This question regard modding an SNES ver. 2 to have RGB out. On portables of doom, there is a mod which calls for a 200 microfarad capacitor between each rgb input and the output. On GamesX.com, there is a somewhat different mod involving <i>pico</i>farad capacitors and a couple resistors.
My question is this: has anyone done these and which one works (or works the best).
Also, it seems that the diagram on GamesX seems confusing and I am wondering if anyone has a better version of it.
SNES RGB Amplifier
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Ok, so nobody answered my post, so I checked the stuff out on my own. I tested the variations using a SNES version 2 and a PSOne screen with the led mod. The "amplifier" shown on GamesX is not very good as it actually makes the screen darker than what you might normally see. The reason for this is the voltage divider - adding any voltage to any (or all) of the RGB lines seems to degrade the signal (possibly by masking it in DC) and making it less strong.
As for the POD mod, in which a capacitor is placed between the SNES output and the screen, it didn't do anything to the image. I am guessing this is included to keep any DC transients away from the screen, but I don't know how necessary it is. Also, running an "interference filtering" capacitor from the RGB output to ground as described on the GamesX page also did not affect the signal at all.
So, from what I have seen so far, the best RGB picture into the PSOne screen can be achived by just connecting the RGB output from the SNES to the RGB input on the screen. DC/inteference filtering capacitors can be added, but they may not be necessary.
As for the POD mod, in which a capacitor is placed between the SNES output and the screen, it didn't do anything to the image. I am guessing this is included to keep any DC transients away from the screen, but I don't know how necessary it is. Also, running an "interference filtering" capacitor from the RGB output to ground as described on the GamesX page also did not affect the signal at all.
So, from what I have seen so far, the best RGB picture into the PSOne screen can be achived by just connecting the RGB output from the SNES to the RGB input on the screen. DC/inteference filtering capacitors can be added, but they may not be necessary.
I feel I must comment on this. My SNESp Mk. II uses RGB with a PSOne screen and a model one board--and uses capacitors. However my image gets dark after about 30 minutes of playing.
I have a hunch that this may be due to the capacitors "saturating" with signal and distorting the video feed after they charge up over time.
This is where I connect with this thread. I wonder if bypassing the capacitors totally will fix this problem?
Give me your input on this, because this problem is annoying me lately.
I have a hunch that this may be due to the capacitors "saturating" with signal and distorting the video feed after they charge up over time.
This is where I connect with this thread. I wonder if bypassing the capacitors totally will fix this problem?
Give me your input on this, because this problem is annoying me lately.
If all else fails, take it apart!
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nos_slived
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Well, I have hooked up my SNES to RGB and, just in case, I used both a capactor in the RGB line and one from the RGB line to the ground. Yesterday I ran it off of batteries to see how much playing time I would get (3.5 hours, but that is without a controller nor me playing, so I would guess I'll get 3 hours playing normally, conservatively speaking).
Anyway, I never had any problem with the screen getting too dark during the whole time I played, so I doubt it is a problem inherent with all capacitors. Now, it could be the ones you are using, but I am not sure. Based on my experience, the screen will get darker if you add too much dc bias to the signal (it essentially drowns out the signal, I think). If you have a capacitor, it should block this.
However, you are using a version 1 board, and from what I can tell the RGB mod on gamesX essentially recreates the circuit from the model 1 board. So, since I found the screen got darker when I tried their mod, it could be the internal RGB circuitry in the SNES is causing problems. There is no real way to fix this without permanently changing the SNES' circuit board. But if you want to what I would do is get your RGB off of the chip as described on gamesX, and then cutting through any circuit traces connecting to those pins on the chip so the internal circuitry between the chip and the SNES board is disconnected. This is potentially dangerous (and soldering onto that tiny chip isn't easy), but it might fix your problem.
Anyway, I never had any problem with the screen getting too dark during the whole time I played, so I doubt it is a problem inherent with all capacitors. Now, it could be the ones you are using, but I am not sure. Based on my experience, the screen will get darker if you add too much dc bias to the signal (it essentially drowns out the signal, I think). If you have a capacitor, it should block this.
However, you are using a version 1 board, and from what I can tell the RGB mod on gamesX essentially recreates the circuit from the model 1 board. So, since I found the screen got darker when I tried their mod, it could be the internal RGB circuitry in the SNES is causing problems. There is no real way to fix this without permanently changing the SNES' circuit board. But if you want to what I would do is get your RGB off of the chip as described on gamesX, and then cutting through any circuit traces connecting to those pins on the chip so the internal circuitry between the chip and the SNES board is disconnected. This is potentially dangerous (and soldering onto that tiny chip isn't easy), but it might fix your problem.