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 Post subject: Saturn SCART bright / flash losing sync issue
PostPosted: Tue Oct 22, 2019 8:02 pm 



Joined: 21 Aug 2013
Posts: 17
I've been fighting with my Saturn and Framemeister setup for the past 2 or 3 years. I've narrowed down the problem to when the screen goes bright, I lose sync between the Saturn and Framemesiter. Would love some guidance on what to look at next or how to modify the cables to avoid this. From all I've read I suspect the voltage is going out of spec when the screen gets bright and that's causing the Framemeister to lose it.

Many SHMUPs are unplayable as the screen drops out constantly. Twinbee and Parodius show this behavior constantly. This is the fastest I've found to be consistently reproducible: Launch Virtual On, Arcade mode, play as Temin and use a bomb.

I'm using a US Model 2 Saturn -> Euro SCART cable -> Framemeister

I've tried 2 different Model 2 Saturns, both have the same issue.
I've tried both a Csync, and Sync on Luma SCART cables from Retro Game Cables. Both have the same issue.
I've tried both types of cables with a RGC Sync Stripper build into the Framemeister adapter on both Saturns and I have the same issue.
I've tried adjusting the Framemeister Sync Level across the entire band and do not see an improvement.

My N64 is the only console with a similar issue. On there it's random ever 10-15 minutes that I see a quick drop out.
All other consoles work splendid over the framemeister.

Thanks!


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Tue Oct 22, 2019 8:43 pm 



Joined: 08 Mar 2017
Posts: 1105
Well, from your description I'd instantly point to Composite Video sync and recommend you tried CSync.
But since you've already tested that and (presumably) the symptoms didn't change, you have a different (and uncommon) issue.

Are there any devices between the console and your upscaler?
Have you tried a factory reset on the upscaler?


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Wed Oct 23, 2019 2:05 pm 



Joined: 22 Sep 2009
Posts: 132
Try adjusting the sync level. The Saturn can be tricky sometimes with the Framemeister.

Adjust the sync level up AND down one position and see if that fixes it. I have to do this on occasion (especially when capturing arcade board footage) and 9 out of 10 times it resolves any sync issues.

It's in the Sync menu. I believe its called "sync level" and it has a numerical value that can be adjusted in either direction


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Wed Oct 23, 2019 2:32 pm 



Joined: 08 Mar 2017
Posts: 1105
awbacon:
I think this case is not even related to sync levels or types of sync, as many different forms of it were tested.
At least one of those would have worked without hassle, if the issue was sync related at all.

I'd rather say this Framemeister doesn't like to see "high" voltage on one / all of the RGB lines (for some reason).


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Wed Oct 23, 2019 7:20 pm 



Joined: 21 Aug 2013
Posts: 17
I've eliminated all devices in the chain (Saturn to framemeister, directly to the TV). I've not recently reset all framemeister settings, but I did do that last time I upgraded firmware. I can try it again tonight and see if that changes anything.

I have played with the sync levels with each of the combinations going from 0 to 20 on each. I've probably launched a few hundred bombs as Temjin now. Each time the sync is dropped. It's on on some of the combinations I'll have bands of sync that work say 4-8 and then again from 12-18. Other consoles it's not a split range like that, just something like 0 - 7.

It's odd that this doesn't seem to happen with the other consoles. It's possible if it's happening on menus but I haven't noticed as the screens are transitioning.

rama: If my framemeister doesn't like the high voltage on the RGB lines, what approach would you suggest to diagnose? Try adding resistors to the RGB lines or is the solution really to just purchase another framemeister and see if that fixes it?


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Wed Oct 23, 2019 8:20 pm 



Joined: 08 Mar 2017
Posts: 1105
Do you have alternative consoles to test? I wonder if it's a console problem.

No, I wouldn't try to add resistors.
If the Framemeister shows issues that are not directly sync signal related, but only happen on sudden color changes, then something is wrong with the Framemeister (or console!).
If you can rule out the console, then I'd look around / ask in the Framemeister thread for similar issues.
You'll have to filter out all the sync level talk though.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Wed Oct 23, 2019 9:47 pm 


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Joined: 21 May 2013
Posts: 231
Do you have any pictures of the insides of the two SCART cables? I know you mentioned the cables are CSYNC and Sync on Luma, but some cables can be labeled as such yet actually use an LM1881 internally.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Thu Oct 24, 2019 12:28 am 



Joined: 21 Aug 2013
Posts: 17
I have two different model 2 Saturns and both cause the same issue at the same points through both sets of cables.

Genesis, NES (RGB PPU), SNES, Master system all seem to work fine through the same SCART input.

Photos of the two cables at the following link. I don't see any LM1881's in these. Though the "Csync cable" is definitely not as nice as the sync on Luma cable.
https://imgur.com/a/HEPnzIu


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Thu Oct 24, 2019 8:33 am 


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Joined: 21 May 2013
Posts: 231
nova1313 wrote:
I have two different model 2 Saturns and both cause the same issue at the same points through both sets of cables.

Genesis, NES (RGB PPU), SNES, Master system all seem to work fine through the same SCART input.

Photos of the two cables at the following link. I don't see any LM1881's in these. Though the "Csync cable" is definitely not as nice as the sync on Luma cable.
https://imgur.com/a/HEPnzIu

I understand you have tried two Saturns, but if we think about this logically, plenty of people are using Sega Saturn's with a Framemeister without issues. Since the Framemeister appears to be working correctly with all other systems, and if we rule out the possibility of both Saturn's being faulty, then the most logical conclusions is that its likely to be a cabling issue (I'm not saying it couldn't be something else, its just what seems most likely)

I assume the SCART cables are being connected to the Framemeister with a EuroSCART to Mini DIN adapter? If so have you checked inside the adapter to make sure there isnt an LM1881 inside it?

The CSYNC cable is definitely incorrect since NTSC Sega Saturn's output TTL level CSYNC so require a 470 ohm resistor and 220uF capacitor inside the cable (Which I very much doubt has been fitted inside the Mini DIN plug end of the cable)

For the Sync on Luma cable from RGC have you tested continuity to make sure it is actually wired for Sync on Luma and not CSYNC by mistake?

Finally I would be tempted to try a Sync on Composite Video cable as well (Or rewire the CSYNC cable as such) just to see if that makes any difference.

<EDIT> Just re-read the OP and noticed this line:-
nova1313 wrote:
I've tried both types of cables with a RGC Sync Stripper build into the Framemeister adapter on both Saturns and I have the same issue.

This adapter is very likely to be the cause of the problems. I would buy a new EuroSCART to XRGB Mini DIN adapter which is wired straight through without any built-in Sync Stripper (LM1881).


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Thu Oct 24, 2019 11:16 am 


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Joined: 06 Mar 2006
Posts: 11923
Location: Germany
Quote:
This adapter is very likely to be the cause of the problems.

indeed, especially since there's absolutey no reason in the first place to use a sync stripper on the FM's input.
If you like to continue to adapter, you need to attenuate the sync stripper's output (get a resistor in there). Or you ditch the adapter in favor of a 100% passive adapter solution.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Thu Oct 24, 2019 12:32 pm 



Joined: 08 Mar 2017
Posts: 1105
Do'h! I missed that, too.
It's got to be that adapter.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Thu Oct 24, 2019 12:50 pm 



Joined: 21 Aug 2013
Posts: 17
Sorry I was unclear about the Euro SCART to framemeister adapters. I own 2. One has a sync stripper and one is 100% passive without. Both had similar issues with both Saturns. I usually run without the sync stripper, but have the adapter for debugging purposes.

Good to know my "Csync scart" is wired incorrectly. I'll pickup a new version of that cable, but will try rewiring the current one until that comes in.
I'll check the Luma scart cabling wiring when I get home today.

I appreciate all the help.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Thu Oct 24, 2019 1:09 pm 


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Joined: 06 Mar 2006
Posts: 11923
Location: Germany
CSYNC cables are always up to their built-quality. The CSYNC output on Saturn units are way to high for most processors or displays, so a proper attenuation is neccesary. Luma should be pretty much "on spec", or at least easily in the range that the FM can handle itself using the sync level setting. In theory you have attenuate the luma level as well, but it shouldn't be neccessary.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Thu Oct 24, 2019 1:26 pm 


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Joined: 21 May 2013
Posts: 231
nova1313 wrote:
Sorry I was unclear about the Euro SCART to framemeister adapters. I own 2. One has a sync stripper and one is 100% passive without. Both had similar issues with both Saturns. I usually run without the sync stripper, but have the adapter for debugging purposes.

Good to know my "Csync scart" is wired incorrectly. I'll pickup a new version of that cable, but will try rewiring the current one until that comes in.
I'll check the Luma scart cabling wiring when I get home today.

I appreciate all the help.

Sounds like your best option then is to use the Sync on Luma cable (Assuming its wired correctly) with the passive adapter and see how that goes, then if you still have issues you can try tweaking the Framemeister's sync level setting mentioned earlier.

I personally always prefer to use a Sync on Luma cable with a Saturn because:-
-You dont need to worry about the CSYNC signal being potentially out of spec due to missing/incorrect components in the cable.
-A Sync on Luma cable will work with both PAL and NTSC Sega Saturn's (CSYNC output is only available on NTSC Saturn's, and if there is any possibility you might encounter/connect a PAL Saturn there is a risk of equipment damage because they have +9V instead of CSYNC on the same AV port pin)
-CSYNC offers practically no advantage over a well made Sync on Luma cable.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Sat Oct 26, 2019 9:16 pm 



Joined: 21 Aug 2013
Posts: 17
Verified my sync on luma cable is wired to Luma. Sync on Luma + Passthrough framemesiter adapter still causes dropout in Virtual On. Adjusting sync doesn't seem to do anything for it. I tried this setup on two Saturn consoles, both with the same results.

I ordered a csync cable and am waiting for that to arrive.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Mon Oct 28, 2019 12:12 am 



Joined: 21 Aug 2013
Posts: 17
Same issue when using the CSYNC scart cable.

Bought an Insurrection Industries Saturn CSYNC SCART. It's wired correctly. I used it with the straight through adapter for the framemeister. Launched a bomb again in Virtual on and the screen went black. :/

I guess that leaves the straight through adapter and the framemeister to try swapping out.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Mon Oct 28, 2019 9:36 am 


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Joined: 21 May 2013
Posts: 231
If thats the case (and the new CSYNC cable has the correct resistor and capacitor) then the only other things I can think of are:-
-Double check the new CSYNC cable and passive adapter are definitely passive and dont have a hidden sync stripper internally.
-Try using a Sync on Composite Video cable instead, since thats the standard/expected signal on SCART and JP21 cables.
-Try using some older versions of the Framemeister firmware and see if they make any difference
-Beyond that I guess you could recap the Saturn, but i'm not convinced that will really make any difference.
...Just checking but have you tried using different TV's, just to rule that out? I realise its extremely unlikely, but it is the last part of the video chain.


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 Post subject: Re: Saturn SCART bright / flash losing sync issue
PostPosted: Thu Nov 07, 2019 1:52 am 



Joined: 21 Aug 2013
Posts: 17
Sorry for the slow follow up. Thanks for all the feedback. The issue has sort of been resolved. I'd still love for any ideas or if someone can explain why a monitor swap appears to have partially resolved the issues.

The partial "fix" setup is Saturn -> Luma Sync SCART cable -> Passive adapter -> Framemeister w/ sync level 15 -> a different display (thanks Link83 for the suggestion!).

Swapping the display caused most of the issue to go away. Csync didn't allow me to stop the drop outs even by adjusting the sync level. Swapping to the Luma sync cable and adjusting the sync level makes it happen way less. The games are playable now.

Why only a partial fix? I can still trigger it occasionally, but it's rare. Virtual On, on a bright stage (first level), if both players are close and launch a bomb at the same time it will still drop out. The screen at that point has two layers of a checkerboard pattern on it and then you can see a second of tearing in the picture before it goes black. I usually do not lose HDMI lock at this time, but occasionally that will happen too. It takes about 10 seconds to recover when this happens.

Previously I was using a Dell U2711 monitor. I swapped to a borrowed Optima 1080p projector and that seems much better. So I'll have to look for another display for my games.

Other things I tried before swapping the monitor:
I've double checked that the CSYNC and passive adapter are definitely passive.
I didn't have a sync on composite cable, so I could not try that.
Add a Dr HDMI in line to lock the EDID during the HDMI block out.
I tried using s-video from the Saturn to the Framemeister and did not have issues.


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