s18: CRT problems #692
Comments
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You could associate the length to the debug_bus, so users can try a few manually |
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Just FYI using DV I have: |
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I have compiled the core for varying manually the length of HS and VS To do so, please press the keys [+] or [-] (or equivalent to where they are in the Spanish keyboard) to adjust horizontally and "Shift + [+]" or "Shift + [-]" to adjust vertically. I leave the position of the keys in the Spanish keyboard below for reference. To go back to the original settings, Press either "Ctrl + [+]" or "Ctrl + [-]" An eight-digit number should come up in the bottom of the screen when doing so. The four digits on the right are associated with HS and the 4 in the left with VS. Please let us know if there's an eight digit combination that works for you.
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My test on PVM Panasonic BT-1415DA |
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Are Sync width and sync length the same thing ? |
Yes. The important parameters are the synchronization signal frequency and its active time (expressed as pulse width or length) |
Having the option to modulate the vertical sync width in all Cores would be a dream for all high end Ikegami monitors owners (probably JVC DT-V owners also). It is currently only available in a few Cores. |
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Played around quite a bit with this test Core but could not get any non-scrambled image to display on the 2950. |
Same here, implementation would benefit from H+V adjustments within the visible GUI via HDMI to stabilize CRT syncs. |
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'Dirty' S18 core control pads don't respond after before/after config for me, I couldn't get a coin to insert to further test game inputs on either game. Thanks |
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FYI ] and / are the US Keyboard equivalents of + and - |
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Went through all 255 possibilities (I assume only the top octet should change?) and did not find anything that synced. Values ending in 2 seemed to be the closest, with no rolling but still clearly off. Sony KV35V75 running svideo. |
Thanks. Have you tried the core via HDMI? the Core will not add coins, the BETA does. |
I did but I didn't even try to insert coins. I spent the whole time stepping through the sync values. |
its likely a debug core , made with no inputs/sound |
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So far three users tried this debug build and it only helped one (@Schermobianco). @Schermobianco's video is not available anymore but I think the result was that going from a zero to a non-zero value made it visible. I measured the PCB and found that HS was 6% longer there (equivalent to 2 pixels). I have modified the core to match the PCB length (b7015c2). The extra 320ns may help some users but from the reports here it looks like this change will benefit few people. HS signal measured on the board: 5.32us active time length |
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Hi @jotego , no it doesn't help me the better sync I had was the same as the original core (top left sync issue)
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Is the updated Core compiled and available? Thanks. |
My photo is from the test core, the updated core compiled isn't available right now |
Gotcha, I ran the updater incase Jose added it to Update all, I got my fingers crossed it improves CRT sync compatibility for many CRT users. |
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I tried the first custom core posted. I tried every combination available but nothing synced the picture (Sony PVM). @jotego when will the new core be posted? will it be combined into the update_all core or will it need to be manually downloaded? |
This version has exactly the same HS/VS signals as the original board. Let me know if it works. |
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Thanks for testing it. We will build another debug version just focusing on HS as it looks like the vertical signal gets locked correctly. |
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@jotego I tried the new core in jts18_8db7b95.zip and this is what i got. same as the original core. sd.mp4 |
I've got the same image on my arcade (Toshiba tri-sync monitor) |
JT in my case it's worse |
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JT, does not work for me either. |
No luck on the PVM-2950. |
Ask here. Another option is RetroArcadia (Tel 615237811). |
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JT, RetroArcadia con Ruben. Genial! |
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I also have Sega System 18 core sync problems with my Sega Aero City and it's Nanao MS8 -monitor. Every other Mister core works flawlessly on it. If that's valuable info I have Sega System 18 Multi (from Arcade Projects forums) too. It has Clutch Hitter as donor board. Original Clutch Hitter board and Multi afterwards has worked with the same monitor setup without problems. |
I'm seeing quite a few owners of original S18 PCB's say they have no problem with S18 sync. . |
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As explained above, the voltage levels are different. That is not set by the core but by the external DAC. I do not think there is nothing to do here from the core side. I am closing this issue. |
Hey Jose, I scrolled above, but did not see an explanation about DAC voltage levels being different from the original PCB, apologize if I missed/misread anything. Gracias. |
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Here it is: #692 (comment) As I said, core-wise I cannot do anything effective. I could add more options but I think it is not going to help. I can modify the core speed, and that may lock the signal better in those screens with problems but at the cost of altering the gameplay. MiSTer hardware vendors could add a voltage adjustment to the DAC output for this. That is rather common in supergun devices to connect arcade PCBs. This would require a new IO board or an adapter. There are probably things one can do to the signals between the MiSTer and the TV set to fix this. Most notably, changing the voltage levels, changing the line impedance and limiting the bandwidth. We may try to limit the bandwidth at the core output a bit, as part of the work we are doing on a different topic. That may help but I cannot know for sure. If I had one of these screens, I would service it and replace all capacitors. By the way, I can see a similar effect on my CRT with a completely different core. Ghosts'n Goblins video output does not get synchronized until the game gets to the screen full of capital H characters. After that, the TV is able to lock it in. So even the video content can have an effect on the PLL locking the synchronization signal. That clearly points to noise coupling inside the TV set. My point is that video locking is a sensitive analog signal processing and tiny things can disturb it. |
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Another solution for troubled users is to use MiSTer's composite output instead of component. There is a chance that may work as the signal goes through a lot of processing that will alter the conditions for the PLL synchronization circuit. |
Sorry I did see that post before, but did not make the connection as to the difference being with the DAC. Is there a chance that if Directvideo mode is used via HDMI to VGA that output may play nicer with CRT's? If not then outside of using Composite, which isn't really an option for me, then it is an unfortunate reality. It's a shame there isn't a solution whereby the Core could increase the DAC so incrementally that the game would only be sped up by say 1HZ or so till the Screen sync's.. Thanks again. |
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The core just does not have control over the amplitude of the HS/VS signals on the IO board. |
Gotcha, now I have learned the limitation of the Core-DAC relationship regarding sync issues such as this, this has been valuable for me to learn and hopefully others. |
I tried component and im geting the same out of sync issue. I also tried jts18_6ae69c20.rbf.zip and i didnt work on my Sony PVM |
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The core is running at 15kHz and thats way out of spec for most consumer TVs, the cores resolution needs another mode that makes CRT's happy. Something like this:
If its really the HSYNC length, that should be very easy to decrease to ~4.5us, might be worth changing both |
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Indeed, there is a good chance that speeding up the game would make it more friendly to screens. We may add a general feature to JTFRAME to support this in all cores. It would have the side effect of altering the speed of everything, including music. Such a feature may need at least 3 weeks of work to get implemented and many Patreon subscribers hate to see the game release flow interrupted, so it is not a task we can embrace blindly. |
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It shouldn't affect the games speed, the pixel clock and all clock frequencies stay the same. It only adjusts the games video timing e.g. screen refresh rate or h freq for a crt. Just adjusting the hcnt would help in this case. |
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Hello, @jotego. How's going. |
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Hey @rogersouza-work do you have an hfreq/hhold adjust? Most of my arcade monitors chassis I tested have needed a slight tweak to those to sync but then they are good to go |
It's not your monitor, like Daniel mentioned, it's the hfreq that needs to be adjusted by your monitor if you can or better in the core itself. It's a wip for the core |
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I do think that the monitors do play a role here too, not just the signal frequency. It is a combination of the frequency and voltage of the signals, plus whatever the monitor was designed to tolerate, plus the effects of aging components. We do not have numbers for this, but this core seems to be the most troublesome core so far for CRT users. Not 100% of users though, there have been plenty of reports of users having no trouble at all. |
I have the same issue with sync with the sega system 18 core and a nanao MS9 chassis, original board works fine just like yours |
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@konradpop the adjustment for MS9 that impacts horizontal hold is on the main chassis just give it a slight tweak. (HS Limit I believe is the name or HH 15 I forget which) I barely tweaked mine and all cores including system18 have synched fine ever since on my MS9. Anyone with MS8 or MS9 with sys18 it’s either you need to tweak the pot or the pot has gone bad and needs deoxit/replacement but it’s totally solvable unlike some other crts |
Some monitors are troubled with JTS18 analogue video output. Try this:
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