Need some advice regarding connecting VGA to a PVM

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parski
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Need some advice regarding connecting VGA to a PVM

Post by parski »

Hello!

I recently bought a MIMO Genius Box II, a scan converter that lets me input a 31kHz 480p signal and output a 15kHz 240p signal. I want to use this to connect my gaming PC to my PVM. This is the setup so far:

[PC] --VGA-to-VGA--> [GB2] --VGA-to-4-BNC--> [PVM]

Now, the PVM I have is a Sony PVM 20M4E. I've used it up until now with this cable along with this cable built for sync over luma or a Wii RGB SCART cable. They've been working great! However, using the VGA-to-4-BNC cable the image is jumping all over the place. If I disconnect the VGA cable between my PC and the Genius Box the image is still freaking out, so I'm pretty sure it's the cable between the scan converter and the PVM that is the problem.

I'm not very good with sync, but I do realise that RGBHV and RGBs are different sets of letters. I'm pretty sure that VGA outputs the former and that my PVM takes the latter. I'm now also pretty sure that this cable just combines the H and V sync and that my PVM can't figure out what to do.

Could anybody point me in the right direction? I just want it to work. The Genius Box II has a VGA output as well as a much more intimidating looking RGB output. I'm not sure if it has RGBs in that one or if I'm gonna need a sync converter if that is a thing. Maybe I just need another cable. Please let me know!
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Fudoh
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Re: Need some advice regarding connecting VGA to a PVM

Post by Fudoh »

I'm now also pretty sure that this cable just combines the H and V sync and that my PVM can't figure out what to do.
not even that. I just leaves the V-sync pin unconnected.

You can use any of the Extron interfaces ($15 on ebay) to actively convert RGHBV to RGsB or RGBs.

The green MODU-1 connector on the GII might already output RGBs, but if you don't have a proper connector or cable to use with it, the Extron RGB interface is certainly the easier way.
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parski
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Re: Need some advice regarding connecting VGA to a PVM

Post by parski »

Fudoh wrote:
I'm now also pretty sure that this cable just combines the H and V sync and that my PVM can't figure out what to do.
not even that. I just leaves the V-sync pin unconnected.

You can use any of the Extron interfaces ($15 on ebay) to actively convert RGHBV to RGsB or RGBs.

The green MODU-1 connector on the GII might already output RGBs, but if you don't have a proper connector or cable to use with it, the Extron RGB interface is certainly the easier way.
That's a great idea. Do you think a modern looking one like this will work? It has BNC outputs for R G B H V S so I'm guessing I can use the VGA input from the GB2 and output via BNC directly on the RGB and S.

I would also like to thank you for your brilliant write-ups and contributions to this field. They have helped me a LOT and they make my life a lot more fun. It means a lot to me.
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Fudoh
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Re: Need some advice regarding connecting VGA to a PVM

Post by Fudoh »

I'm guessing I can use the VGA input from the GB2 and output via BNC directly on the RGB and S.
should be fine yes. I was using the same setup when I tested the Genius II expect that I was using a RGsB output which just requires 3 BNC cables instead of 4. But your monitor has to be able to accept that (BVM in my case).
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parski
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Re: Need some advice regarding connecting VGA to a PVM

Post by parski »

Fudoh wrote:should be fine yes. I was using the same setup when I tested the Genius II expect that I was using a RGsB output which just requires 3 BNC cables instead of 4. But your monitor has to be able to accept that (BVM in my case).
Thanks! I just bought the one I linked. One last question for now: my local cable retailer has BNC male to male cables listed with an impedance of 75 Ω. They are pretty expensive so before I get four of them I thought I'd ask if I can use them or if I need some terminators or something if I want to use them or if I should get completely different cables.
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Fudoh
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Re: Need some advice regarding connecting VGA to a PVM

Post by Fudoh »

75 ohm BNC are right (50 ohms are for audio), but these shouldn't be expensive. I bought a lot of these. Usually for 1-2 EUR a piece on ebay for the 1m cables. Look at ebay for "BNC RG59"
mvsfan
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Re: Need some advice regarding connecting VGA to a PVM

Post by mvsfan »

why do people want to connect vga to a Pvm. Arent the PVMS 15khz?

wouldnt it be better to just get something like a Dell Dimension 32" Vga Monitor instead?
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DoomsDave
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Re: Need some advice regarding connecting VGA to a PVM

Post by DoomsDave »

mvsfan wrote:why do people want to connect vga to a Pvm. Arent the PVMS 15khz?

wouldnt it be better to just get something like a Dell Dimension 32" Vga Monitor instead?

PVM 20L5 accepts up to 1080i but in OP's case I'm guessing he wants it for something like crt_emudriver or soft15khz.
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parski
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Re: Need some advice regarding connecting VGA to a PVM

Post by parski »

Fudoh wrote:75 ohm BNC are right (50 ohms are for audio), but these shouldn't be expensive. I bought a lot of these. Usually for 1-2 EUR a piece on ebay for the 1m cables. Look at ebay for "BNC RG59"
Thank you so much! You've been very helpful. I really appreciate it.
DoomsDave wrote:
mvsfan wrote:why do people want to connect vga to a Pvm. Arent the PVMS 15khz?

wouldnt it be better to just get something like a Dell Dimension 32" Vga Monitor instead?

PVM 20L5 accepts up to 1080i but in OP's case I'm guessing he wants it for something like crt_emudriver or soft15khz.
I'm not capable of soldering my consoles to add RGB output support so I've decided to emulate on my PC and output the video to my PVM. It's been quite the dilemma to choose between committing fully to original hardware or to go the emulation route but I've settled for the latter. Emulation is accurate enough for me to make the switch and I'm very eager to get my setup up and running.
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ApolloBoy
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Re: Need some advice regarding connecting VGA to a PVM

Post by ApolloBoy »

parski wrote: I'm not capable of soldering my consoles to add RGB output support
Depending on what consoles you have, you actually don't have to do any kind of modifications. Most consoles past the 8-bit era output RGB straight out of the box and all you need are just the proper cables.
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parski
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Re: Need some advice regarding connecting VGA to a PVM

Post by parski »

ApolloBoy wrote:
parski wrote: I'm not capable of soldering my consoles to add RGB output support
Depending on what consoles you have, you actually don't have to do any kind of modifications. Most consoles past the 8-bit era output RGB straight out of the box and all you need are just the proper cables.
I'm aware. I have RGB cables for the my consoles that support it out of the box but the composite output on Super Nintendo Jr makes my eyes bleed in comparison and the price point of the games I'm missing are putting me off. I'd rather just emulate at this point. I've also considered the everdrive route but doing everything on a PC makes it a lot more accessible to me.

I'm still awaiting the RGB interface by the way. It should arrive any day now.
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