OSSC sync settings required with Sega Mega Play hardware

[Layer]

Hi everyone ;),

I’d like to know if someone has tried to use Sega Mega Play (arcade hardware) with an OSSC.
In fact, I use an RGB SCART from my supergun (Sega Genesis compatible), I let OSSC default profile, I turn “Allow TVP HPLL2x” option to Off, I move “Analog sync Vth” option to 146 mV to get something displayed, but it’s still instable.
What would be the more accurate settings to try to get this hardware stable ?

Thanx in advance 😉

• This topic was modified 2 years, 6 months ago by Layer.

[BuckoA51]

Which Supergun do you have? Have you tried changing PLL coast values to 4 as well?

[Layer]

Thanx for your reply 😉

I use a Vega Jr. supergun. Gonna try to change PLL coast values to 4 and post the result.

[Layer]

Tested.  PLL coast values to 4 don’t change anything.

The sync is still instable when I try to play or insert coin and always changes from :
AV1-RGBS 262-P
15.69 kHz 59.91 Hz

to :

AV1-RGBS
NO SYNC

• This reply was modified 2 years, 6 months ago by Layer.

[marqs]

Any chance you could try v1-series beta firmware (requires a small hw mod)?

[Layer]

Thanx for the reply 😉

It could be a good idea and may fix the sync issue, but I don’t know if a micro SD card with less than 1 GB storage is enough to update to your “Beta” fw.

I only have a small micro SD card I formerly used with a linker for N3DS.

[BuckoA51]

Are other boards working ok on your Supergun? I’m not familiar with that model unfortunately.

[Layer]

Most of the ones tested work well (PGM, CPS-1, CPS-2, MVS, Sega System 18, Data East PCBs…) with OSSC, but I have a lot of PCBs not tested yet.
Vega Jr. supergun has Mean Well MWP-602 110V/220V switchable PSU, like Sigma Raijin and Hakuryu. I only have to set/check +5V (between 4.8V and 5.15V) when I want to play.

• This reply was modified 2 years, 6 months ago by Layer.

[marqs]

@Layer 1GB card is easily sufficient for the update. The update procedure is shown here.

[Layer]

I’ve done the mod, I’ve removed the SMD resistor (R35) and put a wire between U1 (pin 25 on the last side as in the picture) and the pad of R35.
I’ve updated to Beta fw 1.06a marqs, now everything looks OK, but there’s no better sync when I try to launch a board with the supergun.
Is there something to do to autosync ?

I’ve reupdated to official release fw 0.90, everything works like before, then I’ve reupdated to Beta fw 1.06 and tested Sega Mega Play, it runs like with fw 0.90, the sync is not better.
Btw, I don’t happen to get PGM and CPS-1 systems syncing with Beta fw 1.06.

• This reply was modified 2 years, 6 months ago by Layer.
• This reply was modified 2 years, 6 months ago by Layer.

[Layer]

I’ve done more tests :

CPS-1

Banpresto PCB (Denjin Makai 2)

Sega System 18

PGM

Namco System 2

Sega Mega Play still has sync issue and AtomisWave doesn’t sync at all.
I use LG C2 42″ OLED TV.

• This reply was modified 2 years, 6 months ago by Layer.

[marqs]

Btw, I don’t happen to get PGM and CPS-1 systems syncing with Beta fw 1.06

But your pictures show both CPS1 and PGM running on 1.06 (HDR options are not present on 0.xx fw)?

I’m not sure what could be causing Sega Mega Play sync issue, I would have guessed sync is more or less similar to MD. On Atomiswave, are you taking video via VGA or JAMMA. Is the mode switch on 15kHz or 31kHz position?

[Layer]

In fact, it’s easier to get CPS-1 and PGM syncs with 0.90 fw than 1.06 fw, but it’s easier to get Namco System 2 and Denjin Makai 2 with 1.06 fw than 0.90 fw.

I believed Sega Mega Play was like an MD, but MD profiles didn’t help at all.

I’ve tried Atomiswave via JAMMA port in 15 kHz (not in VGA).

And I didn’t get Green Beret/Rush’n Attack PCB syncing at all, even with NES profiles.

[marqs]

In fact, it’s easier to get CPS-1 and PGM syncs with 0.90 fw than 1.06 fw, but it’s easier to get Namco System 2 and Denjin Makai 2 with 1.06 fw than 0.90 fw.

Can you elaborate what do you mean by ‘easier’? Which setting(s) you need to tweak to get stable sync?

I’ve tried Atomiswave via JAMMA port in 15 kHz (not in VGA).

Can you try the VGA port as well and 31kHz?

I suppose Mega Play and Green Beret syncs would need to be checked with a scope to understand what is going in there. I also wonder which kind of sync circuitry the Vega Jr. supergun has.

[Layer]

I mainly use default settings with :

Video in proc/Video LPF 9MHz (SDTV)
Video in proc/Pre-ADC Gain 4 (if I let default 8, white is too clear)
Sampling opt./Allow TVP HPLL2x Off
Sampling opt./Adv. timing tweaker 240p or 256×240 or 320×240 or 640×480 (depending of the game played)
Sync opt./Analog sync LPF 2.5MHz or Off
Sync opt./Analog sync Vth 123 to 169 (depending of the game played)
Output opt./256×240 aspect 1:1 PAR
Settings opt./Initial input Last used

I have tested Atomiswave in VGA and via JAMMA port in 31 kHz, and got no sync. I think my settings are not enough complete. Could this hardware mod be useful ? https://junkerhq.net/xrgb/index.php?title=OSSC_AV3_use_AV1_RGB_mod

Vega Jr. supergun has a small board with an LM1881, same board used in Sigma Raijin supergun.

[Author]

Posts