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PostPosted: Mon Jun 30, 2014 9:15 am 
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Hello.
Recently I got an american SNES. Thought to myself, that it would be nice if I fitted SuperCIC in it. And that's what I did. After soldering everything together, turns out it doesn't work - the screen comes on , but there is strange flickering (something like on a videotape - when it slides in the VCR), also there are no colors. Alright, i checked my soldering, turns out there are two pins shorted together (I think 7th and 8th on the CIC). I check again, and now it is working - but only in 60Hz (Red) mode. As soon as I switch back to 50 the colors are gone, and some skew lines appear, but the flickering is gone.

I checked everything again, and everything is fine, there are no shorts. So why does it not work? I don't know.

Here's some info:
-I removed the CIC completely and connected pin 8 to GND (on some NEC memory)
-I took +5V from PPU1
-The system is powered from a 12V DC adapter rated at 1.2A, stepped down with a DC-DC converter to stable, filtered 10V (I live in the Europe, didn't bother to buy a transformer for the power supply)
-Maybe something is wrong with my TV? But then why is it working fine in 50?
-I checked some PAL games as well as some NTSC games, and the problem persists

I managed to take a photo of this:
Image

Anyway, if You have any ideas let me know, because I'm through with this, and just want to finally finish this project.


Last edited by Kaqun on Tue Jul 15, 2014 8:38 am, edited 1 time in total.

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PostPosted: Mon Jun 30, 2014 9:30 am 
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Location: Seattle
The diagonal lines make it look like it's continuing to modulate using NTSC color encoding even when running at 50Hz, and maybe your television can't parse System B/D video with NTSC color encoding?


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PostPosted: Mon Jun 30, 2014 10:24 am 
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Honestly I have no idea if my TV has an ability to parse B/D with NTSC color encoding :mrgreen:. And the documentation doesn't say anything.

Now, I tried the SNES with my old CRT - it works the same, that is: black and white in 50Hz mode, but the lines are gone.
On my parents' TV it works the same as on mine.

I don't know where to look for the problem - is it the SNES or my TV?


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PostPosted: Mon Jun 30, 2014 1:05 pm 
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Location: Seattle
Proooobably your TV?

Looking more carefully, I see ~180 color cycles on screen on a scanline (picking a random scanline of green in the background). For NTSC this should be ~170 (3.6MHz ÷ 15.74kHz × 3/4), and for PAL it should be ~210 (4.43MHz ÷ 15.63kHz × 3/4), so it looks to me like it is NTSC color.

There is a color modulator somewhere on your board (BA6592, S-ENC, S-RGB). At least for the BA6592, one of the pins can be toggled between NTSC/PAL color encoding (producing PAL-B / PAL 60), but you'll also need to feed it the correct colorburst frequency, possibly by changing or adding a crystal. Hopefully your TV can correctly parse PAL 60... it at least seems more likely.


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PostPosted: Mon Jun 30, 2014 2:11 pm 
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I have a stock NTSC SNES, but I had to get a RGB cable to get it to work(I'm from Sweden).
Could that be your problem?


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PostPosted: Mon Jun 30, 2014 11:42 pm 
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By using a RGB cable you bypass the need for any NTSC or PAL color encoding. He must be using Composite or maybe S-Video. If his TV accepts RGB via SCART he should definitely use it. It would both solve the color problem and improve image quality.


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PostPosted: Tue Jul 01, 2014 8:41 am 
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Thanks everyone.

You are right, I'm using just a regular composite cable that came with my GameCube

Damn, and I thought I would get away wihout any additional shopping :mrgreen:.

Okay, I'll buy that RGB cable, I was thinking about this one (fairly close to my country): http://www.ebay.pl/itm/SNES-RGB-Scart-Kabel-mit-Cinch-Ausgangen-Audio-Video-Out-gebraucht-/201112319423?pt=PC_Viedeospielzubeh%C3%B6r&hash=item2ed33a75bf&_uhb=1

But from what I've seen RGB cables for NTSC and PAL are different. Is there any difference in their operation?

Also lidnariq, do You have any additional info about BA6592? Like datasheet or anything?


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PostPosted: Tue Jul 01, 2014 9:32 am 
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Joined: Sun Apr 13, 2008 11:12 am
Posts: 7400
Location: Seattle
Kaqun wrote:
Also lidnariq, do You have any additional info about BA6592? Like datasheet or anything?
Found this: http://console5.com/wiki/BA6592F

It's a little light on details, unfortunately. Only thing I actually found useful was the last page of the linked datasheet (where there's an example schematic).

Jwdonal's redrawn SNES schematics show the BA6592F in the US/Japanese SNES is fed by clock divider in the S-PPU2, rather than a separate crystal. It looks like the rework to convert to PAL is: cut jumper SCLN, solder jumper SCLP, remove R29, L1, C11, R28, C9, add a 4.43MHz xtal, 25pF and 66pF capacitors, and 560Ω resistor between Vb and Va (pins 14 and 15).


Last edited by lidnariq on Tue Jul 01, 2014 10:24 am, edited 1 time in total.

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PostPosted: Tue Jul 01, 2014 10:13 am 
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Kaqun wrote:
Thanks everyone.

You are right, I'm using just a regular composite cable that came with my GameCube

Damn, and I thought I would get away wihout any additional shopping :mrgreen:.

Okay, I'll buy that RGB cable, I was thinking about this one (fairly close to my country): http://www.ebay.pl/itm/SNES-RGB-Scart-Kabel-mit-Cinch-Ausgangen-Audio-Video-Out-gebraucht-/201112319423?pt=PC_Viedeospielzubeh%C3%B6r&hash=item2ed33a75bf&_uhb=1

But from what I've seen RGB cables for NTSC and PAL are different. Is there any difference in their operation?



For the NTSC systems, buy the GameCube RGB cable. PAL SNES systems use a slightly different RGB cable. There is no worry about the GameCube cable since only a PAL RGB cable exists for GameCube, the NTSC versions lack RGB output entirely.


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PostPosted: Mon Aug 25, 2014 7:14 am 
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Yop, You were right. I finally got that RGB cable, and everything works like a charm!
Thanks :mrgreen:


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