Help with Dreamcast/PVM/OSSC/GDEMU

The place for all discussion on gaming hardware
Post Reply
Gnomenthusiast
Posts: 66
Joined: Tue Nov 15, 2016 6:22 am

Help with Dreamcast/PVM/OSSC/GDEMU

Post by Gnomenthusiast »

Hi, just looking for some help and advice, I've hooked up most of my other consoles (PS1, MegaDrive, NES (RGB MOD), SNES, N64 (RGB MOD)) with no problems.

Recently someone gave me a Dreamcast, I hooked it up to my PVM20M4E with an RGB Scart Cable and the normal SCART -> 5x BNC cable and it booted and the menu system was shown on screen.

Games wouldn't boot, so I replaced the GD-Drive with a GDEMU Unit.

After the GDEMU installation, the DC system menu would load, I would hit play and GDMENU system would launch (confirmed by the SEGA splash screen and GDMENU on the controller screen)
but after the splash no menu would appear on the screen of the PVM.

I plugged the RGB Scart cable into the OSSC input, and the OSSC output to a monitor, and the GDMENU is definitely loading (and I was able to launch a game).

Why won't the GDMENU or Games show on the PVM, when the DC Menu does?

I get the feeling I'm doing something silly, but I can't figure out what, and the DC menu doesn't seem to have many options.

Thanks in advance,

GE
User avatar
Kez
Posts: 840
Joined: Thu Jul 20, 2017 7:09 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Kez »

May be worth taking a look at what the OSSC has to say about the input signal once it goes into GDMENU.

Seems like a bit of a stretch as you are using a SCART cable but if your DC started outputting 480p then your PVM would not display it.
Gnomenthusiast
Posts: 66
Joined: Tue Nov 15, 2016 6:22 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Gnomenthusiast »

Kez wrote:May be worth taking a look at what the OSSC has to say about the input signal once it goes into GDMENU.

Seems like a bit of a stretch as you are using a SCART cable but if your DC started outputting 480p then your PVM would not display it.
This is what I thought, but it doesn't look like you have a choice between 480i/p (you are correct my PVM does i but not p).

Tonight I will try deleting the GDMENU and just getting it to load a game directly (instead of loading the menu).

Thanks
User avatar
LDigital
Posts: 398
Joined: Sun Jan 17, 2016 9:15 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by LDigital »

Gdmenu works ok on my ossc but I have mine connected via vga
Gnomenthusiast
Posts: 66
Joined: Tue Nov 15, 2016 6:22 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Gnomenthusiast »

LDigital wrote:Gdmenu works ok on my ossc but I have mine connected via vga
This is what I want to do, but beharbros aren't selling any boxes at the moment.

GDMenu works on the OSSC for me too, but my monitor doesn't handle the signal well and I don't have my projector set up at the moment.
User avatar
Kez
Posts: 840
Joined: Thu Jul 20, 2017 7:09 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Kez »

Gnomenthusiast wrote:This is what I thought, but it doesn't look like you have a choice between 480i/p (you are correct my PVM does i but not p).

Tonight I will try deleting the GDMENU and just getting it to load a game directly (instead of loading the menu).

Thanks
Yeah IIRC under normal circumstances the 480p is triggered by the VGA box grounding some pins on the connector, but I was wondering if GDMENU overrides that somehow.

The OSSC should have a status display that tells you about the incoming signal, so I think it would be worthwhile to see what it says during the system menu and whether it changes when entering GDMENU.
Gnomenthusiast
Posts: 66
Joined: Tue Nov 15, 2016 6:22 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Gnomenthusiast »

Kez wrote:
Gnomenthusiast wrote:This is what I thought, but it doesn't look like you have a choice between 480i/p (you are correct my PVM does i but not p).

Tonight I will try deleting the GDMENU and just getting it to load a game directly (instead of loading the menu).

Thanks
Yeah IIRC under normal circumstances the 480p is triggered by the VGA box grounding some pins on the connector, but I was wondering if GDMENU overrides that somehow.

The OSSC should have a status display that tells you about the incoming signal, so I think it would be worthwhile to see what it says during the system menu and whether it changes when entering GDMENU.
OK, Good plan, I will test with a game and use the OSSC to see what's going on when GDMenu boots.

Thanks guys I will report back later.
User avatar
citrus3000psi
Posts: 668
Joined: Wed Dec 25, 2013 11:56 pm
Location: Indiana

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by citrus3000psi »

I have a USB-GDROM, its also picky

480i Composite - Works fine
480i RGB - Works fine
15Khz VGA - Black Screen
31Khz VGA - Works fine
Gnomenthusiast
Posts: 66
Joined: Tue Nov 15, 2016 6:22 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Gnomenthusiast »

citrus3000psi wrote:I have a USB-GDROM, its also picky

480i Composite - Works fine
480i RGB - Works fine
15Khz VGA - Black Screen
31Khz VGA - Works fine
Interesting. I'm hoping there's no 15khz problems with VGA on the GDEMU.

Is there a test program like the 240p suite for DC?
User avatar
Kez
Posts: 840
Joined: Thu Jul 20, 2017 7:09 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Kez »

Gnomenthusiast wrote:Is there a test program like the 240p suite for DC?
Yes, the 240p test suite :P
Gnomenthusiast
Posts: 66
Joined: Tue Nov 15, 2016 6:22 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Gnomenthusiast »

Kez wrote:
Gnomenthusiast wrote:Is there a test program like the 240p suite for DC?
Yes, the 240p test suite :P

I had no idea, I thought it was only available on the "older" consoles (MegaDrive, Snes, Nes etc).

I will try this too, it looks like it automatically puts out 240p for the graphics with the other modes as test options so it will be perfect!

Thanks!
CobraKing
Posts: 166
Joined: Thu Mar 31, 2016 4:07 pm

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by CobraKing »

OP, there are some games that aren't RGB compatible and some that won't work with the VGA box.

I use the Toro's VGA output from www.beharbros.com to my OSSC then to my HDTV. It can also output RGB via SCART.

Try testing the DC with Composite or S-Video to ensure that it is indeed able to display the games correctly.
User avatar
citrus3000psi
Posts: 668
Joined: Wed Dec 25, 2013 11:56 pm
Location: Indiana

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by citrus3000psi »

Gnomenthusiast wrote:
citrus3000psi wrote:I have a USB-GDROM, its also picky

480i Composite - Works fine
480i RGB - Works fine
15Khz VGA - Black Screen
31Khz VGA - Works fine
Interesting. I'm hoping there's no 15khz problems with VGA on the GDEMU.

Is there a test program like the 240p suite for DC?
I was able to boot up in 31khz, and then after making my selection in the USB-GDROM; flip switch on my vga box to go 15Khz.
Gnomenthusiast
Posts: 66
Joined: Tue Nov 15, 2016 6:22 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Gnomenthusiast »

Update - :

The problem seems to be the GDMENU system, the GDEMU itself works fine if you get rid of the menu and play the games directly.

The menu must be displaying at 480p instead of i, and that can't be displayed on my PVM, but works with the OSSC (but my monitor sucks).

Hopefully Toro boxes will be available again soon and that will allow me to get everything working correctly, but for now changing games with the PCB button isn't too much hassle.
User avatar
citrus3000psi
Posts: 668
Joined: Wed Dec 25, 2013 11:56 pm
Location: Indiana

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by citrus3000psi »

Gnomenthusiast wrote:Update - :

The problem seems to be the GDMENU system, the GDEMU itself works fine if you get rid of the menu and play the games directly.

The menu must be displaying at 480p instead of i, and that can't be displayed on my PVM, but works with the OSSC (but my monitor sucks).

Hopefully Toro boxes will be available again soon and that will allow me to get everything working correctly, but for now changing games with the PCB button isn't too much hassle.
I don't use a toro. I have this box (had it for over 15 years now)

http://www.ebay.com/itm/VGA-Box-by-Naki ... Sw2hNZqpq4

I just recently opened it up, cut pin 6 (blue wire) and wired the wire through and ON-OFF switch.
Gnomenthusiast
Posts: 66
Joined: Tue Nov 15, 2016 6:22 am

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by Gnomenthusiast »

Thanks for your help folks,

It looks like my PVM is having problems, which may have added to making it difficult to finding what was up.

Got the GDMENU and Games working well on a TFT monitor, and the TORO boxes went on sale again at the weekend so I should have one soon.

I should just run the cables for my projector and forget about the PVM, think it's on it's way out.


Cheers
User avatar
BuckoA51
Posts: 3424
Joined: Sat Oct 02, 2010 10:08 am
Location: Ireland
Contact:

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by BuckoA51 »

I have a USB-GDROM, its also picky

480i Composite - Works fine
480i RGB - Works fine
15Khz VGA - Black Screen
31Khz VGA - Works fine
Weird, mine works just fine in 15khz VGA/D-Sub15 mode.
OSSC Forums - http://www.videogameperfection.com/forums
Please check the Wiki before posting about Morph, OSSC, XRGB Mini or XRGB3 - http://junkerhq.net/xrgb/index.php/Main_Page
User avatar
citrus3000psi
Posts: 668
Joined: Wed Dec 25, 2013 11:56 pm
Location: Indiana

Re: Help with Dreamcast/PVM/OSSC/GDEMU

Post by citrus3000psi »

BuckoA51 wrote:
Weird, mine works just fine in 15khz VGA/D-Sub15 mode.

What hardware and firmware version do you have?
Post Reply