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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: tribz on April 09, 2011, 09:31:32 AM
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Got my RGB scart lead today from Amigakit and was looking forward to some nice and clear screen Amiga goodness this morning. Unfortunately, I only get the below. It’s a bad picture I know but basically the screen is really black with lots of interference lines. Occasionally it drifts from being a terrible picture to just being a really bad picture.
I've tried the RGB and AV scart sockets on the LG telly. I'm pretty sure the monitor socket on the amiga's ok as when I bought it, it was demo'd to me connected to a multisync monitor and looked great.
Any ideas?
http://www.datacenta.it/Photo1.jpg
ETA http://www.datacenta.it/Photo2.jpg
Hooked it up to another LCD and get a washed out white picture with something just visible at the top. Think its either the cable or the connector but leaning towards the cable?
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From the pics it looks like your TV is not switching to RGB mode correctly with the signal coming from the Amiga. Sometimes on modern flatscreen TV's there is a menu system that lets you select which kind of signal the Scart sockets on it should expect (ie: Composote, S Video, RGB).... :)
It could also be that the voltage on the Blanking (Scart Pin 16) and AV Select (Scart Pin8 ) pins and could either be missing or not being interpreted correctly by the TV... :(
The cable you bought should have have a connection going to scart pin 16 and this needs > 1 to 3V applied to it for the Blanking Signal otherwise the TV will be trying to display a composite picture...
Pin 8 for the AV/Select should also have +12V on it, to display the Amigas picture correctly in 4:3 Apect ration if your TV is a widescreen version.
Do you have the Brand and Model number of the TV your using...
See here for pinouts Amiga to Scart
http://pinouts.ru/VideoCables/AmigaScart_pinout.shtml
I would think the Cable you bought from AmigaKit should be fully wired but you never know, if you can open the SCART hood and check to see if there are connections made to pins 16 & 8 as if there aren't the TV won't switch to RGB mode and you can end up up with a mixed signal like you seem to have... ;)
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Hiya Franko,
Thanks for that. I've got the hood open on each end. I dont know if this is relevant or not but I cant measure resistance on pin 8 whereas I can on pins 16 & 20.
I've been using this as a guide ...
http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_SCART/amiga_scart.html
I can measure the 75 and 330 ohms on pins 16 & 20 so that looks fine but like I say not the 1k on pin 8. I have to confess, I dont really know what that means and if thats good or bad!!
ETA the TV's are a 32" LG 32LG2100 and a 17" Vistron no name brand.
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How to I measure the voltage on the pins on my meter?
I'm a little wary of shorting something that damages my amiga.
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Pin 20 on the Scart end is used by the Amiga for the composite sync signal (on the TV itself this is usually for composite video) and should be fine... :)
Pin 8 (Scart side) I always just connect up directly to pin 22 on the Amiga (+12v)
Pin 16 (Scart side) again I always just connect up directly to pin 23 on the Amiga (+5v)
I have always made my own cables up and never had the need to put resistors inline on any of the connections and have never had any problems getting them to display a picture. The only time I came across this was with an Amiga I bought on eBay which came with an Amiga To SCART RGB cable it wouldn't switch my TV in the living room to RGB (resulting in pictures much like you posted), when I opened up the hoods and spotted the resistors I removed them and re-soldered the wires up directly and it worked fine after that... :)
It's up to yourself, but if there are resistors inline with pins 16 & 8 I would remove them and solder the wire up directly, in 25 years I've never damaged an Amiga or TV by not having these resistors in the cable... :)
PS: If your not too sure about using your meter to measure the voltage then I would advise against it as you could damage your Amiga if you do it wrong... :eek:
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Thanks Franko,
I've removed those resisters and now get a picture like below ...
http://www.datacenta.it/Photo3.jpg
The horizontal banding isnt really there, thats the camera.
So its a better picture but still some ghosting. Also, its a 4m cable, maybe some signal degredation due to length? I'm thinking I might redo the whole cable. Maybe not today though. The sun is shining and that doesnt happen often :)
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Looking at that pic I'd build me own cable (use good quality OFC shielded cable more expensive but worth it) as you shouldn't be getting that ghost image like that appearing... :)
I've made one before 12 metres long and still got a prefect picture, could still be something to do with the TV though, try and get me the Make and model no and I'll see what I can find out... :)
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Modifying a perfectly good cable based on hear-say in this forum is not a wise thing to do.
Every Scart cable from us has been made to modern LCD TV standards and is fully wired. The cable has been assembled correctly and has been Quality Tested before despatch to customer. We test on a wide range of models and use a widely used schematic.
Forums can be a good source of information sometimes but it is better to consult with your dealer before resorting to modifying the product and jumping to conclusions that there is a fault in the product.
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Modifying a perfectly good cable based on hear-say in this forum is not a wise thing to do.
Every Scart cable from us has been made to modern LCD TV standards and is fully wired. The cable has been assembled correctly and has been Quality Tested before despatch to customer. We test on a wide range of models and use a widely used schematic.
Forums can be a good source of information sometimes but it is better to consult with your dealer before resorting to modifying the product and jumping to conclusions that there is a fault in the product.
Ahem... no one said there was a fault in the product... ;)
I simply suggested that he check the product was fully wired and stated that I thought it would be... :)
It's not "hear-say" it's 25 years of experience making such cables for my own use that I advised him with. Modern LCD TVs can be quite hit and miss when it comes to using an Amiga RGB signal with them (as well as DVD Recorders) and in some cases it take a bit of tinkering to build a cable that suits a particular set... :)
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Modifying a perfectly good cable based on hear-say in this forum is not a wise thing to do.
Every Scart cable from us has been made to modern LCD TV standards and is fully wired. The cable has been assembled correctly and has been Quality Tested before despatch to customer. We test on a wide range of models and use a widely used schematic.
Forums can be a good source of information sometimes but it is better to consult with your dealer before resorting to modifying the product and jumping to conclusions that there is a fault in the product.
Hi Matthew?? I note the US numbers and if so, I didnt buy it from the US.
I dont think anyone has said as such that there is a fault in the cable.
It just doesnt work :-)
I have to take issue with it being a perfectly good cable otherwise it would work :-) I've also tried it on my 40" samsung and I couldnt get a viewable picture on that either. So thats 3 different brand LCD's. Not got a CRT to try it on but I to be honest I bought it for LCD compatibility. Like I put earlier, it might be the DB23 connector amiga side but I've seen that working fine connected to a monitor.
Anyway, I'm happy to cut the ends of and redo it. All part of the amiga fun and games.
Dont take it personally. I'm just getting the benefit of forum experience. Enyoy the sunshine and the rest of your weekend.
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Hi Matthew?? I note the US numbers and if so, I didnt buy it from the US.
I dont think anyone has said as such that there is a fault in the cable.
It just doesnt work :-)
I have to take issue with it being a perfectly good cable otherwise it would work :-) I've also tried it on my 40" samsung and I couldnt get a viewable picture on that either. So thats 3 different brand LCD's. Not got a CRT to try it on but I to be honest I bought it for LCD compatibility. Like I put earlier, it might be the DB23 connector amiga side but I've seen that working fine connected to a monitor.
Anyway, I'm happy to cut the ends of and redo it. All part of the amiga fun and games.
Dont take it personally. I'm just getting the benefit of forum experience. Enyoy the sunshine and the rest of your weekend.
Some LCD scarts dont accept RGB signals at all, only Composite.
If you have more than one scart socket, generally Scart 1 is the only one that will accept RGB.
On my own Samsung, if I used any socket other than Scart 1, I get white screen.
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You could try using the Composite video output as the sync for your RGB. See the Stedy diagram for info.
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You could try using the Composite video output as the sync for your RGB. See the Stedy diagram for info.
Hello Alex,
So which pin should I solder to where instead?
Thanks :)
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Pin 20 on The SCART Connector for Composite & Pin 17 for its Earth/GND.... :)
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So which pin should I solder to where instead?
?? You linked to the diagram!
An RCA plug (which goes in the yellow RCA socket on the rear of the A1200) Wire it to pin 20 & pin 17 (disconnect whatever normally comes from 23-pin) as per the diagram.
(http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_SCART/SCART_cable.png)
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?? You linked to the diagram!
An RCA plug (which goes in the yellow RCA socket on the rear of the A1200) Wire it to pin 20 & pin 17 (disconnect whatever normally comes from 23-pin) as per the diagram.
Yes, but doesnt mean I understand it! :)
Just so I understand it, get a yellow RCA connector and solder it to pins 20 & 17 ... on the scart connector ?
Thanks
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Pin 20 on The SCART Connector for Composite & Pin 18 for its Earth/GND.... :)
Sorry Franko, I'm a bit confused. I know this is probably simple but which pin on the Db23 to which one on the scart?
Thanks :)
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Hi Tribz... :)
To wire up the composite video connector of the Amiga like AlexH is advising you... :)
You need to connect the central wire of the Composite Video Phono cable to PIN 20 on the SCART connector and the outer sheilding/earth wire of the composite video phono cable to PIN 17 of the SCART connector... :)
Hope that's a wee bit more simpler to understand... :)
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Hi Tribz... :)
To wire up the composite video connector of the Amiga like AlexH is advising you... :)
You need to connect the central wire of the Composite Video Phono cable to PIN 20 on the SCART connector and the outer sheilding/earth wire of the composite video phono cable to PIN 17 of the SCART connector... :)
Hope that's a wee bit more simpler to understand... :)
Thanks, much appreciated haha
Ok, I've done that and now at least I get a picture on AV2 but its a composite one
http://www.datacenta.it/Photo4.jpg
On AV1/RGB, its more stable at least but its still quite out.
http://www.datacenta.it/Photo5.jpg
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The problem with SCART connections is that there isn't a firm agreed standard of interfacing between the various consumer electronics manufacturers. I've always disliked SCART connections for this reason. But, SCART is everywhere so we can't get around it, can we.
At this point I think you need to start measuring some voltages on your SCART connections. I can advise you of what pins to measure, and what results to expect, but firstly do you have a decent multimeter you can use? And are you amenable to taking some voltage measurements?
Regarding the in-line resistors, I think these are used as a kind of crude voltage divider. I think they may even be specific to the requirements of an LCD TV's SCART input, but I've never used SCART on an LCD so I'm not too sure about that.
The 1K in-line resistor on the switching pin (pin 8) may be there for current-limiting reasons, so that you're not connecting a 12V output directly to the input of the LCD. Or, if the LCD's switch input pin is designed to trigger on a voltage lower than +12V (as I said, no agreed standards! Arrrgh!) then perhaps it is there to form a crude voltage divider.
Either way, we need to see some voltage on key pins of the cable before we can figure out what's going on.
AH.
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Regarding the "ghosting" effect, can you confirm that there is no connection to pin 19 on the TV-end of the cable, as per the diagram shown a few posts back?
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AV2 SCART socket on a lot of TVs are usually not RGB enabled and that is most likely why your getting a clear (although composite) picture using that socket... :)
AV1 SCART sockets are usually RGB enabled and from the pic you've just posted it looks to me like it's trying to display both a Composite and RGB signal at the same time... :(
Hence the "double" image your getting... :(
That's what the voltages that get applied to pins 16 & 8 on the Scart socket are for, to tell your TV to switch to RGB display mode and not display the Composite picture. It looks like your TV is not switching to RGB mode and instead trying to display a composite and RGB picture at the same time... :(
It could be one of many different reasons for this but most likely it's the voltages going to pins 16 & 8 on the Scart connector that are incorrect and thus your TV is not switching to RGB mode... :(
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Off topic but... Is anyone else having problems with the site being dead slow the past few days and getting "DataBase Errors" showing up... it's driving me nuts... :(
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most likely it's the voltages going to pins 16 & 8 on the Scart connector that are incorrect and thus your TV is not switching to RGB mode... :(
Agreed - this is why I think we need to see some voltage measurements on the cable, if possible. I think the in-line resistors are there for the purpose of presenting the correct mode-switching voltages to the LCD TV.
AH.
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Hi
One of my scart cabels doesn't work correcly with my lcd tv.
Picture is light, I mean that it is hardly visible, it is like a ghost. No dark colours it is like contrast would be 0.
What is wrong with it? Problem can't be TV, it is proven to work with amiga.
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Think I'm there or thereabouts now!
http://www.datacenta.it/Photo6.jpg
I started again and used this http://wiki.classicamiga.com/Amiga_RGB_to_Scart_lead
Would I be right in thinking this isnt 'fully wired'? Picture is miles better than composite with just some ghosting
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AV1 SCART sockets are usually RGB enabled and from the pic you've just posted it looks to me like it's trying to display both a Composite and RGB signal at the same time... :(
Hence the "double" image your getting... :(
That's what the voltages that get applied to pins 16 & 8 on the Scart socket are for, to tell your TV to switch to RGB display mode and not display the Composite picture. It looks like your TV is not switching to RGB mode and instead trying to display a composite and RGB picture at the same time... :(
It could be one of many different reasons for this but most likely it's the voltages going to pins 16 & 8 on the Scart connector that are incorrect and thus your TV is not switching to RGB mode... :(
Interesting, I wonder if disconnecting composite wire will remove the little remaining ghosting. I'll try it now!
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Agreed - this is why I think we need to see some voltage measurements on the cable, if possible. I think the in-line resistors are there for the purpose of presenting the correct mode-switching voltages to the LCD TV.
AH.
I think your right. I've got a meter but I dont really know how to take a reading. I've been a bit wary incase I short something.
I've got no resisters attached in the now working cable.
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Hi
One of my scart cabels doesn't work correcly with my lcd tv.
Picture is light, I mean that it is hardly visible, it is like a ghost. No dark colours it is like contrast would be 0.
What is wrong with it? Problem can't be TV, it is proven to work with amiga.
Is it like this ?
http://www.datacenta.it/Photo2.jpg
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Exactly same
I could try to fix this myself, but I'm not experienced to soldering.
So I would appreciate if I could get good instructions what to try.
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Interesting, I wonder if disconnecting composite wire will remove the little remaining ghosting. I'll try it now!
The remaining ghosting was caused by having the L/R rca being wired at the DB23 end. Must have been some interference. I've connected them in at the SCART end and no ghosting at all now, great picture.
http://www.datacenta.it/Photo7.jpg (phone cam not doing it justice)
Thanks for all the help. This is a milestone day for my miggy. Everything done, time to play.
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Exactly same
I could try to fix this myself, but I'm not experienced to soldering.
So I would appreciate if I could get good instructions what to try.
The thing I've learned this weekend is there are about a gazzilion ways to wire up a scart lead. This is the one that worked for me ...
http://wiki.classicamiga.com/Amiga_RGB_to_Scart_lead
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What did you changed, I would like to do excatly as you did? Did I understand correctly, only 6 wires needed to picture? 3 for audio?
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What did you changed, I would like to do excatly as you did? Did I understand correctly, only 6 wires needed to picture? 3 for audio?
Correct, just like the schematic on that wiki link. I didnt use any resisters on mine.
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The remaining ghosting was caused by having the L/R rca being wired at the DB23 end. Must have been some interference. I've connected them in at the SCART end and no ghosting at all now, great picture.
http://www.datacenta.it/Photo7.jpg (phone cam not doing it justice)
Thanks for all the help. This is a milestone day for my miggy. Everything done, time to play.
Glad you finally got it sorted... :)
So which way worked best for you resistors or no resistors ??? :)
(sorry the sites so slow just now, I've only just spotted your reply... always found myself putting in these resistors cause a lot of problems with LCD/flatscreen TV's... ;))
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Just to be sure, NO resistor for 12v wire? Fron pin 22 to pin 16??
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Just to be sure, NO resistor for 12v wire? Fron pin 22 to pin 16??
It looks like that's what tribz has done, as I say I've found having these resistors on the cable to cause a lot of these problems with flatscreen TVs... :)
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It could also be usefull to know what was wrong with tribz scart cable? How much soldering or maybe just cutting wires?
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From what he's described after following the advice given here, he's simply removed any of the resistors that were in the cable and instead of using the composite sync signal coming from the Amigas 23 PIN Video output, he's spliced in a Phono/RCA cable to use the Amigas Composite Video output for the sync signal instead... :)
(The composite sync signal given out by the Amiga's 23 PIN D-SUB Video output can be very flakey when used with a lot of modern flatscreen TVs and sometimes you have to use the Amigas Phono/RCA Composite Video output instead to get a clean sync signal...:))
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OK
Again just to be sure:
1. Remove resistor from from line 22 -> 16
2. Composite sync is pin 10 in d-sub, move it to pin 20 on scart connector?
That's it??
Argh :( I didn't get it
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From what he's described after following the advice given here, he's simply removed any of the resistors that were in the cable and instead of using the composite sync signal coming from the Amigas 23 PIN Video output, he's spliced in a Phono/RCA cable to use the Amigas Composite Video output for the sync signal instead... :)
Hiya Franko,
The composite phono plug didnt work for me, well it did but it only gave me a composite picture.
I started again using this image with out any resisters. I had a few wires left unused which I presume where all the RGB grounds.
http://wiki.classicamiga.com/Image:Amiga-rgb-to-scart_sc1.jpg
(http://wiki.classicamiga.com/Image:Amiga-rgb-to-scart_sc1.jpg)
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OK
Again just to be sure:
1. Remove resistor from from line 22 -> 16
2. Composite sync is pin 10 in d-sub, move it to pin 20 on scart connector?
That's it??
Argh :( I didn't get it
Dont worry, you'll get there. I found it a bit confusing as well.
One thing to note is that my lead only works in AV1/RGB and not AV2. You are in AV1 on your LCD arent you?
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OK
What I have here connected
http://wiki.classicamiga.com/Amiga_RGB_to_Scart_lead
Scart
5, 7, 9, 11, 13, 15, 17, 18 and 20. 17 and 18 are connected with jumpwire
So need to figure out 5, 9, 13 what those are for / where they go (ground signals???) and cut jumpwire form 17 to 18. Get 12v to pin 16
D-sub is has all needed wires exept 22
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Vesalia has this SCART cable (Amiga RGB -> SCART), stereo, 2m. will it work with LCD TV? Does any one know how this is wired?
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OK
What I have here connected
http://wiki.classicamiga.com/Amiga_RGB_to_Scart_lead
Scart
5, 7, 9, 11, 13, 15, 17, 18 and 20. 17 and 18 are connected with jumpwire
So need to figure out 5, 9, 13 what those are for / where they go (ground signals???) and cut jumpwire form 17 to 18. Get 12v to pin 16
D-sub is has all needed wires exept 22
pins 5-9-13 SCART side are the RGB ground signals thats must go to
pins 16-17-18 Amiga RGB connector side (actually it would be better to have single shielded mini-coaxial cables for R-G-B and CSync)
Keep as reference (resistors apart which your telly doesn't need) Jan's page
http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_SCART/amiga_scart.html
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No I'm confused... wich one is that I need? Those two are totally diffent and my current cable doesn't have needed wire to do later one.
Do I cut those ground wires or not?? "pins 5-9-13 SCART side are the RGB ground signals thats must go to pins 16-17-18 Amiga RGB connector side". And why my cable has jump wire from 17 to 18?? What I do with it?? It is composite video ground and logic ground???
With this one I just need to move one wire to different pin and do some wire cutting
http://wiki.classicamiga.com/Amiga_RGB_to_Scart_lead
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beeing all GND grounds (SCART 5-9-13 and AmigaRGB 16-17-18), yes keep it as they are.
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Does anyone now how those vesalia's cabels are wired? Will they work with LCD tv??
I rather buy new cabel than risk anything trying to make my own.
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AmigaKit's cables are most likely to work with LCDTV.
I think this thread was an example of a broken TV SCART socket design which had grounds incorrectly wired inside the TV. By leaving a few out it got rid of the problem.
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OK I've made some reserch, my cable is othervice identical to this
http://wiki.classicamiga.com/Amiga_RGB_to_Scart_lead
*Except 12v from 22 to 16 my cable doesn't have that.
*I've quite many ground wires connected, 3 video ground to pins 5, 9 and 13
*17/18 composite video ground/logic ground are connected with jumpwire
So my questions are,
*If I modify one of the ground wires to 12v is it ok? From pins 22 to 16??
[edit] I'll remove audio wires and use one of them to get that 12v, so after that I still have 2 wires to use to another purpose. Here http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_SCART/amiga_scart.html pin 16 has said to be rgb mode and it is wired to 23 on d-sub connector?????? SO will I connect pin 16 to 22 or 23???? To pin 22 wire comes from d-sub 8 wich is a switch???
*The is also ground wire soldered to D-Sub connector's shield but no connection to Scart connector shield??? What I do with that? Should I join that wire to scart connector's shield?
I really would appreciate if you could help me with this.
My problem is excatly like this :
http://www.datacenta.it/Photo2.jpg
There is a picture but it is hardly visible.
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@Tribz
Your original problem was caused by an incorrect voltage on pin 16. The Video decoder IC within the TV was using the SCART blanking feature and alpha blending the RGB and composite (derived by the look of it) video signals. That is why you had a ghosted image, the composite video signal was 4-6us ahead of the RGB signal.
I wrote the SCART cable guide and drew the diagram shown in this thread. The resistor from pin 10 of the Amiga (TTL CSYNC) is very important, without it you risk damaging your LCD TV. The Amiga CSYNC output is a HCMOS TTL signal with an Amplitude of >4.5V. The composite video input of the TV expects at most a 1V video signal. The devices typically operate of 3.3/1.8V supplies so the >4.5V signal from the Amiga is not good news.
The Amigakit SCART cables are wired to my diagram. Could you supply the model number of your TV please, would be interested to know why an LCD does not work, this cable has been widely tested.
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@Tribz
Your original problem was caused by an incorrect voltage on pin 8. The Video decoder IC within the TV was using the SCART blanking feature and alpha blending the RGB and composite (derived by the look of it) video signals. That is why you had a ghosted image, the composite video signal was 4-6us ahead of the RGB signal.
I wrote the SCART cable guide and drew the diagram shown in this thread. The resistor from pin 10 of the Amiga (TTL CSYNC) is very important, without it you risk damaging your LCD TV. The Amiga CSYNC output is a HCMOS TTL signal with an Amplitude of >4.5V. The composite video input of the TV expects at most a 1V video signal. The devices typically operate of 3.3/1.8V supplies so the >4.5V signal from the Amiga is not good news.
The Amigakit SCART cables are wired to my diagram. Could you supply the model number of your TV please, would be interested to know why an LCD does not work, this cable has been widely tested.
Stedy would you help me?
What should I do
*
Connect D-Sub 22 to SCART 16
OR
*
Connect D-Sub 22 to SCART 8 and D-Sub 23 to SCART 16
AND
What I do with that ground signal from D-Sub shield? Do I connect it to scar connector shield?
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@utri007
Follow my original cable diagram here:
http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_SCART/amiga_scart.html
So connect D-sub 22 to pin 8 via 1 1K current limiting resistor.
Connect D-sub 23 to pin 16 via a 75 ohm resistor. This should yield a voltage around 2.5V at the SCART socket, thus selecting RGB input. Looks like your TV has selected CVBS/Composite, hence the completely white screen.
Ian
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I ordered scart cable from Amikit, picture quality is PERFECT :) even in hires modes, no flickerin/blur etc.
My last question is: It works only in SCART1, SCART2 doesn't give picture at all. SCART1 is RGB, but is it possible to make cable wich gives picture from SCART2???
I've 3 amigas, wich I wanto to connect to LCD TV
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I ordered scart cable from Amikit, picture quality is PERFECT :) even in hires modes, no flickerin/blur etc.
My last question is: It works only in SCART1, SCART2 doesn't give picture at all. SCART1 is RGB, but is it possible to make cable wich gives picture from SCART2???
I've 3 amigas, wich I wanto to connect to LCD TV
Most TVs only have SCART1 RGB enabled and unfortunately on most TVs SCART2 usually is only hard wired for Composite and SVIDEO... :(
Sometimes on more expensive TV's there is a menu whereby you can switch SCART2 to RGB but this is quite rare and it's usually a case of SCART2 not being hard wired for RGB... ;)
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You could try a SCART switcher: http://www.argos.co.uk/webapp/wcs/stores/servlet/Search?storeId=10001&catalogId=1500002701&langId=-1&searchTerms=SCART+BLOCK