JAMMA compatible MAME cabinet : Feedback please

[ma70ltd]

Hi All,
I am new to the forums (well as a poster anyway), So first I'd like to say hello.
I am a 23 old IT graduate, from Sydney Australia, Working in wait for it.....IT.

Have been planning my JAMMA compatible MAME cabinet for a while now.

I think I have everything sorted out and all the research complete, but before I go out and start getting all the parts together I thought I would run the plans by your wealth of knowledge in the hopes that you can spot any flaws in it(If any

[ma70ltd]

OK I'm going to assume no one can be bothered going to the link and downloading the file:

so heres the pic -- the pic looks pretty unclear(Thanks to the auto resize),
But you should still be able to make out all the components.

[BobA]

You are not making use of the jpac for your computer vga cable.  This means you wont get the benefit of the jpac video amp or the signal freq checking.   Could you run the vga to the jpac and use the rgb ouput from the harness to feed your rgb to video converter.  Then you would not need the svideo switching.

BobA

[ma70ltd]

 
Good point

I'll explain why I didn't run VGA through the J-PAC.
From what I understand the benefit of this voltage amplification/checking is to satisfy arcade monitors which run at 15khz.
So my thought process was that if I am using a standard TV(50-60 KHZ) then the signal amplification is not neccasary.

But from what you have written if I route the video through the J-PAC then I wont need the S-Video adapter. The only question it leaves me is - Will the amplified video signal be okay to run on a TV?

[CheffoJeffo]

OK I'm going to assume no one can be bothered going to the link and downloading the file:

Jumping the gun a bit ... it was only 90 minutes ...

I can't figure out why you would want to drive a TV in a JAMMA cabinet (designing a cab around an existing PC, perhaps ?) ... makes more sense to me to use an arcade monitor and an ArcadeVGA. I assume that whatever RGB converter you're using will handle the frenquency difference.

It also appears that you need to sort out the amplified JAMMA audio vs. unamplified PC audio (assuming you aren't using a sound card with built-in amp).

I'm not trying to be a naysayer, because I find the idea interesting ... just strikes me as much more complicated than it need to be (but that could be a result of what I am used to doing).

Cheers.

[ma70ltd]

Thanks for the input CheffoJeffo.

Maybe I was a bit unclear in my first post.

I'm actually building a Cabinet from scratch - primarily to run MAME, but I also want to add the JAMMA compatibility, hence why I am running a TV - and note that arcade monitors are hard to come by second hand in OZ, otherwise I would have gone the arcade monitor route.

And as for sound, I plan on using an amplified sound card, that way it should be fine to run sound for both the MAME machine and the game PCB's.

[RayB]

arcade monitors which run at 15khz.
 a standard TV(50-60 KHZ)

You're wrong. You're mixing up vertical and horizontal refresh rates.

[CheffoJeffo]

arcade monitors which run at 15khz.
 a standard TV(50-60 KHZ)

You're wrong. You're mixing up vertical and horizontal refresh rates.

He's not alone ... I  goofed (in my head at least) thinking that TV had horizontal scan rate of 30 kHz instead of 15.75 k
Hz ..

ma70ltd: I get it now ... will be intrigued to see how it works out ... wonder what kinds of resolution issues you'll run into. Keep us updated.

Cheers.

[ma70ltd]

arcade monitors which run at 15khz.
 a standard TV(50-60 KHZ)

You're wrong. You're mixing up vertical and horizontal refresh rates.

You're right, My mistake.
But that shouldn't affect my project plan.
I should be fine running the video feed from the J-PAC/JAMMA harness and running it through the RGB-> PAL video convertor - as per Jeffo's bit of advice

I guess in the end it comes down to : I either have to buy an arcade VGA card or just build an S-Video double adapter. I think the latter will be cheaper for me.

Thanks Jeffo, Ray and Bob for your feedback Will keep you all posted