Can you help me set up a BVM monitor?

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Huggers
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Can you help me set up a BVM monitor?

Post by Huggers »

Hi guys. New to the boards. Just got a rather nice BVM but am having a little trouble. I connected up a scart to bnc cable (with sync) into the back of it like so (http://abload.de/img/20141213_1633457zu2a.jpg) and yet I can't get anything out of the screen. I set the channel to RGB but still nothing. What am I doing wrong? Go easy on a newbie!
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Fudoh
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

Scart to BNC cables have a dedicated direction, so make sure yours is wired to go FROM Scart TO BNC.

And in the menu you have enable EXTERNAL SYNC. The standard is internal sync, which is used for component and RGsB.
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Huggers
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Re: Can you help me set up a BVM monitor?

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Fudoh wrote:Scart to BNC cables have a dedicated direction, so make sure yours is wired to go FROM Scart TO BNC.

And in the menu you have enable EXTERNAL SYNC. The standard is internal sync, which is used for component and RGsB.
The cable I'm using is; http://www.retrogamingcables.co.uk/fema ... itors.html

Does this seem correct?
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Fudoh
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

On a BVM you don't need the sync stripper. Since your cable has one, you have to make sure that your source is able to power the LM1881 properly by providing a stable +5V output on the proper pin.
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

If pin 8 is not getting 5 volts, will it mean no picture regardless of whether I need the sync or not?
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Fudoh
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

yes, the LM1881 won't pass any signal without getting proper power.
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Thanks very much Fudoh. Seems I need to grab myself a different cable. So annoying, I want to see this thing in action!
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

It's very easy to bypass the IC. Probably easier than buying a new cable.
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:It's very easy to bypass the IC. Probably easier than buying a new cable.
How do I do this?
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

The circuit has two inputs (signal + 5V) and one output. You just have to connect the input and output directly. Just have a look at it. Should be really easy.
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:The circuit has two inputs (signal + 5V) and one output. You just have to connect the input and output directly. Just have a look at it. Should be really easy.
This is how it looks;

http://abload.de/img/20141213_205611bzy2d.jpg

which wires to which?
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

After some messing around, I got the thing working through component inputs out of my Wii going directly into the monitor via bnc/phono adapters. The picture is INSANE. So bright and crisp.

Still haven't got RGB working as yet. I get a good picture but the colours are all over the place, bright purple or at times bright red covers the whole screen. Any suggestions for me?
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

Still haven't got RGB working as yet. I get a good picture but the colours are all over the place, bright purple or at times bright red covers the whole screen. Any suggestions for me?
this would usually mean that the input is still set the YPbPr instead of RGB. You switched it in the menu along with the int/ext. sync switch ?
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:
Still haven't got RGB working as yet. I get a good picture but the colours are all over the place, bright purple or at times bright red covers the whole screen. Any suggestions for me?
this would usually mean that the input is still set the YPbPr instead of RGB. You switched it in the menu along with the int/ext. sync switch ?
Yes I switched it and the image is so close to be correct. Just way too dark and slightly skewed. It also flickers intermittently.

If I switch the Sync from INT to EXT I lose the picture completely
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

you *HAVE* to use ext. sync for RGB sources. If it doesn't work, then your cable doesn't properly pass sync (yet). Did you bypass the LM1881 ??
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:you *HAVE* to use ext. sync for RGB sources. If it doesn't work, then your cable doesn't properly pass sync (yet). Did you bypass the LM1881 ??
Yeah I removed the chip. Was this a mistake?
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

No, it certainly wasn't. Can you post a picture of what you did ? Does the sync signal connect to pin 20 of the female scart connector ?
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:No, it certainly wasn't. Can you post a picture of what you did ? Does the sync signal connect to pin 20 of the female scart connector ?
I can't right now as I'm not with it but I'll take a photo or two in the morning. Thanks very much for all your help dude
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:No, it certainly wasn't. Can you post a picture of what you did ? Does the sync signal connect to pin 20 of the female scart connector ?
right mate. I have pin 20 connected to sync I believe. Here's some pics, not sure how clear they'll be

http://abload.de/img/20141215_212555u0si9.jpg

http://abload.de/img/20141215_212610pss8o.jpg

http://abload.de/img/20141215_21263446snf.jpg
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

I can't tell, but on the last pic it looks like you're running a ground line to pin 20 and not the sync signal.
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:I can't tell, but on the last pic it looks like you're running a ground line to pin 20 and not the sync signal.
I think that must just be the pic. Pin 20 is connected to the yellow sync cable.
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Hey Fudoh. Got it working like a dream with the Snes and Mega Drive. It looks phenomenal. The only issue I now have is the Saturn will only output a yellow picture and also the Nes through phono to BNC gives me nothing. Apparently I need a specific adapter card for this? Btw, thanks for all your help, I wouldn't have got it working without you

Edit. The Nes outputs a green image
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

And you Saturn is connected through RGB ? If not, get a RGB cable. Shouldn't be any different from your Mega Drive, both in quality and type of connection.

If you only got the stock connection board, then you don't have a composite video decoder. You would need an extension board like the 20D or 21D to use composite. But if the NES is your only composite source, then you should spend the money on a RGB mod for the NES instead and just forget about composite on the BVM.
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:And you Saturn is connected through RGB ? If not, get a RGB cable. Shouldn't be any different from your Mega Drive, both in quality and type of connection.

If you only got the stock connection board, then you don't have a composite video decoder. You would need an extension board like the 20D or 21D to use composite. But if the NES is your only composite source, then you should spend the money on a RGB mod for the NES instead and just forget about composite on the BVM.
http://www.ebay.co.uk/itm/221569634222 is the cable I have for my Saturn. Perhaps it's not up to scratch?

Thought as much about the NES. RGB mod it is
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

Fudoh wrote:And you Saturn is connected through RGB ? If not, get a RGB cable. Shouldn't be any different from your Mega Drive, both in quality and type of connection.

If you only got the stock connection board, then you don't have a composite video decoder. You would need an extension board like the 20D or 21D to use composite. But if the NES is your only composite source, then you should spend the money on a RGB mod for the NES instead and just forget about composite on the BVM.
So I plugged in a 20D extension board and plugged in my Nes through composite. It won't work and in the menu the option for composite isn't selectable. Is this board no good for composite after all?
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Re: Can you help me set up a BVM monitor?

Post by Fudoh »

I don't have access to my PDFs right now. Try to find the manual. There's a list of all extension boards and it shows which boards have onboard decoders and which don't.
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Re: Can you help me set up a BVM monitor?

Post by mickcris »

The 20D does not have a decoder in it. See page 44 of the following pdf to see what does what:

http://www.broadcaststore.com/pdf/model ... manual.pdf

assuming you are needing a PAL decoder, you would need a 21D, 25P, or 27T
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Huggers
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Re: Can you help me set up a BVM monitor?

Post by Huggers »

mickcris wrote:The 20D does not have a decoder in it. See page 44 of the following pdf to see what does what:

http://www.broadcaststore.com/pdf/model ... manual.pdf

assuming you are needing a PAL decoder, you would need a 21D, 25P, or 27T
Hey man thanks for that. Extremely helpful. Now just to track one of those down!
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