Today I bought an Asian PAL-B megadeive (srica trading Malaysia).
The warrenty stickers were stabbed through and it had the wrong screws in it so I cracked it open to see why.
This is what I found:
(http://i189.photobucket.com/albums/z234/phreak97/4173F6A1-C66B-4807-BA46-F08D8D820C1B-372-0000001E35C11525.jpg)
The language has been changed and this little pcb added, it's not doing anything to the language, merely tapping power and ground from the solder points.
The ic is a HA17555 and the transistor(?) is labelled C828.
I'm yet to plug it all in an test it, but I can't think what this could possibly do..
Any ideas?
That's pretty odd. A 555 timer basically just pulses. If my expansion port pinout (http://www.gamesx.com/cartouts/gennyport.htm) is correct (and that's iffy) then this mod appears to be connected to pin B19, which is A16 (address line 16).
Anyone care to guess at why?
Yeah thats what i thought..
The system seems to work fine the way it was (japanese language 50hz, mod in place).
I did a little experimenting, i kept the two blue wires on 5v and gnd and changed the language back to english. It then wouldnt boot, no license screen or anything, Lifted the red wire and it booted.
I'm wondering if maybe it gets around the 50/60 lockout on some carts.. What are some protected games? Ill give it a shot
Ahh, that's interesting. Sounds like it boots into one region and then shifts into another later. Bypassing the region check (which occurs at boot) and then shifting to the English language version once the code starts running.
But why A16?
It doesnt change language, i did that manually and somehow that conflicted with the signal from the 555.
And yeah i have no idea, A16 doesnt make sense..
I ended up disconnecting the mod and setting the console back to original, but if anyone knows of any 50/60 locked japanese games ill do some more testing
Not sure what you mean by 50/60 locked Japanese games, but if I remember correctly Monster World IV is JP60 / PAL50 only. (ie: not US60)
I mean games which wont run at all in 50Hz, do they exist?