X68000 RGB, Many questions...

[cdoty]

The X68000 in low res seems to be a nasty beast..

I can see video in normal mode, on a VGA monitor, but can only see scrambled video on a few VGA monitors.

I tried hooking it up to a arcade RGB monitor, and a Commodore 1084s. The Commodore 1084 does show something if the HSYNC is grounded, but it's definately synched correctly. I didn't seperate out the HSYNC and VSYNC for the arcade monitor, would this help? I also have the same problem with a PlayChoice 10 board on the 1084 monitor.

Any ideas on connecting the X68000 (PRO) to a monitor that will support low res?

Would something like JROK's RGB decoder work?

[NFG]

1. The X68000's RGB, in 15kHz (low res mode) is no different than any other low-res RGB device.

2. I have succes joining the H+V lines together for C-Sync devices.  YMMV.

3. Your question "Any ideas on connecting the X68000 (PRO) to a monitor that will support low res?" is so vague it's not answerable.

4.  You can't decode RGB.

5. You shouldn't post the same question more than once.  I'm combining the threads.


Other thread:

Is there a way to display the X68000 low res output

You don't mention what your problem is with this signal.  Hard to tell you what to fix if we don't know what's wrong.

[cdoty]

1. The X68000's RGB, in 15kHz (low res mode) is no different than any other low-res RGB device.

So, there should be *no* reason that a Commodore 1084, would display it? (Barring miswiring).

There is a difference between low res devices. An arcade monitor has two inputs for sync (positive and negative). The PlayChoice also uses a 15khz RGB device, but the colors are inverted. This is the *critical* information I am after.

I could ask about a specific monitor (Commodore 1084 in my case), but that could eliminate a helpful hint from someone who hooked it into another model RGB monitor.

3. Your question "Any ideas on connecting the X68000 (PRO) to a monitor that will support low res?" is so vague it's not answerable.

I'm hoping someone has found a monitor that will work with the X68000. I was hoping for somethhing like: NEC Mulitsync 3DS will work with the X68000.

4.  You can't decode RGB.

Ooops, encoder. It's the product name (http://www.jrok.com/hardware/RGBv4/)

Other thread:

Is there a way to display the X68000 low res output

You don't mention what your problem is with this signal.  Hard to tell you what to fix if we don't know what's wrong.

I don't know what the problem is. I described what I saw.. The sync isn't correct. The colors are off, but this is probably related to sync. I sure it's something stupid...

I can get it to display a very fuzzy and non-centered image if I ground the HSYNC.

[cdoty]

Ok, let me start over:

I have attempted to hook the X68000 into a Commodore 1084 (standard RGB monitor).

I connected the X68000 Red, Green and, Blue lines to their associated lines on the monitor (Pins 1, 3, and 5 to Pins 1-3). I've based my X68000 connection on this diagram http://www.gamesx.com/avpinouts/japan15rgb.htm

I'm assuming this is as viewed from the back of the computer, since the diagram appears to be drawn as a female connector.

And, the RGB monitor connection on this diagram:
http://www.technick.net/public/code/cp_dpa...convid_c1084_ds

This is from a cable that plugs into the monitor, since it's also female.

I connected the X68000 Red, Green and Blue grounds together and connected them to the grounds on the monitor connector (Pins 2, 4 and, 6 to Pins 1 and 2).

I'm not sure about Pin 8 or Pin 12 on the X68000 connector. Pin 8 would seem to be the ground for the computer present line, and Pin 12 would seem to be the ground for the audio.

I tried connecting the HSYNC and VSYNC (pins 14 and 15 to pin 7) various ways. Nothing seemed to work.


Now for the questions:
1) Are the sync signals between X68000 and 1084 the same (not inverted)?

2) Are the voltage levels the same?


Any suggestions or help would be greatly appreciated. I'm at a loss for solving this problem.

[NFG]

OK, let's work through this:

I have attempted to hook the X68000 into a Commodore 1084 (standard RGB monitor).

There are several models of 1084.  Some, like the 1084D, are quite finicky about the signals they accept.  Mine wouldn't work at all with a Neo MVS PCB, but my 1084S worked more or less fine, albeit with a wicked top-curl.  I'd have bet money it'd work with an X68, but I don't have one to test with.

There's no such thing as a 'standard RGB monitor'.  It's a cross we all bear.

I'm assuming this is as viewed from the back of the computer

The numbers are marked right on the connector.  Get up close and have a look.

I'm not sure about Pin 8 or Pin 12 on the X68000 connector. Pin 8 would seem to be the ground for the computer present line, and Pin 12 would seem to be the ground for the audio.

You don't need to worry about the Ys (Data Present) output on the X68, it's a +5v line to signal the monitor there is a signal available.  As for ground, they're all the same.  It's a good idea to connect them all.

Are the sync signals between X68000 and 1084 the same (not inverted)?

Only weird hardware uses positive sync (like old Williams arcade PCBs (JOust, Robotron).  Negative sync is the standard for all other applications.

Are the voltage levels the same?

Voltage levels are the same.  Again, excepting weird hardware 0.7V p-p is the norm for RGB signals.

If your monitor has H+V inputs, you should probably use the H+V outputs from the X68.

There is a difference between low res devices. An arcade monitor has two inputs for sync (positive and negative). The PlayChoice also uses a 15khz RGB device, but the colors are inverted. This is the *critical* information I am after.

This exposes some wicked assumptions:
1. Not all arcade monitors are the same.  Not all of them have + and - Sync inputs.  
2. The PC10 monitors also included inverting PCBs so they could use normal PCBs, or the PCB could be used on normal monitors.  There's exceptions to every rule.

[Midori]

Does your monitor have H- and V-sync inputs or a composite sync input? If it has a Composite sync input it'll probably want composite sync and not just V sync or just H sync.

[cdoty]

Does your monitor have H- and V-sync inputs or a composite sync input? If it has a Composite sync input it'll probably want composite sync and not just V sync or just H sync.

The 1084(D) has only composite sync in Analog RGB mode.

[cdoty]

Problem solved, mostly.

I found a Mitsubishi Diamond Scan 16L, which works fine on both modes. Nekketsu Koukou Dodgeball-bu works great.


It does have some problem with games such as Puyo Puyo, which uses a 320x224 display mode.

The image looks correct, but the edges of the screen are displayed in the center of the screen.

I'm not sure how to correct it, the horiz. and vert. only adjust the image so much.

Anyway, all works well enough, I could adjust to high res mode.

[viletim!]

cdoty,
For combining TTL horiz. and vert. sync signals (-ve polarity) give this a try

It's not 100% effective but it's much better than just connecting the wires together.

If the sync polariy changes (I'll admit that I've got no idea what an X68000 is, let alone know about it's video output) then maybe try this one.

[Hoping to get my own X68 someday]

Will the Philips CM 8833-II work OK in low res with the X68000 line of computers?
Heres the tech specs:
http://www.amiga-hardware.com/showhardware.cgi?HARDID=880

[ido8bit]

The Phillips CM 8833-II is basically the same monitor as the Philips made 1084S.  There is a "family" of monitors that all use basically the same Philips made chassis.  These include some versions of the 1084S, the CM8833-x, an Atari ST monitor that I forget the model number for, the Acorn AKF14 (from memory, that model number may be wrong).  These are not hard to find around here and should also be relatively common in the UK and Europe.  I don't know how easy to find they are elsewhere.  I do know that in some places the Toshiba made version of the 1084S is far more common.  

NONE OF THE FOLLOWING APPLIES TO THE TOSHIBA 1084S.

These monitors are quite tolerant of what they will display.  I have used them successfully with many many different computers and consoles.  Including some known to output something the isn't quite standard (TRS-80 color computer 3, DECmate, etc).

While am I not familar with the X68000 as long as you wire the cable correctly it should work.  You will need to combine the H/V sync into C sync as the these monitors only have a Csync input.  If the X68000 has a composite video output you can use that as these monitors will accept composite video as sync.

When wiring a cable keep in mind that different versions of the 1084S have different pinout, make sure you are refering the the right pinout for your monitor.  

[Endymion]

Is there a list anywhere of what games do what modes? I have only played a handful on mine but when I first got my X68000 from our esteemed benefactor all I had to do was modify one end of the cable to VGA and voila. Thunder Force II works perfectly with a VGA monitor, *and that's what's important to me.

The only time I ever tried running a 15KHz RGB signal (Genesis) to a VGA screen (a 22" Philips VGA CRT, way back in 1993) it functioned, and gave a picture that was scaled properly to fullscreen, but with downward-rolling horizontal black/blank lines a few cm high, I figured it was not good nor did I want to play the thing that way so I just packed it in til I could get an RGB monitor that could do 15KHz sync. I haven't seen anything like that with my X68000 yet though, and I have yet to make a connection to my 15KHz monitors.

*anybody got Nemesis '90 for sale?