SNES Mini Rgb mod

MtothaJ

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I have a SNES Mini incoming and am looking into whats the consensus here is on the best way to mod it for rgb.

The standard mod seems straight forward - connect rgb from the s-rgb chip to the av connector through 75ohm resistors and connect csync (will be using a cable wired for csync).

However I have a spare RGB amp kit from Broken - can anybody say whether its worth bypassing the stock SNES mini encoder and using that instead? since this is my only spare, i would expect a notable differenc3 if i am to go this way. In such a case I take it I don't necessery need the 75 ohm resistors on the rgb lines?

I also seen certain schematics where the rgb lines were connected to ground by a 75ohm resistor - kind of the same termination as in the pal snes cables - any views on this?

Any tips and comments welcome.
 

GohanX

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The only real reason to bypass it in that system is if you have the dreaded line in the middle of the screen. If you don't, just do the regular mod, you won't gain anything.
 

MtothaJ

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Thanks guys, in that case I will do the regular mod once my system arrives. I guess I can always revisit later on in the event of any problems. Will also look into putting in the power led and removing the tabs that stop one putting in the SF carts.
 

kuze

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Yeah just go for the regular mod.
 

leonk

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So there are actually 3 mods for the SNES mini. The "regular" mod that simply uses 75 ohm capacitors, the broken amp (which is actually out of NTSC spec as it uses 100 ohm resistors on output when NTSC impedance calls for 75 ohm) and the most recent edition (info on retro rgb) where the output was actually scoped to get correct impedance and voltage (same Ti amp using 75 ohm output resistors and 1.2k input resistors). No white line and actually a tad sharper than original method.

I've done all 3 installs and find the 3rd one as simple to do as original (if you got the components to build your own amp and feel comfortable with surface mount IC) and will now only offer this method to my customers. Read retro rgb site for more info.
 

MtothaJ

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Received my SNES Mini today and proceeded to doing the mod. I had my RGB wires + resistors as well as the LED+resistor+wires prepared beforehand and I would highly recommend to get these done ahead of time since this allows to concentrate on the actual mod and in any case there is plenty to do. Modding in progress:

2015-07-24 19.13.15.jpg

Apart from the standard RGB + cysnc reattachment, the other things that I did were:
- adding a power LED (basically followed this guide https://www.youtube.com/watch?v=ykiPLUwiKw4 with the only difference that I tapped 9V instead of 5V, with the appropriate resistor ofc)
- removing the tabs in the cartridge slot that prevent one from inserting a SF / PAL SNES cart
- removed the power connector off the US power supply and soldered it on to a Hama universal 1500ma power supply (pretty weird non standard connector)
- had to change the fuse (stock one was either dead on arrival or maybe I fcuked it up doing the mod)
- gave the case a good wash

As for the final effect - definitely worth the hassle of getting a SNES Mini and doing the mod. The image is so much sharper than on the standard 2 PPU model. As for the mod it is pretty straightforward, the most difficult part is soldering to the chip pins since these are pretty small but apart form that it really is just a 'join the dots' type of exercise.
 
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SmokeMonster

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Great looking work.

I have an RGB modded Mini and a standard SNES (SHVC launch model) and Super Famicom (SHVC too). I don't notice any additional sharpness from the mini, but I do notice that its color are crushed and the contrast is blown out, and it's incompatible with some games (Super Ghouls 'N Ghosts is unplayable). I also don't like the way it sounds. I think that people confuse sharpness with contrast, or maybe my SNES & SFC look better than most because they've been recapped.

To me the Mini is an SNES on a chip emulator.
 

MuppeT

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Great looking work.

I have an RGB modded Mini and a standard SNES (SHVC launch model) and Super Famicom (SHVC too). I don't notice any additional sharpness from the mini, but I do notice that its color are crushed and the contrast is blown out, and it's incompatible with some games (Super Ghouls 'N Ghosts is unplayable). I also don't like the way it sounds. I think that people confuse sharpness with contrast, or maybe my SNES & SFC look better than most because they've been recapped.

To me the Mini is an SNES on a chip emulator.


Are you running the RGB moded snes mini on the regular cables ? Because the difference is quite amazing actually..
 

SmokeMonster

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I'm using retroconsoleaccessories Scart RGB cable. The mini at first glance probably looks better via composite, because its high contrast will seem like improved sharpness and help offset the composite blurriness.
 

SmokeMonster

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Mine boots with glitches and the sprites are all wrong. That is with the actual SG&G cart. I just looked for more info and apparently there are different revisions of the mini, some of which don't support Super G&G and Pocky and Rocky. There is some good info on the revisions here.
 

GohanX

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I bet his mini has the wrong resistor values on the mod (or are missing entirely.)
 

kuze

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Mine boots with glitches and the sprites are all wrong. That is with the actual SG&G cart. I just looked for more info and apparently there are different revisions of the mini, some of which don't support Super G&G and Pocky and Rocky. There is some good info on the revisions here.

That guy seems to be talking about the 1chip not the mini?
 

SmokeMonster

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Here is the thread I should have linked. After looking more in to this, it looks like the majority of mini actually will boot G&G, so mine is one of the few that doesn't. I also don't like my 1chip SNES either though, so it could be a personal bias.

I bet his mini has the wrong resistor values on the mod (or are missing entirely.)
This was the process I followed. I could redo it with a proper RGB amp, but I'm extremely satisfied with my SHVC SNES and SHVC Super Famicom so there is really no point.
 
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MtothaJ

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Was a bit surprised about the comment on SGNG being unplayable as yesterday I played through the first three levels of Chomakaimura and did not notice a thing wrong. Today I did some testing firing up the Super Ghouls and Ghosts (love those Prince style Ankh symbols instead of crosses on the tombstones - Nintendo really is watching out for us with their censorship) and Alladin, which is supposed to have the most apparent glitching. Basically all I found is that for all three of these games, there would be on occasion some white flashing in parts of the topmost line of the screen. I could only see this line when I entered underscan mode on the BVM - having my monitor set up for multiple systems I guess it just got cut off under the standard settings. In any case this is something so trivial and minor I would not even give it a second thought.
As for the picture being overly bright / saturated using the standard mod - there is some truth in that, but frankly this is not really a big deal for me and in any case solutions to rectify this brightness exist. Comparing to a 2PPU machine one other aspect I noticed is how much clearer the picture is - maybe its due to using Cvideo for sync on the 2PPU machine, but there I got pretty bad dot crawl and diagonal wavy patterns on bright backgrounds e.g. orange title screen on Super Mario All Stars. On SNES Mini this problem is non existent (using csync).
Don't have much experience with the 1CHIP - in EU getting one doesn't really make much sense since to mod it for 60hz you have the additional complication of needing to get a NTSC 21.47727 Mhz crystal / quartz oscillator.
 

MtothaJ

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Guys, just wondering if there is any trick to be able to see the traces on the underside of tje Snes mini board? Or perhaps some schematic exists to show where they go? Specifically I am interested in the trace suppling +5v to the av connector pin 10. The soldermask is so thick one cant see shit.
 

GohanX

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Use a multimeter to check for continuity with a known 5v source such as the voltage regulator.
 

MtothaJ

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Use a multimeter to check for continuity with a known 5v source such as the voltage regulator.

Maybe I am not getting it, but I figure using a multimeter will simply tell me the two points are ultimately connected however will provide no information where the particular trace is running on the board.
 

GohanX

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Why do you need to know where the trace goes?
 

GohanX

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Ah, I see. Then my suggestion really isn't very helpful!
 

MtothaJ

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Ah, I see. Then my suggestion really isn't very helpful!

What I will probably do is just desolder the whole Multiout connector, cut the connector leg for the +5V pin going through the via and isolate the via with some electric tape and then connect the power wire to the connector pin directly from the back (much like is the case with the RGB lines when installing Broken's PCE RGB Amp). Was just hoping there might be an easier / quicker way to do this.
 

leonk

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Tim W of NESRGB fame had a scart cable with amp in it just for that cause. He might still have it for sale.
 

MtothaJ

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Tim W of NESRGB fame had a scart cable with amp in it just for that cause. He might still have it for sale.

Did some more thinking on this I instead of modding the console I will just mod one of my scart switches with a 9 or 12V PSU and a DPDT switch for pins 8 and 16. One side of the switch - simple passthrough, the other side - 9 / 12 V going to Pin 8 with the appropriate resistor (e.g. 330ohm) to pin 16. Simpler in the long run since I won't have to deal with this bullshit on a console by console basis going forward.
 
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