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Main => Monitor/Video Forum => Topic started by: commander on January 31, 2011, 04:22:32 am

Title: Scart TV color problems
Post by: commander on January 31, 2011, 04:22:32 am

I bought a new 21" Keysmart(Brand) Scart CRT TV to replace my old Thomson Scart TV(has major convergence issues). The problem with this new TV seems the Red color is not showing as Red at all but more like Brownish Orange(Red is showing as orange and orange is showing as dark yellow in Nokia Monitor Test). Is this a tube quality thing. Any ideas.

Title: Re: Scart TV color problems
Post by: Blanka on January 31, 2011, 06:00:14 am

What connection do you use (Scart can carry S-video, composite and RGB)?
What broadcast standard is the source and what standard is the TV (PAL/NTSC/SECAM)?

Title: Re: Scart TV color problems
Post by: commander on January 31, 2011, 06:25:24 am

Sorry should have been more clear.
I am using Scart RGB cable running from my Notebook under Win XP using Soft15khz at resolution 640 x 288.
In this case the TV standard does not matter.

Title: Re: Scart TV color problems
Post by: rjpe on January 31, 2011, 06:29:00 am

check the wiring with a multimeter - I had lots of similar problems because of my lack of soldering skills in the very beginning...
nevermind... if it works with another tv it's not a wiring problem...
what cable pattern / pinout are you using?
I started using a most simple pattern (arcadevga cable without resistors).

Now I'm using the one that contains 1x100Ohms + 2x1000 Ohms resistors and the sync and colors improved a lot with Soft15Khz.

Title: Re: Scart TV color problems
Post by: commander on January 31, 2011, 06:35:21 am

I have used this same setup and cable with my other Scart TV with no problems at all (i even tested it with the other TV directly after getting this issue), thats what made me think this problem could be from the TV itself.

I am using a simple pattern with 100 Ohms resistor to bring down the voltage from 5V to about 2V on Pin 16(Blanking).
rjpe what do u use the other resistors for ? could u explain your pinout and how the resistors changed the colors exactly.

Title: Re: Scart TV color problems
Post by: rjpe on February 04, 2011, 02:54:27 pm

This is the pinout I used: http://digilander.libero.it/venturi1975/index.html#A55 (http://digilander.libero.it/venturi1975/index.html#A55)
It doesn't affect the colors, but improves the SYNC, and it might show better colors - it did for me

Title: Re: Scart TV color problems
Post by: apfelanni on February 04, 2011, 05:18:21 pm

it appears some tv chassis are more forgiving with the offspec input level on sync. the dual resistor thing fixed it on 2 of my tvs with weird colors via mamescart and soft 15k .  

Title: Re: Scart TV color problems
Post by: commander on February 06, 2011, 11:20:14 am

Thank you guys this dual resistor scheme has improved things significantly for me.
This scheme seems to improve things for lower grade sets.
Back to more testing.