I use an ossc myself for testing miniguns and can confirm, every time, without fail, powering on for the first time without any adjustments results in too much "brightness"/intensity. The "default" positions fresh out the box have never been good on any of my builds, but heading to color bars and doing some quick tweaking always does the usual magic.
- Thread starter Frank_fjs
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I use an ossc myself for testing miniguns and can confirm, every time, without fail, powering on for the first time without any adjustments results in too much "brightness"/intensity. The "default" positions fresh out the box have never been good on any of my builds, but heading to color bars and doing some quick tweaking always does the usual magic.
Color bars look OK to me.
It is very possible that I'm just being overly picky... I only see the problem when there is a LOT of white on screen (opening title for Street Fighter II as an example).
Raph_friend
Grand Master
White (brightness) is handled by BLUE and a bit of green. Take your time messing with potentiometers, you will understand.Color bars look OK to me.
It is very possible that I'm just being overly picky... I only see the problem when there is a LOT of white on screen (opening title for Street Fighter II as an example).
Will do. Thanks.
Color bars look OK to me.
(not my pic just snagged it off google real quick for the example)
I usually prefer using the color bars found in boards like the cps2/3 where there's a very clear "opacity" scale. On a fresh-install minigun, most of the entire bar(s) will be a solid color; the entire scale appearing how this images rightmost sections are, but after tweaking, the differences between contrasts will be much more clear between every step of the scale (and by extension, "correct").
(not my pic just snagged it off google real quick for the example)
I usually prefer using the color bars found in boards like the cps2/3 where there's a very clear "opacity" scale. On a fresh-install minigun, most of the entire bar(s) will be a solid color; the entire scale appearing how this images rightmost sections are, but after tweaking, the differences between contrasts will be much more clear between every step of the scale (and by extension, "correct").
I was using a dedicated test board, but I'll hook up my CPS2 or CPS3 and see how they look.
Edit: OK, so checked my CPS2 and there is definitely less definition of the colors at the higher values compared to the reference.
Also managed to capture the washed out effect, so I know it's not the LCD. Will work on tweaking the potentiometers this weekend.
For my own reference, current values in kOhms.
R: 0.971
G: 0.943
B: 0.985
Will try turning down to around 0.75kOhms
And fixed: thanks @GeeDee & @Raph_friend
Last edited:
GeorgeSpinner
Grand Master
It will be different from board to board, but hopefully your test board and other boards are similar enough.
I use OSSC profiles and CRT display profile to account for boards that are drastically different in output.
I also have a passthrough pcb that allows me to adjust H, V, and brightness on the minigun that is not dedicated to a single PCB.
You probably just need to turn counter-clockwise on all 3 just a smidge.
I have them all set in the same position.
Edit:
I guess I wasn't replying to latest.
I'm glad you got it sorted out.
Orakelschaf
Student
Hello everybody,
i am about to build the 1.7 version of the mingun (since somebody gave standard/advanced pcbs to me
) - I got a minor question: What are the switches (SW3, LPF, SW4) for?
Thanks alot!
i am about to build the 1.7 version of the mingun (since somebody gave standard/advanced pcbs to me
) - I got a minor question: What are the switches (SW3, LPF, SW4) for?Thanks alot!
SW3 = button 4 on jamma edge on/off, by default the MGSG sends B4 to both the JAMMA edge AND the kick harness. There are a few games that don’t like this for very specific edge cases - for example Akumas raging demon in SFwhatever does not work unless this is set to off
SW4 = this is for mono/MVS stereo on the jamma edge, I’ve always left this “off” for mono.
LPF = this is the Low Pass Filter built into the 7374. Having more than one low pass filter in your video chain can result in a very minor loss of detail. Also be aware that the silkscreen is correct if you are using a jumper, but if you use the switch in the BOM the switch is a weird one and “off” on the switch is “on” for the LPF
SW4 = this is for mono/MVS stereo on the jamma edge, I’ve always left this “off” for mono.
LPF = this is the Low Pass Filter built into the 7374. Having more than one low pass filter in your video chain can result in a very minor loss of detail. Also be aware that the silkscreen is correct if you are using a jumper, but if you use the switch in the BOM the switch is a weird one and “off” on the switch is “on” for the LPF
Orakelschaf
Student
Thanks alot!
Has anyone had issues connecting a Minigun to a Retrotink 5x? I tried connecting mine with a retro-access "Genesis 2 RGB SCART cable with csync - 75 ohm multicore coax." The Tink showed no signal in RGB SCART mode before I powered the Minigun and the Naomi with Capcom IO on, but after I powered the game, the TV lost the Tink HDMI signal completely. The Minigun is in 75 ohm mode and LPF is set to off (which I think means its on). It's not connected to -5V. I connected the Minigun to my PVM with the same cable and it's been working fine. I also tried a different system with a different cable on the Tink afterwards, and there were no problems. I haven't updated the Tink firmware, I think it's still running 1.01 from the original early May 2021 shipment.
Was the NAOMI outputting 31KHz (480p) video? Please try again with 15KHz video.
Nope, 15KHz with the Tink and PVM.
GeorgeSpinner
Grand Master
I have used the minigun with the retrotink 5x without issue.
I have used it with MVS, CPS2, CPS1, TAITO F3.
I had no luck with midway open ice. I bought the retrotink 5x hoping to use its downscaling capability on the open ice PCB. It can't even sync with the open ice PCB.
Yeah... sync is hit or miss with a lot of systems. True of the OSSC and others as well. I've had some luck running the signal through a RGBS to component converter before going into my OSSC/RetroTink but even when it works it looks wonky (top of the screen is curved where the sync signal changes frequency).
Have a sync striker on the way, will see how that works for me.
component video will usually also do a basic "sync strip" then set impedence then add to green signal, so you may not find a difference, but worth a try. 'syncstrike' utilises a basic LM1881 which does a sync strip and converts whatever-sync to TTL sync.
i had one person who i sold a minigun to, who had problems with their tink5x. probably same type of problem (some miniscule out of standard range sync problem). i have a ivan stewart super off road jamma PCB which is at 15.7khz and nothing likes it (i mean NOTHING) except an OSSC v 1.5 - but damn it,, i want to play on a CRT (with my minigun), not a HDmi display
GeorgeSpinner
Grand Master
The frustrating part is that open ice syncs so easy with the ossc.
OSSC lacks downscaling.
I have a gbs-control as well (which supports downscaling) but I don't consider the gbs-control to be reliable. It's basically a hack and it's far from complete. It takes me 15-20 minutes to get the downscaling working properly, per power-on, since it does not save the important settings (screen position, phase, brightness) for this board. I have to fool it into syncing with the PCB anyway.
I only entered the blurb about Gbs-control to (hopefully) prevent someone from telling me I should try it. I've already more than tried it
Hum... my GBS-Control setup remembers the settings when I save them via the web interface. But I agree that it's a bit fiddly.
GeorgeSpinner
Grand Master
I will see if they've done an update since I last looked at it but I'd bet it does not save settings in the dev section. Some of the settings I need to adjust are in there.
Thanks for the info.
It has been said that the LPF labels are backwards when using a switch. This means that the LPF in ON when the switch indicates OFF and viceversa. Does this apply to the SYNC switch as well? Are we sending a TTL SYNC when the switch indicates 75 ohm SYNC? Please someone confirm. I don't want to damage my SCART equipment. Thanks.
