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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: mingle on December 14, 2008, 04:11:15 AM
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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.
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Hi there Mingle, a couple of links and some snapshots.
I use the Samsung SM2032MW with an RGB-SCART cable for my a1200, works a charm.
Pinouts:
http://amigarealm.dtdns.net/amigarealm/resources/pinouts.htm
Scart/RGB Diagram:
http://www.jeacle.ie/pub/articles/scart/
Some dodgy webcam snapshots of my cable:
http://amigarealm.dtdns.net/tmp/scart/
Take care,
Skippy.
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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.
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The only resistors you should need will be on Pin 16 Fast Blanking (aka RGB select) and on Pin 8 (AV Select)
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mingle wrote:
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.
are you sure that your monitor/tv supports analogic RGB+Sync through SCART? mine seems not.
Try to post here the exact model name
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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.
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That "EXT(RGB)" seems a good yes , indeed! :-)
I have here a LG 19LS4R that doesn't works with the STB in RGB mode (looking now at the monitor/tv schematics)
Edit- just for the record ... after looking at the schematics, even my LG supports RGB over SCART.
Everything pointed in a defective SCART cable (red channel wire knackered) :-)
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The resistors are on the correct pins. It's a commercially built RGB SCART cable that I have successfully made replicas of for use on my other Amigas.
If you require any further information, Mingle, just let me know. I do recommend making one of these cables to compliment your LCD's clarity.
Le Skip
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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.
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Well for the price of you not knowing what you're doing and resulting in costly damage to your equipment, I'd strongly recommend you simply purchase the cable for a mere £15.
http://amigakit.leamancomputing.com/catalog/product_info.php?cPath=21_72&products_id=226
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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.
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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.
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I used
1st band: Brown
2nd band: Black
3rd band: Brown
4th band: Gold
SkippyFox
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@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.
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http://www.avishowtech.com/mbhp/res.html
here is the site to find out your resistor values
the 1 that skippy is using is 100hms +/-5%
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It doesn't matter which pin you use (12v or 5v) as long as your resistor value is correct.
To be honest I've never trusted ANY of the resistor values on ANY of the accredited Amiga->SCART diagrams.
Most diagrams recommend connecting pin 8 to 12v via 1K ohm resistor in-series. How on earth that makes a voltage of between 9.5v and 12v I dunno.
Most diagrams recommend connecting pin 6 to 12v via a 150 ohms in-series. How on earth that can make the voltage between 1-3v, especially as it uses a lower resistor value to that above!!
If anything I would have thought the resistor values are the wrong way round!?!
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@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:
(http://rolands50.googlepages.com/ghost1.jpg) (http://rolands50.googlepages.com/ghost2.jpg)
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.
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that 100 ohm resistor to the CSYNC have no sence IMHO.
Secondly, are yours R G B and CSync wires shielded? how long the cable is?
anyway LCD are crap at that low Horizontal frequencies (above all if you have always used CRT in the past)
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I think from a purists point of view you could argue some extremely mild ghosting. But I think you need to keep in mind that the Amiga's RGB is very basic and that you are using an LCD TV as a monitor.
I don't really understand what absolute level of clarity you're hoping to achieve given the combination of equipment. It's not as though you've plugged some Nvidia Geforce effort into a High Def LCD monitor.
You may also experience a "rastering" line effect on motion, IE: mouse movement or scroller.
http://www.lumalaser.com/images/samples/Graphics-RasterGirl-large.jpg
With Amiga RGB to LCD.
Le Bush Kangaroo.
Have any of you other dweebs actually posted any valid schematics or comments? No, simple hypothised theories.
Just posting for the sake of incrementing your babble points counters. - heh. That's gonna go down really well - lol.
:crazy:
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@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.
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Excellent, delivered the facts with no nonsensical drivel unlike the other pretentious postings to this thread.
Praise be to me, thanks to the Lord for blessing me with superior intelligence. :lol:
SkippyFox. 'Real Amiga User' :juggler: