Have gotten a Japanese mega drive one console and intended to carry out the 50/60hz and Lang mod on it. Upon opening it up I notice that there had been a mod carried out already, where the JP pots are located for the 50/60hz & Lang mod there was a wire solder to the right hand pot of JP3 which ran to one of the connections of the reset button, the traces between the pots of JP 4 and 1 had also been cut, on a PAL system I believe it's usually JP 2&3 that have traces connecting the pots but on this console Japanese console it is 1&4 for some reason? Anyway I'm not 100% sure what this mod is!?, with a game running if I press and hold the reset button then the game obviously reset but if i still hold the reset button then the game runs at 60hz if I release the reset button it reverts back to 50hz, it appears to be normal running at 50hz even though it is a Japanese console. Any ideas? PS. is it possible to carry out the usual 50/60hz mod on a Japanese system, as the traces link some of the pots on the JP's appear to be different from the guides I have seen about!?
I have actually unsoldered the wire now...but below is a pic to show where the wire was soldered to on the undersider. Notice the capacitor circled in the red, only one leg is soldered to the PCB, the other leg with the blob of solder on isnt attached, and the row of what should be 4 components (transitors?) just the capacitors leg with the blob of solder on the end one if missing so only 3 solder to the actual pcb id marking on the top side of the pcb are SEGA IC BDM5 VA4 837-7138 and model number on the case is HAA-2510
*EDIT* I have retained what I have already said below That console has been modded to play 50Hz. Notice the 2 pin oscillator? The small silver job slightly above the capacitor you mentioned? Maybe this was modded for the Asian (not Japanese) market as they run 50Hz. I have seen this before, where they mod a Japanese console and actually add an RF module and attach it to the heat sink. The capacitor there is maybe for that. I think they added the reset button trick so when the console is turned on, you hold down reset (for those games that do that check) and release to play the game happily in 50Hz. I had a repair to do similar to this, not so long ago (took pics can upload if keen). Via composite I found the picture to be off colour wise, white was a blue-ish white. It was a Japanese console modified for 50Hz with RF module. I noticed the there was a mystery resistor there, removed one leg and the picture came back correct. I fully removed the RF module and restored the console back to Japanese standard with some trace repairs. Original post Yes absolutely you can mod a Japanese Mega Drive. If you haven't seen a guide before, it doesn't matter as the theory is the same for all. It is best use a multi-meter though and suss out (once you have cut the tracks) which pair goes to which pair. There will be 4 pairs- GND x 2 +5v x 2 Language x 2 Video Frequency (ie 50/60Hz) x 2 That is why JP2/3 is PAL (as you have mentioned), so JP2 gets +5v for English and JP3 is Ground for 50Hz. Japanese has JP1 gets Ground for Japanese and JP4 gets +5v for 60Hz. On the dead side of these points (ie not gnd or +5v) JP1 and JP2 are linked, JP3 and JP4 are linked. You can confirm this with a multimeter. Finding ground is easy (outside edge of mainboard is ground), +5v you can test from a +ve of a cap or the voltage reg (looking at writing on regulator it is the right one). Then the other set of 2 will be linked which is the Language and 50/60Hz). If you are going the switch method, could I recommend the single switch mod? Take a 3 position switch and have between Japan/USA/PAL http://mdpal60.net/wiki/megadrive/regionmod/start *Ignore if you are using RGB* Also as you may know, going from 50/60Hz via composite you will get a b/w picture, so you will need to add an oscillator to "lock" the video encoder. I use a 4.433619Mhz oscillator (as per data sheet) so we get PAL50(Hz) or PAL60(Hz) which *most Tv's are happy with. You can also use the boards oscillator and via the switch add an additional oscillator for, in the Japanese console, 50Hz duties. Bloody hell I hope that makes sense....so bloody tired.
Thanks for the info, noticed there is a capacitor in place on JP 2, i take it it is safe to remove that?
Cool thanks, whats the deal with that capacitor i circled? OK, on closer inspect it would appear all traces between the JP have been cut, even though there in not traces between JP 2 & 3, a blade has still been taken to the gap between the 2 pots!!! Is this mod still salvageable seeings as this has happened?? Im going to remove the capacitor and remove all solder from the pots, whilst a await a reply
Please stop calling them pots. Pot = potentiometer. You are talking about either pads or the legs of parts from the other side of the board.
Yes this is indeed what i think this console was modded for as it did have a RF module inside that i unsoldered and removed. So am i safe to remove oscillator and capacitor as i will be using a Scart cable, also if you could upload those images to ad me please. Regarding all traces (and non traces) that have been cut between the pads of JP's, 1,2,3 and 4 do i need to add wires between certain jumps again so they are connected or wont it matter? Ok i have removed the capacitor and all the solder from the JP's, as you can see all gaps between the JP pads were cut regardless if they were joined or not (not sure what this was in ad off). But have noticed that JP's 1 & 4 appeared to be the ones that were linked not 2&3 like a PAL system not sure what this means or if the JP are different in regards to whats 5V, GND, PAL or NTSC, but i thought i read that ALL mega drives JP's were the same doesnt matter that postition thet are in?
Using my awesome paint skillz, here is how the region switch works. So you can see why Japanese consoles have 1 and 4 connected (language=japanese, frequency=60hz), PAL have 2 and 3 connected (language=english, frequency=50hz), USA have 2 and 4 connected (language=english, frequency=60hz). You can also see why adding a switch between these you can select whatever region you like.
Thanks for the awesome diagram!! Have a question would should happen if i dont have any switches attached to any of the JPs and the traces cut? As i have just plugged it in and all im getting is a red display, any suggestions?
Hmm that's weird, if you don't have any connections done it should boot in American mode as the pins the "JP" points are connected too pull themselves high (ie +5v). As to red display, make sure you have knocked anything out of whack...
Then it's a rest of Asia or modded console. As said before Sega didn't install RF modules for Japan. Well two switches gives two maximum control. If you're fine with minor case mods. It lets English/Japanese and 50hz/60hz be independently switched while running. The JP's affect Master System mode also, as well as change which region Mega CD drive will start. (an unhacked Mega CD BIOS checks the console's region)
I have removed the oscillator from the underside of the PCB should i also be removing the capacitor i circled in the red on my picture a few posts above if im going to be using a Scart cable with this console and not a RF lead, is it that thats causing a red screen?
Have you tried a raw sync Scart cable? Some devices that use sync from composite video for their RGB input won't work without the color subcarrier.
Im not sure that is the answer as it was working ok before i removed the wire going from JP 3 to the reset terminal and the capacitor between the pads on JP2, this capacitor would cause me to lose display would it?
You are booting it with a game, right? Yes, the jumpers are for different regions - hope you understand that now from the diagram What jumper is shorted determines which mode it's in, naturally. I have a Japanese console with a similar mod - as was mentioned, it had an RF unit and the mod was to get colour out of that on a PAL TV.
Oh well, I suppose you have a point Japanese is what people call them. It's like using DVD for Wii discs contrary to what Nintendo PR would have one believe.
Wii doesnt use DVD, it uses Nintendo Optical Disc format. They do not pay for DVD licensing fees. If it was actually DVD - they would have been sued by now. The later Wii drives also cant read DVD at all, but can read original discs. The modchips exploit a mode that wasnt actually used in the drive (probably added for people to play DVD movies, but was never used).
