Nanao-MS2933 won't sync to 31kHz?

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Sobriquet
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Nanao-MS2933 won't sync to 31kHz?

Post by Sobriquet »

Historically I had an Astro with an MS-9, and a 15kHz setup (PCBs and ArcadeVGA). I shifted the setup over into the Blast a couple of years ago and all is well at 15kHz.
Recently, I've been trying to 31kHz going though too. I've reinstalled the ArcadeVGA 3000 drivers, and told it I have a tri-sync - so now Windows looks to be 31kHz rather than 15kHz interlaced.

I've been trying to get the screen/chassis to sync in 640x480 and it just won't. It seems to be stuck in 15kHz (the OSD, when visible indicates the freq with a 15/24/31 after the name of the adjustment screen).
There's nothing in even the Factory mode to try and override the frequency.

Various things I've tried:
* AVGA 3000 (VGA), JAMMA via J-PAC, 15kHZ (+31kHZ jumper = line-divide split-screen mode) - this is okay during boot/bios, although I get the split screen in Windows
* AVGA 3000 (VGA), JAMMA via J-PAC, 31kHz jumper - won't sync. Can't even see the OSD. Clearly at wrong freq as scrolling horizontally and vertically like mad, if anything can be made out.
* AVGA 3000 (VGA), DE-15 port on monitor (i.e. composite sync)). Ditto.
* Onboard Geforce card, DE-15 port on monitor. I had thought this used to work once upon a time, but no luck now.

I'm obviously a bit worried that if I leave it at the wrong freq and it won't sync for long, that something horrible will happen to it. Any ideas?
I don't really have any 24/31kHz PCBs. Although I have a Naomi I haven't got around to figuring out how to wire up.
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Re: Nanao-MS2933 won't sync to 31kHz?

Post by phillv85 »

It'd be worth testing the NAOMI in 31khz mode to see if that syncs. Have you got a JVS I/O?
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Re: Nanao-MS2933 won't sync to 31kHz?

Post by Sobriquet »

No, don't think I have a JVS I/O. Looks like I would need one. Doh.

I tried one more thing:
* On-board Ge-force -> J-PAC set at 31kHz.
This works. The bios displays, as does the Windows boot sequence. Once it gets into Windows proper it's scrambled.
I'm guessing this is the work of the AVGA drivers though (even though it's not even an ATi card). When I get another chance I'll try forcing XP into VGA mode.
Edit: I Used Safemode (not VGA mode), and that displayed fine at 640x480, so it was the Vga.sys from the ATi/AVGA driver messing that up.

Based on this, I guess going via the DE-15/DSUB is a no-go (For Model-3 or similar rather than VGA I guess). The magic Composite -> Horizontal/Vertical sync the AVGA does must be needed, even though the levels etc. look okay so far as I can tell.
What I don't get is why I can't get 31kHz from the AVGA, via a J-PAC to work. The setup's a bit antiquated, I got it all 6 years back, but it was good enough back then!

I have another ATi care (an HD 4350, which I'd planned to use with CRT_EmuDriver/previously soft15kHz), but that's either a lemon, or the DVI->VGA adapter port isn't being used as the default, no EDID etc. I'll have to plug something into the HDMI port and see if it's alive.
On the plus side, at least the auto-switching circuitry is proven to not be toast!

So many tests to do, so little time!
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Re: Nanao-MS2933 won't sync to 31kHz?

Post by Sobriquet »

Alright, so last post on this - it's as much about Video Cards, Drivers as it is about Monitors + Chassis' at this point.
I had a chance to try a few more things.

The AVGA actually does display 640x480@31kHz if I let it boot all the way into Windows when reconfigured with the 'trisync.exe' utility to the Multisync mode.

Here's my conclusions:
* ArcadeVGA 3000 outputs at 15kHz during BIOS and Windows boot. No way I Can see to change this. This isn't actually relying on the J-PACs line-frequency halving (this was confusing me as to how it was displaying a stable picture and not two)
* J-PAC doesn't have a jumper setting that allows for multi-sync, with the Hori/Vert sync ->Composite sync (though is there some hack I can do where I just short these together?). What I really want is to allow 15/24/31kHz thorough (though cutoff if >31kHz, but to do the other magic with levels and sync).
* I can't use the DE-15 DSUB conector on the monitor (except, perhaps with a mod like the above for composite sync)
* I have to pick 15kHz, or 31kHz. I have three options:
** On-board Geforce, with AVGA removed, JPAC at 31kHz, plus uninstall AVGA drivers = 31kHz Windows + Boot sequence.
** AVGA, JPAC at 31kHz, with AVGA drivers set to multi-sync = can't see boot sequence, but Windows works. 15kHz modes are present though and no way for me to use them because I can't have the J-PAC allow 15 or 31kHz through in any given configuration.
** AVGA, JPAC at 15kHz (plus 31kHz vert halving) = 15kHz interlaced Windows@640x480 +15kHz goodness
Sadly - switching between these configs is a PITA. Jumpers, software, cables AND removing PCIe cards

Unless I'm massively off-base, the real problem here is the J-PAC. If I could make a circuit (or just mod the VGA cable) that output a composite sync which I can connect to the DSUB, I should be able to get 15/24/31kHz out of the AVGA and switching on-the-fly. Something like http://www.epanorama.net/circuits/vga2rgbs.html

This: http://www.ebay.ie/itm/HD15-VGA-Monitor ... 5aef1515e6
Looks pretty handy, DIPs to control the sync modes (Composite, Sync-on-green etc.). Then just need to rewire a 15-pin DSUB instead of the 'HD' connector.
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Re: Nanao-MS2933 won't sync to 31kHz?

Post by Sobriquet »

A happy ending.

So in the end, connecting h/vsync together (i.e. negative composite sync), and removing all the jumpers from the I-PAC did it!
15kHz/31kHz hot switching via JAMMA.

Now I just need to find a hackable cable, since bridging the pins with solder isn't exactly robust :)
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Re: Nanao-MS2933 won't sync to 31kHz?

Post by Sobriquet »

Joined together the relevant pins on the bottom of the J-PAC PCB on the VGA header and that works too as you'd expect.
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