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Nanao MS9-29 enhancement hacks

Tried these 2 mods on a MS9-29T chassis.

So far so good :)

The G1 mod is a nice improvement to sharpness/scanlines in 15khz, really worth it.

The 31khz mod is a nice "free" upgrade to the chassis, although it's not perfect, especially on geometry / "rollover" on edge. (I have never tried 24khz mode.)
Tested with Exa-Arcadia and Naomi games, it looks quite nice from my point of view.
B+ set to 119v for now (for the "24/31khz mode"). Set to 76v for 15khz.


@Hatsune Mike : thank you for all of these informations :)
Do you have more informations to share about "Some slightly more complex modification will be needed to do higher order corrections to adjust for the edges in particular." ? Thanks :)
 
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The diode I used for the G1 mod is P0102BL 5AA4 STMicroelectronics.

here is a mouser link:
https://www.mouser.fr/ProductDetail/STMicroelectronics/P0102BL-5AA4?qs=A414Geqrv0Ww5gGZ8ajZVA==

EDIT: don't use this diode, it's not the correct pinout...
(the G1 mod works [fine btw, tested for 50 hours+], but there's no protection if something goes wrong... as the diode doesn't guide the electrical flow on the "good side".)

Use these instead:
https://www.mouser.fr/ProductDetail/771-BAT54C235
https://www.mouser.fr/ProductDetail...nts-MCC/BAS21C-TP?qs=KFo7JewZbUHDvl7XOTRtIA==
 
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zombiz said:
Tried these 2 mods on a MS9-29T chassis.

So far so good :)

The G1 mod is a nice improvement to sharpness/scanlines in 15khz, really worth it.

The 31khz mod is a nice "free" upgrade to the chassis, although it's not perfect, especially on geometry / "rollover" on edge. (I have never tried 24khz mode.)
Tested with Exa-Arcadia and Naomi games, it looks quite nice from my point of view.
B+ set to 119v for now (for the "24/31khz mode"). Set to 76v for 15khz.


@Hatsune Mike : thank you for all of these informations :)
Do you have more informations to share about "Some slightly more complex modification will be needed to do higher order corrections to adjust for the edges in particular." ? Thanks :)
Click to expand...
Glad you are getting good results from it.

As for the 31khz improvements, I don't plan on working on it any further - in short it seems like adjusting S-capacitors to fix the edges will result in further "tucking in" of the width, and the non-linear appearance may still have problems. This is outside of my area of proper understanding, as analog electronics is not my forte.
 
Did my second mod today on a Rev. D "05A00585D1' MS9 chassis and the results are mind blowing!
On a rev. C chassis, the results where really good, but on a this rev D the results are out of this world! I have never seen a image as sharp and vivid. It’s almost too sharp (if that’s possible…)
The only variable was the chassis. I used the same cab with the same game and same wiring etc. Both chassis had been recaped and serviced by me.

Is a Rev D chassis a better candidate for the G1 mod @Hatsune Mike ?
 
For reference for the 31khz mod: tried to swap s-caps (c519 with C531 and vice-versa ; original caps found on the chassis) on another chassis (MS9-29NDR23W) = black screen / protection mode. (B+ dropping)
I tried it to have a (very ?) low capacitance for the 31khz mode… but it’s too low.

So reverted back to values advised by HastuneMike.
 
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A few pics of the 31khz mode:
ED89D4D2-6348-40E5-A80A-B57A85975B76.jpeg


EFAB2031-35C3-41BD-A3C3-31241E366F61.jpeg


91957BD4-6F6C-42D1-9E66-3E394206E70B.jpeg


5D526885-3A15-403E-8F06-2DBDBB21AC4D.jpeg


DDEB91F9-A03A-4742-B116-547935FA148E.jpeg


D6A8F276-D99D-4752-9D4D-9C6895405283.jpeg
 
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Aka To Blue Type R (Exa-Arcadia)
31khz

The other one is Touhou Perfect Sakura Fantastica (Exa-Arcadia ; 31khz)

Side note: tried them in 15khz 480i (output from an Extron VSC 700) on the same chassis... colors are (much) more "vivid" on the "31khz mode" than in 480i
 
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G1 negative voltage mod looks great, though possibly too sharp for close viewing. I only modded one of my MS9 monitors though, left the other stock. When your face is that close to such a large screen, the softness of an unmodified chassis image is also really nice to look at. It really looks better when you're slightly further away. I wonder if thats why negative voltage to G1 was never fully implemented on MS9?
Anyway completely personal preference of course. Great article / website. The tuning and maintenance tips alone are totally worth it. These screens have never looked better.
 
narf said:
G1 negative voltage mod looks great, though possibly too sharp for close viewing. I only modded one of my MS9 monitors though, left the other stock. When your face is that close to such a large screen, the softness of an unmodified chassis image is also really nice to look at. It really looks better when you're slightly further away. I wonder if thats why negative voltage to G1 was never fully implemented on MS9?
Anyway completely personal preference of course. Great article / website. The tuning and maintenance tips alone are totally worth it. These screens have never looked better.
Click to expand...
You can easily adjust the focus on your flyback to soften it up to your preference.
The G1 mod gives you a larger degree of sharpness, but you can still adjust it.
 
Hatsune Mike said:
Worth reiterating that this is a restore of a circuit that already existed, and was like this on the MS8-29. It is already "normal" for this tube to be sharp that way.
Click to expand...
only on the first revision of MS9 has the circuit. subsequent revisions its removed. One of my chassis has the full circuit, the other just the position for the cap. It's entirely possible it was left over from MS8 which they obviously re-used used as the basis for the MS9 so not sure its normal if it were never used and then removed.
 
narf said:
only on the first revision of MS9 has the circuit. subsequent revisions its removed. One of my chassis has the full circuit, the other just the position for the cap. It's entirely possible it was left over from MS8 which they obviously re-used used as the basis for the MS9 so not sure its normal if it were never used and then removed.
Click to expand...
The circuit is there except for the final trace on later revisions.
 
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