Funny (theoretical) way of hooking up to an arcade monitor

[Harry Potter]

This one is for anyone with an Amiga Genlock (or someone who wants to buy one for a couple of bucks)

Most Amiga Genlocks have the following video ports:
Composite in/out
RGB in/out
Mono composite out

Here is what could be done in theory.

Get a PC video card with TV out and connect it to the composite input of your Genlock.
Then simply tap the RGB and Sync signals from the RGB output and hook it up directly to the Arcade monitor. (see pinout diagram)

This should work in theory since the RGB out port normally goes to a 1084s monitor which has a fixed Horizontal frequency of 15.625khz. (Also Genlocks can handle 50hz and 60hz Vertical with certainty and maybe even 15hz up or down)

Also some Genlocks (such as mine) have colour, contrast etc. knobs which could eliminate the hassle of screwing around inside your monitor with the settings.

Now I can hear you all say: "Isn't it a bit of a trade off going from composite to RGB??".
Yes it is but from what I can see, this is fairly simple. Simpler than many other ways i've seen. You simply go Composite -> Genlock -> Arcade monitor without touching your PC directly.
AND you don't have to use any funny hacks on your PC. Just go into TV mode and that's it
AND AND you get a theoratically perfect 15khz RGB signal done completely through hardware.
AND AND AND the image might have a more TV like look to it which some people prefer.

I don't know about resolutions but it you could probably go as high as 1024 x 768 since all (PAL) TVs operate at 768 lines in full overscan which is what Genlocks were most definitely designed for. 640 x 480 should be a certainty.

I might try this method as soon as I get my hands on a computer with TV out capable card, otherwise I'll just get an Avermedia i-micro and be done with it.

I'll also see if I can feed a 31khz signal into the RGB input and get 15khz out although I don't know if Genlocks can act as scanrate convertors. One bright note though, they can apparenly remove Macrovision encoding.  

ONE last thing (promise   ) ,it might also be possible to tap just the horizontal sync from the genlock and combine it with a 60hz Vertical signal from the PC card which means the composite thing could be bypassed completely. I'm not really an electronics wiz so I'm probably completely wrong.

I'll post a success message if all goes well or my next of kin will post my obituary if I kill myself in the process.

In the meanwhile, have fun and keep on MAMING.

[SNAAAKE]

if you kill yourself then dont come back and say.." I should have not done this".

If you are do succed then we'll buy you beer .
let us know how things work out.(seriouslly )

[Dave_K.]

if you kill yourself then dont come back and say.." I should have not done this".

I think I just found my new signiture.  Snaaake that is so funny!

[SNAAAKE]

hehe...well the dude's got a point here.I wish someone tried this.I am too afraid and I do not have any arcade monitor.

[Dave_K.]

Even if it did work (and gave you RGB from composite input) its not going to look to pretty.  You can't expect to get pure RGB out of composite...there is just too much signal degredation.   I think it was mostly used to convert in the other direction (for Amiga TV/composite recording).

But hey, if you already have one of these genlocks, go for it.  But if you have to buy a video card with tv out just for this, you might as well buy a video card that can output 15khz rgb via powerstrip!!  Or Andy's card rgb card!

You also seem to be seriously confused with what PAL and SVGA resolutions are (and their sync rates). It doesn't work like that.

[Harry Potter]

True, I could buy a card that outputs 15khz direct but I am very wary about building a computer and then plugging it into something about 10 years old and not designed for being plugged into computers. That aside, I will try to plug it direct using Powerstrip but that's being reserved for later.
Plus it would be a bit of a bonus to be able to use it as a video jukebox or even dare I say karaoke (sad sad sad).

On another note, there has already been some measure of success.

I've managed to get a power supply for the Genlock, and fed a DVD composite signal into it and output it to the 1084s monitor in RGB mode. The image actually seemed to look better through the genlock than directly, since the Genlock also acts as a very primitive time base corrector. It also stripped the Macrovision signal off and I was able to record it to VHS but that's just a side benefit.

The colour, contrast, illumination (brightness) and fade all worked perfectly and it even has a pos/neg switch for the sync. Not bad for $50 Australian.

And no I am not confused with what PAL and SVGA is. I was merely speculating on what sorts of frequencies and resolutions the Genlock might be able to accept. Maybe the wording was a bit wrong but that's what the point is.
Anyway I read in the manual that it is also possible to plug the RGB in port into an Amiga 3000 31khz video port. Who knows how high the signal could be pushed.
Now that I look at the post, the maximum 1024x768 resolution I was reffering to was the res I wanted to push through the TV output into the Genlock. My mistake in wording. I would not even dare sticking this into the Genlock RGB (kaboom) or the Arcade monitor (KABOOM!!).
Also it seems the output is dependant on the input. If your vertical input is 50hz then the RGB and composite will output PAL and 60hz will throw out NTSC. This was tried out as well so I can't use it as a PAL->NTSC converter.

I'll plug it into the arcade monitor on Friday and see what happens.

[MameFan]

> AND AND you get a theoratically perfect 15khz RGB signal done completely through hardware


No, you get a crappy converted COMPOSITE signal downgraded from pure RGB, then pushed back up to RGB to the monitor.


Why would you want to go through TWO conversions from your video card?  YUCK!


Just get an amplifier  (or hack 3 transistors+resistors and a 5 volt DC power source and a 5 volt power regulator (7805)) to up the .7 volt computer RGB signal to a 4 volt signal for the arcade monitor, and tada.. you retain "PURE" RGB signals without all this conversion involved.  

Yes, of course you need the video card that can sync to 15 KHZ, but if it has TV Output, then it likely can.

[Harry Potter]

Experiment 1 is complete. (resounding success)
I managed to hook the Genlock up to the arcade monitor and got a picture. I used my VCD  player as a video source and got an image (about 25 of them per second). Couldn't stabalise the image at first but then realised one of the sync switches on the monitor PCB was in the wrong position and voila, Captain Baldy from Next Gen was performing on my Mortal Kombat machine.
ummm.... to be quite honest, I didn't exactly 'realise' one of the switches was in the wrong position. I just messed around until the Enterprise stopped going up and down.

The picture quality was excellent. A bit non green but that can be fixed later. Better than I expected otherwise.

In answer to MameFan, I don't see just how much crappier an arcade monitor from 1990 can be so even if I plugged the computer directly into it (which I will do once experiment number 2 is complete), I doubt I would be much better off than with composite.

Anyway, as for experiment number 2, I will attempt to hook someone else's computer into the RGB input on the Genlock and see if it can convert a 31khz signal like it says in the manual.

Bye for now.

[Harry Potter]

Oh Well.

Experiment number 2 was only a success if you like looking at an image resembling a hurricane.

Therefore experiment number 3 will not happen and I'm leaving it at that.
I might try hooking up an Averkey 300 in VGA -> Scart RGB later.

At least it still works in composite to RGB mode.

Bye

[Harry Potter]

Hi,

Just one more thing. Here is a link for a neat little toy I just found. I think this one is a PAL version.
http://www.allthings.com.au/Monitors/vga%20to%20video.htm

Heaps cheaper than an Averkey300