Amiga RGB - SCART cable - How to wire it?

[mingle]

Hi,

I have an Samsung SyncMaster 17" LCD monitor/TV which has an (RGB)SCART connector on the back and I'd like to make up a cable to be able to connect my A1200 up to it (via the RGB port)... It's a UK-spec TV, some I'm hoping to get a decent picture via the SCART input...

I did a Google, but came across a number of variations of Amiga-SCART cables...

Just wondered if anyone (who has/had their Amiga connected to an LCD telly using a SCART cable) could tell me the wiring combination that worked for them?

Cheers,

Mike.

[mingle]

Hi Skippy,

Thanks for the info...

Your pics show a few resistors too - including one of the composite-sync (SCART pin-20)... Did you follow the additional instructions in the article you mentioned?:

http://www.jeacle.ie/pub/articles/scart/

Don't suppose you have a nice, clear  diagram of your cable?

Cheers,

Mike.

[mingle]

I'm pretty sure it does support RGB (not sure about the difference 'sync' makes?), as the SCART port is labelled "EXT(RGB)"...

Well, I hope it does!

The model number is 711MP.

Cheers,

Mike.

[mingle]

Hmm...

I tried feeding 12V DC (via a 1amp mains transformer) onto pin 8 and I got an intermittent rolling image, but also a burning smell from inside the TV! So I immediately switched off!

Hopefully I haven't foobarred it up! :-)

There are so many conflicting articles and diagrams and what value resistor (if any) need to be connected to the +12V (pin 22) and +5V (pin 23) before the signals are fed into the SCART connector.

Does anyone know what value resistors I need to add to pin 16 and 8 (of the SCART plug)?

Cheers,

Mike.

[mingle]

Hi Skippy,

The problem is that there are about 4 different cables around (with different combinations of resistors, connections, etc) and there's no guarantee that a commercial cable would work.

I'm fine at making cables up, all I need to know now is what resistor values to use on the 12 & 5V supplies into the SCART connector...

Cheers,

Mike.

[mingle]

Hey skippy,

Just looking at the pics of your cable...

What are the resistor values you're using - particularly on pin 20 of the SCART connector..?

Cheers,

Mike.

[mingle]

@alexh,

I'm still trying to figure out the resistor values and wiring (from skippy's dodgey webcam shots!) with little success...

My TV has a button to select the video source (RF, AV, S-Video, SCART, RGB), so I'm not sure if I'd still need pin 8 wired to 12V?

Also, some diagrams show the 12V on the Amiga RGB port (pin 22) being used to drive pin 8 and pin 16 (through a resistor) on the SCART end, whereas some show the Amiga 5V (pin 23) being used for pin 16 (again, via a resistor) - is one way preferable to another?

Skippy's pics also show a resistor on pin 20 of the SCART plug (composite sync), which is the only instance I've seen of this - all other diagrams only show resistors being used on pin 8 and 16.

I'm stuck at the moment and would appreciate any comments to help with the wiring.

Skippy - if you're reading this - a simple diagram of your cable would be a great help! :-)

Cheers,

Mike.

[mingle]

@twizzle,

Thanks for the info... I managed to contact skippy and he was kind enough to send me a rough schematic and even made a short video to explain things - how helpful can you get!

@alexh,

I know what you mean - the conflicting/confusing resistor values had me scratching my head.

I went with skippy's diagram, which has a 100ohm resistor on pin 16 of the SCART plug (+5v from the Amiga's pin 23) and it also has a 100ohm resistor on the CSYNC pin of the SCART plug (pin 20).

I've just wired up my cable (thanks again skippy!) and it works pretty well, although there is some blurriness and 'ghosting' next to vertical sides of letters, window frames, etc - see the following cropped images:

















Not sure if this is just the result of the image-scaling, something to do with grounds/earth, the extra 100ohm resistor on pin 20 or just par for the course with LCDs?

I've also connected the internal cable shielding at both the Amiga and SCART eds of the cable...

Cheers,

Mike.

[mingle]

@Framiga,

I tried without the resistor on pin 20 and it made no difference... Perhaps it's need for some TVs/monitors?

The cable I'm using is about 1.7m long and is shielded. I'm also using individual grounds for the RGB lines.

@skippy,

Thanks again for the help - I have a working cable now. It's just that I expected the picture to be a bit sharper/clearer. But you're right; it's an old machine on a new screen, so I shouldn't expect perfection! :-)

Cheers,

Mike.