resolution in regards to dual sync 15/24khz

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Mikeosoft
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resolution in regards to dual sync 15/24khz

Post by Mikeosoft » March 31st, 2011, 5:32 am

Hi,

Skipping the story here's the short:

My cab is synced right now at 15khertz at a resolution of 800x600

Is this ok? were there monitors that ran at this rate, which could not sync with 640x480? What happens when i play a cps2 game? shouldnt it not fit the full screen if this is true?

Is there no way to get my monitor to accept 640x480 or am i missing something?

Full Story:

I recently purchased a namco cyberlead cab with a replaced monitor and chasis, and inside the machine a previous owner had a shotty pc from early 2000's, a Jpac and assorted wiring mess. I gutted out the pc and thought nothing of it, but the past week I've been thinking I'd like to try some SFIV on this cyberlead.

I installed a custom (assembled from a heap of junk parts) p4 mobo and small hd running xp and got soft15k and found an old ati radeon x300 pci card from a dell from 2004. I configured the system on an lcd monitor and when it was all put together and software os all done, fired up soft15k and enabled 15khertz mode. turned off the sucker, and set it up in my cyberlead cab.

I plugged in the jpac, being sure to jumper 15k pin

it synced after the windows xp screen just like it should, only there was extreme flicker. I had assumed since I play CPS2 games in the cyberlead, that 640x480 resolution @15 would sync with no probs.

But low and behold half way down the screen there was flicker and 4 ghost images vertically going form top to bottom. Sync issue. The jpac sync in and sync orange and green leds were lit for sync ok, which meant 15k is enabled.

Annoyed with myself I tried the pc in my tri-sync naomi cab with a rodotron 666a neck, and it synced fine at 640 x 480. no probs

So I tried one more thing: While on the rodotron screen i changed the resoluton to 800 x 600 . On the rodotron this left the sides and corners cut off as I imagine it should.

I turned off the rig, plugged it back into my cyberlead and powered it on. It booted up, windows came up in 800 x 600 15khertz everthing is fine. Just had to adjust the size of the screen and i cant change the curving of the center part of the image, kinda like a buldge, but i'm ok with it.

My cab is synced right now at 15khertz at a resolution of 800x600 and everything fits just fine. There is a small amount of flicker noticable with my eye when reading text on a bright white background, is this normal?

Is this ok? were there monitors that ran at this rate, which could not sync with 640x480? What happens when i play a cps2 game? shouldnt it not fit the full screen if this is true?

Is there no way to get my monitor to accept 640x480 or am i missing something?

Mikeosoft
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Re: resolution in regards to dual sync 15/24khz

Post by Mikeosoft » April 1st, 2011, 6:38 pm

hmm maybe i'm asking this incorrectly. I'm going to try to find which monitor brand I have maybe that will yeild some answers,

I just would like to know, would it make sense that an arcade monitor made circa 1998 (medium refresh era) would have a native sync resolution of 800 x 600?

I just dont understand how when I throw in a CP2 mobo it syncs perfectly, I'm assuming the cps2 is not outputting an image 800 x 600 pixels correct?

will reply with my monitor chasis make and model

fagin
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Re: resolution in regards to dual sync 15/24khz

Post by fagin » April 1st, 2011, 8:02 pm

Unless I am missing something I thought that the sync rate is related to the resolution and that 800x600 was at 31khz.

15khz is low res
24khz is med res
31khz is high res

Mikeosoft
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Re: resolution in regards to dual sync 15/24khz

Post by Mikeosoft » April 1st, 2011, 9:19 pm

no that makes total sense, i'm completely mixed up then. I'm sure that soft15hz is enabled and i have it feeding through the jpac which filters all sync other than 15khertz so i'm pretty sure its currently putting out 800 x 600 @ 15khertz @ a windows xp reported 60hertz which according to soft15 app windows xp will say it is at 60 hertz when its really at 15

I dont know and im trying to do some research on the net but the problem is there's very limited info on persons trying to sync CGA monitors in regards to resolution and khertz ratings

fagin
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Re: resolution in regards to dual sync 15/24khz

Post by fagin » April 2nd, 2011, 2:59 pm

Are you not confusing vertical refresh rate with horizontal sync rate?!

Surely the 60hz that windows is reporting is the refresh rate. :)

Mellor
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Re: resolution in regards to dual sync 15/24khz

Post by Mellor » April 3rd, 2011, 8:31 am

No arcade monitor of that era, probably even now, will have a native resolution of 800x600. That is SVGA and is higher than VGA (640x480). In fact if you fed a progressive signal of 800x600 to the Rodotron chassis it would short out the horizontal output transistor and a few other bits within the horizontal circuit!

If you have only installed the 15khz mode of soft 15khz then you will sending an interlaced 800x600 signal to the monitor, that is why you see flicker mainly on white objects. If you had installed 31khz mode as well then it would send a progressive signal that the monitors cannot support. The Rodotron will throw a wobbler with these for sure!

CPS 2 is 15khz and will have a native resolution of 384x224.

SVGA (800x600) is higher than 31khz, more like 35khz I think.

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Chi
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Re: resolution in regards to dual sync 15/24khz

Post by Chi » April 3rd, 2011, 11:38 am

Screen resolution on a monitor which has a fixed horizontal refresh rate is a factor of two main aspects: the number of lines, and the vertical refresh rate (which is also not always very adjustable on these types of monitors).

You will not get any resolution of 640x480 or 800x600 at 50Hz or 60Hz on a 15kHz monitor without flicker. It's simply not possible.

A non-interlaced 800x600 that runs at 31kHz would have to have a refresh rate of about 48Hz.
"TO THE untrained eye Christian Cooper might have been stamping out a small fire " - The Times, 7th Feb, 2004

Mikeosoft
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Re: resolution in regards to dual sync 15/24khz

Post by Mikeosoft » April 24th, 2011, 8:16 am

ok both your comments make sense but don't answer my question. then why will my monitor not catch the signal and sync at 15hz 640x480 when i set that setting in my switchrez? (all i get is non sync'd waves)

edit\\
don't mean to come across sounding rude, just a tad fustrated with my monitor right now. I can repair physical damage but software configuration is the death of me i swear

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grantspain
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Re: resolution in regards to dual sync 15/24khz

Post by grantspain » April 24th, 2011, 10:37 am

all your questions should be answered over on BYOAC forums-there are a mass of posts regarding similar matters

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