Getting seperate luminance/chrominance out of Comag S 1003/12

rjg_scotland

I've posted this on Maiden's board but having noticed this section I thought it might be a good idea to post here too.

I'm finding the composite only output of my Comag S 1003/12 annoying (and SL-35, but I don't care about it so much)... actually, make that bloody annoying. It would be fine if I was just viewing the output on a small TV, but I'm viewing it on a 32" CRT TV. The comb filter in my TV isn't bad and I'm getting little in the way of dot crawl, but I am getting noticable rainbow effects on fine patterns and general lack of sharpness. I have my freeview box (old Philips On Digital box) and old Sony DVD player - both which do RGB - daisy chained to the RGB scart input.

Now, I realise getting RGB out my Comag(s) isn't going to happen but what I am wondering is if it's likely (has anyone tried poking around?) that the seperate luminance and chrominance signals are available somewhere about the board? I could at least then use it with S-Video input on the TV.

What are peoples thoughts on this?

Thanks!

Llew

What processor chip does it use? Would think it has RGB or Y/C out as well as CVBS, although if only CVBS is set by the software, you won't have them output by the chip.

Llew

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rjg_scotland

It's the Ali M3329 B1. Here's a pic of the board with the heatsink removed: _http://pics.rguk.eu/comag_jtag/DSCF1150?full=1
Here's one from a slightly different angle but with a graphics card heatsink installed: _http://pics.rguk.eu/comag_jtag/DSCF1170?full=1

The original firmware doesn't let me choose anything other than composite, the latest Truman does but it doesn't do anything. I don't think there's anything other than composite connected to the SCART connector hence wondering if it's likely I could get luminance and chrominance seperate from somewhere on the board if not RGB.

Llew

You starting point would I suppose be a pinout diagram of the chip. Unhappily I couldn't source one online, and I don't know the receiver, so can't help much there.

Llew

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rjg_scotland

Thanks for your help anyway Llew, I had a look just there myself and have found this datasheet _http://0e1.org/cms/Ali_M3329_Datasheet/

I need to apply a screwdriver to my hifi at the moment as the rear speaker outputs have stopped working, but I'll sit down in a wee while or perhaps this evening and examine the pin out and see if I can work it out.

Cheers!

Llew

Don't think that datasheet will help much rjg - just data interfaces to another chip as far as I can make out, must be a separate D/A video processor chip on the board somewhere.

Llew

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rjg_scotland

Yeah I was thinking that but I can't find one! I can find the SPDIF D/A convertor for the audio but nothing for the video. I've traced back from pin 19 on the scart which is composite out and it seems to just disappear to the main CPU...





Perhaps I'm just following it wrong...

You're right this looks just data out to a D/A chip interface:

Cheers

rjg_scotland

Ah well that's that. Shorted something by accident (Scart pin 19 and that first large capacitor +ve side) and I've blown something and now I have no video output. Serves me right for poking about I guess. Shame but the box was free so I've not lost anything financially...

Time to save up and buy a better 2nd hand box with RGB output I think.