MS8-29FSG Partlist and neckboard schematics - Super sharpness circuit

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Nebula
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MS8-29FSG Partlist and neckboard schematics - Super sharpness circuit

Post by Nebula »

Hi!

I found on the net some different flavours of the Nanao MS8 chassis and, when I look at what's was uploaded to the wiki page here for it, I see that only the schematics of the main PCB was present, in addition to a short japanese manual.

I uploaded two files to this page: https://wiki.arcadeotaku.com/w/Nanao_MS8-29 covering the partlist of the main PCB (only) taken from a Daytona USA manual, and another file with the schematics of the neckboard pcb and the components installed it, that was previously missing in the wiki.


Regarding last one, I can identify the section of the circuit in the neckboard related to the "Super Sharpness" (S/S) mode present in MS8 Chassis:

Image

It consist in 2 capacitors, 1diode, 1 resistor and 1 DTD transistor for each color, and the incoming signal S/S in the connector comes from the remote-control board where a switch is located to provide +12V when activate it, or GND when not active: (remote board schematics taken from MS9 because this is not available for MS8, but MS9 remote board also has the footprint for that switch):

Image

but, what's the purpose of activating this? I mean, what's the effect on the image and is it recommended? What's the inner working of that portion of the circuit and the effect on the RGB signals sent to the CRT cathodes?


Apart from that, I realized that MS9 neckboard are also provided with this "Super Sharpness" circuit but unpopulated:

Image


Was this probably discarded by Nanao in the final stages of design of MS9 chassis? Could populating those components to try it in MS9 cause some damage on the rest of the circuit?

Thanks
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Re: MS8-29FSG Partlist and neckboard schematics - Super sharpness circuit

Post by thegreathopper »

I used to have a MS8 with the button, I worked out it affected sharpness but preferred it off - it made everything too pixelated for my eyes.

Forgot to add this was a MS8-26 not a 29.
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Re: MS8-29FSG Partlist and neckboard schematics - Super sharpness circuit

Post by cools »

Off
IMG_20211015_185552.jpg
On
IMG_20211015_185556.jpg
It's subtle. The whole image shifts a quarter/half pixel to the left, and edges are stronger. It also distorts very high contrast areas as shown, the text is crisper but one edge is overly bright and blooms.

I have it switched off.
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Re: MS8-29FSG Partlist and neckboard schematics - Super sharpness circuit

Post by nem »

It looks terrible, there's a reason why it wasn't included on the MS9.
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Re: MS8-29FSG Partlist and neckboard schematics - Super sharpness circuit

Post by Nebula »

Looks like there are consensus in this topic :awe:

I was just curious to see how it affects in MS9, but seeing your feedback I doubt if it really worths it. Anyway, first I need to ensure there would be no risk to damage other components.


I also would like to know the reason or the transformation behind this, regarding color signal shape. Does it affects the signal amplitude? or may make signal sharper instead more continuous?


Rest of the components in the neckboard are pretty the same between MS8 and MS9, with the exception of G1 signal that is tied to GND in MS9 while MS8 sets a negative voltage for it.
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Re: MS8-29FSG Partlist and neckboard schematics - Super sharpness circuit

Post by nem »

Nebula wrote: October 15th, 2021, 7:46 pmRest of the components in the neckboard are pretty the same between MS8 and MS9, with the exception of G1 signal that is tied to GND in MS9 while MS8 sets a negative voltage for it.
Like the SS switch, the pads are there for a negative G1 voltage.

http://mikejmoffitt.com/pages/ms9-hax/#g1mod

MS8-26 is the same, G1 is tied to GND. Again, the pads are there, but unlike the MS9, the flyback on the MS8-26 generates a measly -3V voltage IIRC. Sad. If you ever wondered why the MS8-25 and -29 blow the pants of a -26 in sharpness, there's your reason.
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Re: MS8-29FSG Partlist and neckboard schematics - Super sharpness circuit

Post by Nebula »

nem wrote: October 16th, 2021, 12:32 pm
Nebula wrote: October 15th, 2021, 7:46 pmRest of the components in the neckboard are pretty the same between MS8 and MS9, with the exception of G1 signal that is tied to GND in MS9 while MS8 sets a negative voltage for it.
Like the SS switch, the pads are there for a negative G1 voltage.

http://mikejmoffitt.com/pages/ms9-hax/#g1mod

Yeah, I was aware of that mod made by Hatsune Mike, and I'm still pending to test it in one of my MS9 (god bless its flyback that already supplies the proper voltage for it :D)

nem wrote: October 16th, 2021, 12:32 pm MS8-26 is the same, G1 is tied to GND. Again, the pads are there, but unlike the MS9, the flyback on the MS8-26 generates a measly -3V voltage IIRC. Sad. If you ever wondered why the MS8-25 and -29 blow the pants of a -26 in sharpness, there's your reason.
I didn't know that MS8-26 is different than -25 and -29 in terms of neckboard. Sad to hear that about the flyback negative voltage, maybe putting some hacky winding around flyback core manually will power you up a negative voltage to use in G1 anode. There is a thread in shmups forum with experiments from different people doing this in a wide different monitors and CRTs.
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