15khz PC connected to Bang & Olufsen TV

[Beaps]

Hi all

Can anyone help me out please.

I have a PC running in 15khz mode and running grooveymame. I have made up a VGA to RGB scart cable and it works a treat on a Trinitron and other TVs but nothing on the B&O. Has anyone got any ideas to get it working on a B&O

Ta

[kamiboy]

Does your cable do proper combining of TTL H&V sync into TV level composite sync?

I think B&O's are a bit fussy about being fed proper sync.

[Beaps]

I combined the H&V myself

[viletim]

I combined the H&V myself

Don't just join the wires together, it doesn't make a valid signal.

This works fairly well. Diode D4 can be omitted.

[Beaps]

All looks a little confusing.

- Where did you get the 12v from
- does the vert & horizontal connect using the 330 resister
- Where does the vert connect to in the end


Also thanks for your help.

[gray117]

It's not just because you don't have a blanking signal?

Most trinitrons can be switched and stay in rgb mode manually without one, but not all, and perhaps not your B&O.

Don't suppose you've tried another source without a blanking signal or your B&O? e.g. a supergun

Plenty of people try faking one for sets that require a blanking signal using various methods, got a little setup myself where I tap the blanking and ground (pins 16 and 18 I think) from an old dvd player and tap it into a simple scart switch/extender - the kind that just lets through both inputs - thus combining the blanking signal from the dvd player with one of my superguns.

[kamiboy]

B&O's do at the very least need 3~5v on pin 16 to force them into RGB mode.

[Beaps]

Sorted now, added 5v and works a treat, thanks guys

[viletim]

B&O's do at the very least need 3~5v on pin 16 to force them into RGB mode.

Sorted now, added 5v and works a treat, thanks guys

The range is 1-3 V. If you just connect 5V directly the termination resistor will eventually burn out. Instead, the usual way to drive this pin is to connect 5V through a resistor - something between 100 and 180 ohms will do.

[kamiboy]

That is correct, but doing things the proper way is such a rare occurrence when it comes to the SCART standard. Most console cables that I've seen feed 5v directly to that pin. I really should add that resistor myself, alas I cannot be arsed.

[viletim]

That is correct, but doing things the proper way is such a rare occurrence when it comes to the SCART standard.

Not true. Discounting some Ebay junk (because this is a dumping ground for faulty merchandise), SCART cables and equipment is generally fine. Where have you bought a SCART cable that has 5V wired to the blanking pin?

Connecting 5V to the blanking input is as dangerous as connecting 5V to the video input. It's a 75 ohm input just the same. It is well outside the allowed range and can easily burn the termination resistor which is usually only rated for 125mW or 250mW.

[kamiboy]

The TV's that I play on must be of a superior build because i have been feeding them 5v for years from all my consoles. My cables come from here and there, mostly custom jobs or third party.

Then again the TV's I play on are all B&O's, which I hope are of superior build quality, given their astronomic original retail price.

[bluetrain]

Hello fellow gamers! I kindly ask of assistance.

I also have a B & O trying to connect to groovy mame (15khz) but only get a wobbly picture. I have bought the UMSA connector and thought that would be plug and play but perhaps that is not the case?

[syboxez]

Is it safe to simply combine V and H into one wire if the equipment supports sync levels from .5Vpp all the way to 10Vpp? I'm talking about an Extron Crosspoint in this particular case, which outputs 4-5Vpp sync regardless of input.