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hello,

I own a sms 2 and decided to give it av + rgb mod, i followed the attached schematic, the status as follows:

at first i didn't use any resistors at all just the 220uf caps, for the audio it works, quite low but works.

av mod (yellow) taken from pun 20, it works, i tried it directly to my led television and tried through a hdmi upscaler, it sometimes gives acceptable pic on just av direct, however sometimes the picture goes as if it became partially shadow with some lines, and by removing the cable and reputting it it comes back, but with a little washed out colors, faded, over saturated colors, and through hdmi upscaler its faded and over saturated (in sonic for example sonic is quite sky blue and overall slightly darker than what it should look like), i tried a 330uf cap, picture is somewhat different maybe clearer but not up to expectations.

for the rgb mod, referring to the attached schematic of the sony chip, and since scart cables are not common over here, we use the 5 cables component cable (red , green , blue ,and white+red for audio), so i used 3 more av sockets, gave the first a connection with 220uf cap from pin 23 to work as red, same for green and blue from pins 22 and 21, but no picture at all , nothing no even instantaneous shadow, why?

appreciate your help in advance.

20180404_170124.jpg (275.58 KB)

You fed RGB into component input which is not going to work as they're two separate things (RGB is not YPbPr). RGB uses 4 signals to transfer image so there would need to be 6 connectors with audio - Red, Green, Blue, Sync/CVBS and two audo lines.

The video output is poor looking due to extra circuitry to make the video signal work with RF modulator. Disconnect R21 or C38 and the image should clear up (but you will lose RF support).

thanks a lot for your useful reply, so what would the wires be for YPbPr? is it possible on sms 2?

thnx

You'd need a transcoder for that, there are RGB to component ones on ebay though they give mixed results, you'll have to do some research on the matter.

much appreciated, thnx , i will disconnect r 21 for now and retest the av .

update: disconnected R21 , nothing improved, and worse display goes black after 2 mins, i will replace the cap and add the resistor before it and c

Author	Message
somacast Joined: 08 Apr 2018 Posts: 4	sms 2 : av mod + rgb mod help please Posted: Sun Apr 08, 2018 8:15 am
somacast Joined: 08 Apr 2018 Posts: 4	hello, I own a sms 2 and decided to give it av + rgb mod, i followed the attached schematic, the status as follows: at first i didn't use any resistors at all just the 220uf caps, for the audio it works, quite low but works. av mod (yellow) taken from pun 20, it works, i tried it directly to my led television and tried through a hdmi upscaler, it sometimes gives acceptable pic on just av direct, however sometimes the picture goes as if it became partially shadow with some lines, and by removing the cable and reputting it it comes back, but with a little washed out colors, faded, over saturated colors, and through hdmi upscaler its faded and over saturated (in sonic for example sonic is quite sky blue and overall slightly darker than what it should look like), i tried a 330uf cap, picture is somewhat different maybe clearer but not up to expectations. for the rgb mod, referring to the attached schematic of the sony chip, and since scart cables are not common over here, we use the 5 cables component cable (red , green , blue ,and white+red for audio), so i used 3 more av sockets, gave the first a connection with 220uf cap from pin 23 to work as red, same for green and blue from pins 22 and 21, but no picture at all , nothing no even instantaneous shadow, why? appreciate your help in advance. 20180404_170124.jpg (275.58 KB)

TmEE Joined: 31 Oct 2007 Posts: 853 Location: Estonia, Rapla city	Posted: Sun Apr 08, 2018 11:10 am
	You fed RGB into component input which is not going to work as they're two separate things (RGB is not YPbPr). RGB uses 4 signals to transfer image so there would need to be 6 connectors with audio - Red, Green, Blue, Sync/CVBS and two audo lines. The video output is poor looking due to extra circuitry to make the video signal work with RF modulator. Disconnect R21 or C38 and the image should clear up (but you will lose RF support).

somacast Joined: 08 Apr 2018 Posts: 4	Posted: Sun Apr 08, 2018 12:54 pm
somacast Joined: 08 Apr 2018 Posts: 4	thanks a lot for your useful reply, so what would the wires be for YPbPr? is it possible on sms 2? thnx

TmEE Joined: 31 Oct 2007 Posts: 853 Location: Estonia, Rapla city	Posted: Sun Apr 08, 2018 1:00 pm
	You'd need a transcoder for that, there are RGB to component ones on ebay though they give mixed results, you'll have to do some research on the matter.

somacast Joined: 08 Apr 2018 Posts: 4	Posted: Sun Apr 08, 2018 3:52 pm
somacast Joined: 08 Apr 2018 Posts: 4	much appreciated, thnx , i will disconnect r 21 for now and retest the av .

somacast Joined: 08 Apr 2018 Posts: 4	Posted: Sun Apr 08, 2018 4:31 pm
somacast Joined: 08 Apr 2018 Posts: 4	update: disconnected R21 , nothing improved, and worse display goes black after 2 mins, i will replace the cap and add the resistor before it and c

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