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Post by caseh on Apr 16, 2015 17:16:12 GMT
So I've tried my Saturn with a cheapo RGB and the ones recommended in another thread on this forum (from thefoo83 on eBay) and the display and interference are identical. Quite easy to notice on the dash, when the disc seeks there's visible interference along the top of the screen, where the track detail is displayed.
Its not really notable in game, just on static screens if I'm paying attention. I'm using a 48 inch HDTV rather than a CRT so I'm just wondering if this is normal for newer TVs?
For what its worth, if you're interested do a search for Hellfire RGB they're about 1/3 the price of the more expensive cable.
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Post by zyrobs on Apr 16, 2015 18:45:40 GMT
Quite easy to notice on the dash, when the disc seeks there's visible interference along the top of the screen, where the track detail is displayed. That's the fault of the console, not the cable. It happens in VA6 to VA9 machines, regardless of the cable. As I recall it is less noticeable on a CRT.
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Post by caseh on Apr 16, 2015 18:54:00 GMT
Gotcha, makes sense. I have a va9 and its not really an issue but its worth knowing, thanks for the confirmation.
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Post by buckoa51 on Apr 16, 2015 22:35:09 GMT
Happened on the model 1 I had in for testing too, I think the only way to completely guarantee to eliminate it is to use a clean sync cable and NTSC console.
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Post by zyrobs on Apr 17, 2015 0:29:32 GMT
Happened on the model 1 I had in for testing too, I think the only way to completely guarantee to eliminate it is to use a clean sync cable and NTSC console. I've never seen it happen on any model 1s. What motherboard type was that machine? (what was the serial?) I doubt clean sync would make a difference, since it is not the composite video causing the interference. I suppose I could dig out my Hi-Saturn 2 to test, I think I still have a cable that I can change the wires in to get c-sync access.
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Post by buckoa51 on Apr 17, 2015 8:28:33 GMT
Clean sync has definitely solved it for me in the past, but I have also seen machines where it doesn't happen when using standard composite video for sync.
Sorry I didn't record the serial number of the console, but it was a PAL Model 1 definitely a genuine model 1 not a board swap as it had a Rhea in there.
Also, the white NTSC Saturn I have that doesn't have the problem is supposedly a VA9 motherboard, but I have not owned it from new so it could be a board swap.
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Post by zyrobs on Apr 18, 2015 0:59:13 GMT
Clean sync has definitely solved it for me in the past, but I have also seen machines where it doesn't happen when using standard composite video for sync. Okay, that definitely sounds like a badly shielded cable then. The interference the CD drive causes is visible on all cables, even composite or s-video. That narrows it down a lot. Did it have a top mounted PSU (VA0) or a bottom mounted with a separate controller board (VA1)? Can you check the serial of that unit? VA9 was never put in white saturns, but white saturns had boards from VA2 to 15.
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Post by buckoa51 on Apr 18, 2015 10:12:53 GMT
Why would that only affect some of the colours though?
I don't know which controller board the model 1 had, sorry (and is no longer in my posession).
Maybe I'm reading it wrong - AC79501648 is the serial on the outside.
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Post by zyrobs on Apr 18, 2015 16:05:50 GMT
That's a VA5. The extra 9 is there to indicate that it has been refurbished.
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Post by buckoa51 on Apr 18, 2015 16:44:18 GMT
Ah okay.
I wonder if there's more than one issue here, I'm seeing interference in light blue colours only on some machines, but actually it seems to happen all the time, not only when there's disc access.
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Post by caseh on Apr 18, 2015 17:48:56 GMT
Ah okay. I wonder if there's more than one issue here, I'm seeing interference in light blue colours only on some machines, but actually it seems to happen all the time, not only when there's disc access. It's always there on mine as well but its marginal. Out of curiosity, what kind of TV are you using it on and how big is it? Stretching a low res image across a HD display is bound to amplify the interference making it easier to see, in my case anyway.
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Post by buckoa51 on Apr 18, 2015 18:14:26 GMT
Sony KDL-40Z4500 with XRB3 or XRGB Mini. It's definitely NOT there on my Japanese Saturn, I tried my Japanese Saturn with a really cheapy crappy cable (composite video for sync) and it still didn't show the interference.
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Post by caseh on Apr 18, 2015 19:08:33 GMT
Sony KDL48w605 for me, if you don't mind me asking is the XRGB mini worth it? What can it upscale the Saturn source output to? Quite curious about it as I'm also looking at dreamcasts and my TV doesn't have VGA, typical.
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Post by zyrobs on Apr 19, 2015 3:33:28 GMT
Okay, I tested a couple of different setups to check when the problem happens and when does it not.
Just to be clear, the problem in question is a visual anomaly on model 2 Saturns that use motherboards between version VA6 and VA9. The anomalies include a constant bend at the top row of the image, and smaller, minor bends appearing on random lines anywhere else. The random line problem is worse when the CD Drive is loading or playing music, and even more worse when the CD Drive is seeking to another location on the disc.
All tests were run using the RGB Scart cables purchased from ebay seller thefoo83, since these work on all Saturns, both NTSC and PAL. The official Sega-made RGB Scart cables only work (properly) on PAL units due to a pinout difference on the console a/v connector between NTSC and PAL units. This cable is wired to use composite video as per the SCART specification.
First, on my plasma TV, a Panasonic TX-P42G10E: - VA7 PAL unit: the problem exists and is very easy to spot, the entire screen has random bending running around on it. - VA9 NTSC unit: the problem exists but it was fainter - harder to spot, harder to notice during games but it was definitely still there.
Just in case it is the power supply causing the problem, I put the 220v power supply into the NTSC unit, but it made zero difference on the video output.
Then I checked a CRT (some noname display, BEKO or something). The problem was still there, but it was so hard to spot you wouldn't ever notice it unless you looked for it. But this was not because CRTs handle the signal different. It was a combination of things: - this was a low end TV, while my Plasma is a high-end one, - CRTs displaying pixels differently than modern digital displays (this one used in-line shadow mask), - phosphor afterglow, - lack of calibration: the picture was not a proper square to begin with, - it also had random lines bending, also regardless of the console, - this TV is just much smaller! My plasma has a display almost three times the size, which makes visual anomalies easier to spot than on this old CRT.
I hooked up two different model 1 Saturns (a VA0 PAL and a VA3 PAL), and they didn't look much better - the permanent bend on the top was gone as expected, but it was extremely difficult to tell, I had to check the corner from 20cm away, which is not how you would usually watch TV. Also tried this using the official cables which are slightly higher quality: no difference whatsoever, and I was trying very hard to spot anything.
Finally, I hooked up the VA9 NTSC unit to my projector (SONY VPL-CS4), which *requires* Composite Sync to work with 15khz RGB input. Composite video is not usable for RGB input, only composite sync a.k.a. "raw sync". For this, I used a SCART cable that came with PAL units. On PAL Saturns, the C-Sync output pin was changed to output 9V DC instead, as it was required for the SCART standard for auto switching. So by using this cable in a NTSC unit, I could just tap pin 8 of the SCART connector; this would be a 9V signal on a PAL unit, but C-Sync because I was using a NTSC unit.
I had RGB and C-Sync aka raw sync used for a connection, using the highest quality official SCART cable, hooked up to a VA9 NTSC unit. The result? No difference. The bending on the top right corner is there, and I could see the bent lines running around as well, when the CD Drive was seeking tracks. In fact it was even easier to spot then on my plasma screen, due to the fact that I was projecting a 2 meter 4:3 screen versus the 42 inch (~106cm) 16:9 display on my plasma tv (when set to 4:3, the picture was even smaller on the plasma). It also helped that the projector did nearly no image processing, and due to its native resolution of 800x600 (almost exactly the same as the consoles output), it also produced a much sharper image.
Also checked using composite video on my plasma and on the projector, and the artifacts were there using both.
Conclusion: this is definitely a hardware problem in the consoles. For some reason, it is also way more sever than on NTSC units. Cable type will not improve on the problem, other than poorer cables possibly introducing other issues. Composite, RGB, RGB + raw sync, all of them had the issue equally. VA0 to VA5 units don't seem to have this problem (I specifically checked a VA0 and a VA3 right now, but in the past I've also used VA1, VA2 and VA4 units, and none of them had the problem either).
I think this issue went unnoticed simply because on a typical CRT, you just can't notice it. But modern displays are much higher quality, which emphasizes the problem greatly. I wonder how visible this problem would be on a high quality CRT, like a properly calibrated Trinitron studio display - likely more visible than on the CRT set I used.
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Post by buckoa51 on Apr 19, 2015 11:23:26 GMT
Ah right, that's not the issue I'm seeing. The issue I'm seeing is a moving interference pattern in light blue colours (for instance the track selection at the top of the BIOS screen). I tried one of the thefoo83 SCART cables, no different to my super cheap SCART cable far as this problem is concerned. On my Japanese VA5 console though, no issues with this problem using clean sync or composite video for sync. Though I'm pretty sure I switched to clean sync to cure it in the past (as with a similar issue on the PS1 where you can use luma for sync instead).
720p or 1080p. Your Sony is one of the less hideous TVs when it comes to scaling 240p, nevertheless I wouldn't even consider setting up a Saturn on a HDTV without one these days. Difference is night and day.
It's not really much help for Dreamcast though since so few games are 240p, I'd go VGA to Component there.
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