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Author Topic: SCART RGB Lead problem  (Read 26289 times)

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Offline Stedy

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Re: SCART RGB Lead problem
« on: April 12, 2011, 11:25:19 PM »
@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.
« Last Edit: April 12, 2011, 11:34:46 PM by Stedy »
 

Offline Stedy

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Re: SCART RGB Lead problem
« Reply #1 on: April 13, 2011, 10:40:11 PM »
@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