Region modifying American snes colour fix?

Howsit?

I have in the past modified a few pal consoles to be region free. These have been done by the old school way (switches) and tge early pal board (2 ppu chip).

I bought some supercic chips from BadAd_84 back when we were boys and i have finally gotten around to this. I was suss on the colour that would be output when an American console was switched to 50hz (ie b/w). I thought the fix would be to replace the "x1" crystal with the same one as a pal console (17.7xx vs 21.something). This was just fail as there was no image at all only sound and it had been slowed right down as in, almost under clocked rather than just a frequency change. I put the original crystal back in and it works fine allthough having 50hz in b/w UNLESS i force the tv to ntsc 3.358Mhz. Then i get colour.

I thought replacing this crystal was the key because
A/that is what you do for the later single chip board (well adding not swapping)
B/it is the crystal that is in pal consoles which net pal50 and pal60 which pal tvs are happy to do.

So has anybody successfully region modified (as in frequency) an American snes? No scart please as i am in australia.

 

You need to lift (pin 9? off the top of my head) on the video encoder. This is also set to gnd or +5v to change between modes, so you need to do that too when you swap the crystal.

From memory, YMMV.

Edit:

gnd for pal, 5v for ntsc. So measure it first to confirm its 5v currently

 

Thank you for that, pin 9 was no good though, lifted and ground had no video.

The video encoder is BA6592F...

edit found this

http://mikejmoffitt.com/BA6592F.pdf

Pin 19 seems to be the winner.

Thank you again

edit #2

Swapping that crystal causes the console to slow right down, would it be X1 I replace? (about to head off to work so may have try again tonight)

edit #3

Looks like I have to trace back and fid something attached to pin 14 (referring to test circuit on page 15). So in the end it *should* be GND pin 19 to lock into PAL and wire in my own 4.43Mhz oscillator for pin 14.

Maybe.....

 

Buttered toast.

I tried a 4 pin oscillator tonight on pin 14. It worked but the screen, at a guess lost sync as parts of the screen would go wavy. It would right itself then go wavy again, so i have to do up a shopping list and get the parts as per the schematic and try again. Not to bothered about this console as the case is the horrible green. But i am confident since it partially worked with the 4 pin oscillator.

 

Thinking about it, the clock signal is divided differently. So yeah, you probably want to do exactly what you attempted to get it working.

 

Cheers once i get the parts (there goes a couple of weeks...) i will report back. Shame it isn't as easy as a pal console. Oh well plenty of other stuff to do. I might even try this retrobrite lark!

I do have another us snes to do but it is a later single chip (the above is the first rev with the seperate sound box).

 

Single chip one is much easier to do, as part of the mod covers exactly what you are attempting to do (making sure you get the correct colorburst depending on which mode the supercic is in)

 

Yup got the parts and schematic for that one. To keep me amused (for 10 minutes) i have a heap of controllers to clean up anyway as well as other consoles.

Ordered the parts, had to get 68pF instead of 66pF and 82pF instead of 81pF caps, so hopefully that will be fine (the tolerances allow for it) if it is a little hazy I will source some trimming caps.

 

The parts came in, so I threw the circuit together. It all works fine.

50Hz



60Hz



Circuit in, bit messy. Next time I would add the NTSC/PAL switch onto the board. Alternate capacitors worked ok.



Schematic of pins 13-15 for colour fix



Now onto the switchless mod lol! At this stage I just had the 50/60Hz done via a switch.