to rewire the harness again now before I can do that.

Of all the outcomes:
  1. Best case scenario, once composite sync is disabled in the menu, the TPG can accept pure sync signal off the H pin(s) alone. This replicates what a JAMMA board would output. I am thinking this is a pipe dream though.
  2. Next best thing is that disabling composite sync allows the 1970NX to show a 15khz signal being feed separate H and V sync. But now if we are to use it for a JAMMA test bench monitor, we have to figure out how to create a sync separator circuit that can output negative sync over H and V.
  3. Worst case scenario, it can't take JAMMA signal at all.
 
acblunden2 said:
we have to figure out how to create a sync separator circuit that can output negative sync over H and V.
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Sync Separator ICs are cheap and easy to get. you'll want to have a small circuit for JAMMA anyway since the R G and B lines will be at 4V instead of the 1V that VGA expects... but this will be true of ANY monitor not explicitly built for Arcades.
 
Not the cost of the sync separators that scares me. It is the building of the circuit. I can't even build legos :P.

Ok, so the 1970NX does not like TPG's 15khz signal. I triied ever possible configuration. I know my K7000 likes it. Here is to hoping it is just a TPG thing. Will try next to see if an actual JAMMA board produces different results.
 
Alrighty folks.........my tests finds that the 1970NX cannot accept JAMMA 15khz video.

Snipped RGB, VGND, and Sync from one of my cabs with a K7000 monitor's chassis. Fed Sync into Pin 13 on the VGA breakout on one test. Fed Sync into Pin 14 on another test. On all tests, R was on pin 1, G was on pin 2, B was on pin 3, VGND was on Pin 5. Checked for continuity from the JAMMA harness with a labled fingerboard. Finished off the connection with an OEM NAOMI VGA cable. Fired up the cab and just got a black screen. Turned the monitor on and off to see if it would make a difference; nope. Sound was coming off the cabs speakers, so the game was working. This coupled with my tests using the Crafty Mech TPG where I split sync into every possible configuration confirms that the 1970NX can't handle arcade 15khz

My guess is that JAMMA 15khz voltage is too high for the 1970NX. Dont' know why it likes 25khz video however. Also, I suspect the I/O boards used with NAOMI's are amping the signals before passing them off to JAMMA. Hence why NAOMI works. This is just speculation however. There is the possibility that I have a 1970NX that is defective somehow. So will wait for what @twistedsymphony finds for a 2nd expert opinion, before crossing this monitor off the list.
 
If the voltage is too high, would a resistor work? It certainly takes it away from plug and play status but still
 
That part is just speculation about the voltages being too high. But yeah, that is the point; just finding a monitor that will work outright. I mean JAMMA to VGA convertors can be found anywhere.
 
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