VGA to BNC on PVM - picture roll

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LordBarker
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VGA to BNC on PVM - picture roll

Post by LordBarker »

As above.
installed CRT Emu Driver 2.0 on my PC, output a 15khz perfectly, however when connected to my monitor via a VGA to BNC cable the picture rolls. I have R,G,B and a Black sync line on the VGA to BNC cable, is this correct or is it missing V sync? Have tried various adjustments in the service menu with no luck. Can anyone tell me which VGA to BNC cables I need?
Cheers
Dochartaigh
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Re: VGA to BNC on PVM - picture roll

Post by Dochartaigh »

Generally speaking CRT Emudriver exports RGBHV output so you would be using the gray and black (that's normal colors at least) for H and V sync. You would need a sync combiner of some sort - most people use an Extron RGB interface. You can also just plug it into the in and out of the sync, or use a y-joiner but that's not the correct way to do it and might damage something long term people say.

BUT...I've read that the newest version of CRT Emudriver can output Csync (combined H and V signal) - don't know if it's only with certian video cards or what. I haven't looked into this much but it's worth some more research because it sounds like that could fix your problem as well.

Also wanted to ask, did the VGA to BNC cable you buy ONLY have the black sync line? I don't know how those work but that might be a problem as well if you can only get it to export RGBHV you would need that 5th BNC most definitely.
LordBarker
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Re: VGA to BNC on PVM - picture roll

Post by LordBarker »

Yup,I'm guessing I need VGA to BNC 5 and using a T adapter to combine the sync lines - d'oh! I'm running a Radeon 5450, I thought the c-sync option was only for Legacy cards, but would trying this damage anything on my monitor?

EDIT: Comp Sync does exactly the same, will try a T-adapter in the week and see what happens. Cheers
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orange808
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Re: VGA to BNC on PVM - picture roll

Post by orange808 »

You need an active Copix, Kramer, or Extron RGB sync box. You can't passively change RGB sync with a cable adapter.
We apologise for the inconvenience
Dochartaigh
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Re: VGA to BNC on PVM - picture roll

Post by Dochartaigh »

LordBarker wrote:will try a T-adapter in the week and see what happens. Cheers
Like I said, and Orange808 just said - you really need a sync combiner box of some sort to merge the sync properly. The t joiner will work as a bandaid just to see if that's the problem, but people say it can hurt things...and ruining a PVM because you don't want to drop $15 on an Extron RGB interface wouldn't be too smart...
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buttersoft
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Re: VGA to BNC on PVM - picture roll

Post by buttersoft »

LordBarker wrote:Yup,I'm guessing I need VGA to BNC 5 and using a T adapter to combine the sync lines - d'oh! I'm running a Radeon 5450, I thought the c-sync option was only for Legacy cards, but would trying this damage anything on my monitor?

EDIT: Comp Sync does exactly the same, will try a T-adapter in the week and see what happens. Cheers
Spoiler
c-sync functionality is only for crt_emudriver beta 12 (12.6) for Radeon HD 2000 series to 7000 series cards. Your card is covered by that driver, so you can give it a go and see. It might interfere with games that need newer drivers though.
TBH I'd expect your card will output c-sync at TTL-level. Ideally you'd be putting a resistor of some sort in the line, or just metering it first. It will work for testing, but no one seems to be able to answer the question of what happens if the buffering fails and you're delivering TTL-level 5V sync to a circuit designed for 0.3V that's now 20+ years old. Obviously it's going to depend on the circuit, but can anyone give examples of potential disaster?

EDIT: Calamity has updated crt_emudriver to get c-sync from newer cards/drivers. That was then, this is now :)
Last edited by buttersoft on Thu Mar 08, 2018 11:36 pm, edited 1 time in total.
LordBarker
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Re: VGA to BNC on PVM - picture roll

Post by LordBarker »

Dochartaigh wrote:
LordBarker wrote:will try a T-adapter in the week and see what happens. Cheers
Like I said, and Orange808 just said - you really need a sync combiner box of some sort to merge the sync properly. The t joiner will work as a bandaid just to see if that's the problem, but people say it can hurt things...and ruining a PVM because you don't want to drop $15 on an Extron RGB interface wouldn't be too smart...
Thanks. Can anyone recommend a specific Extron model? I'm in the UK and it seems like a bit of a minefield.
Would this one be suitable? https://www.ebay.co.uk/itm/Extron-RGB-1 ... Sw1JVaBDAj
And do I simply run the VGA from the PC to the in and then VGA to BNC from the out?
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Syntax
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Re: VGA to BNC on PVM - picture roll

Post by Syntax »

LordBarker
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Re: VGA to BNC on PVM - picture roll

Post by LordBarker »

Ta. I could also get a UMSA, but I'm wondering what would be the correct Extron to pick up?
Cheers
Dochartaigh
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Re: VGA to BNC on PVM - picture roll

Post by Dochartaigh »

That Extron you linked to will merge the sync just fine.
LordBarker
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Re: VGA to BNC on PVM - picture roll

Post by LordBarker »

Dochartaigh wrote:That Extron you linked to will merge the sync just fine.
Thank you. Lead-wise, do I just go VGA from PC to VGA in on this Extron, and then from the front VGA out I use the VGA to BNC 4 lead? Is that correct. Sorry, bit stupid on these, never used one before.
Dochartaigh
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Re: VGA to BNC on PVM - picture roll

Post by Dochartaigh »

LordBarker wrote:
Dochartaigh wrote:That Extron you linked to will merge the sync just fine.
Thank you. Lead-wise, do I just go VGA from PC to VGA in on this Extron, and then from the front VGA out I use the VGA to BNC 4 lead? Is that correct. Sorry, bit stupid on these, never used one before.
You can grab the manual from Extron, but yes, regular VGA cable goes in the input. on the back side are BNC's you can run directly to your BVM. You can output RGBS, RGsB (with a dipswitch change usually), RGBHV (if you were using a computer monitor which didn't have a VGA input - only BNC's), etc.

You might also have to mess with some dipswitches like SERR or ADSP on/off if your screen looks funky in any place (think this model has those options).
LordBarker
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Re: VGA to BNC on PVM - picture roll

Post by LordBarker »

Dochartaigh wrote:
LordBarker wrote:
Dochartaigh wrote:That Extron you linked to will merge the sync just fine.
Thank you. Lead-wise, do I just go VGA from PC to VGA in on this Extron, and then from the front VGA out I use the VGA to BNC 4 lead? Is that correct. Sorry, bit stupid on these, never used one before.
You can grab the manual from Extron, but yes, regular VGA cable goes in the input. on the back side are BNC's you can run directly to your BVM. You can output RGBS, RGsB (with a dipswitch change usually), RGBHV (if you were using a computer monitor which didn't have a VGA input - only BNC's), etc.

You might also have to mess with some dipswitches like SERR or ADSP on/off if your screen looks funky in any place (think this model has those options).
Excellent, much appreciated :)
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Syntax
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Re: VGA to BNC on PVM - picture roll

Post by Syntax »

Does the unit linked clean the sync off green completely or just strip it?
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