Hello! First post so hope I'm in the right place. I recently recapped a Nanao MS9 and NVS-4000 PSU. Everything went great. I was having an issue BEFORE the recap where the screen will shake/expand/bloom on bright screens (metal slug intro/samurai shodown fights). The issue still remains after recap. I have checked psu output and have solid 5v. I have also checked b+ voltage and I'm at 74.8v which I believe is spot on. Is there anything else I can do? The issue does get better when lowering rgb gains and contrast/brightness and will be non existent when screen is dim. Anyway thanks all!
- Thread starter JScott03
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- nanao sega astro city toshiba
you'll probably want to adjust the gain (sometimes called "Screen") on your flyback.
I usually follow the method described here for adjusting the screen and brightness: https://wiki.arcadeotaku.com/w/How_to_Correctly_Set_Up_Monitor_Colours_and_Brightness
I usually follow the method described here for adjusting the screen and brightness: https://wiki.arcadeotaku.com/w/How_to_Correctly_Set_Up_Monitor_Colours_and_Brightness
Thanks for the reply. You know I actually went through this exact guide last night. My finished image was great for a dark room and didn't have the issue but too dim for what I'd say is good for a lit room. Adjusting the contrast/brightness any higher after these steps brought the issue back. Maybe I'm spoiled by some of my higher end sony crts and the nanao just can't get bright like I want.. I'll try these steps again tonight!
Metal Slug
Enthusiast
I think most MS9s I have seen have some bloom on an all white/bright screen. When you did your recap, did you replace the large filter cap (the 1000uf 200v at C911?) I have read about failing filter caps sometimes causing problems like this. Most cap kits sold do not include filter caps.
Yes I did make sure to also replace the filter caps as well as neckboard cap and daughter control board. So not an old cap in the whole machine which about killed me haha. It would be nice to confirm that most or all ms9s have this issue. If that's the case I'll happily keep it brighter and for the games that have it bad I'll just turn it down. Hopefully I can fix it though. Thanks!
Very true! I'll keep that in mind.
There's a pot called ABL on the chassis, it's short for Automatic Brightness Limiter. You can try adjusting it to see if it makes any difference.
But yeah, the screen expanding on bright images will always happen to some extent on a MS9.
But yeah, the screen expanding on bright images will always happen to some extent on a MS9.
Just wanted to give an update.. after spending a lot of time messing with all the pots I was able to get it looking great. Thanks everyone for the advice and confirming that these monitors all have some sort of bloom.. that calmed my ocd a bit haha. Thanks again!
This thing, blooming on white screens is common to some degree across every single CRT.
Sony solved this on their Pro and Broadcast CRTs (PVMs and BVMs) with a “beam current feedback” circuit.
I suspect that despite the fancy marketing name this was probably something like referencing the earth on the color transistors to negative instead of ground.
anyhoo the point is that only PVM or BVM can eliminate this problem entirely. And probably the equivalent from Bhaco andJVC. for everything else it’s always going to be there to some degree.
So by doing what you’ve done (contrast and G2) you’ll get the best picture that it’s possible to get.
i lust after an MS9 - one day, one day!
Sony solved this on their Pro and Broadcast CRTs (PVMs and BVMs) with a “beam current feedback” circuit.
I suspect that despite the fancy marketing name this was probably something like referencing the earth on the color transistors to negative instead of ground.
anyhoo the point is that only PVM or BVM can eliminate this problem entirely. And probably the equivalent from Bhaco andJVC. for everything else it’s always going to be there to some degree.
So by doing what you’ve done (contrast and G2) you’ll get the best picture that it’s possible to get.
i lust after an MS9 - one day, one day!
