Weird Megadrive 2 motherboard

[angel177]

ok lads I need a little help and you gents all seem to know your stuff, I just moved to canada and want to convert my PAL MD2 to display in 60hz, mmmonkeys guide seemed straightforward...till i opened up the case and the motherboard looks NOTHING like it should, it has no JP3, and the C51 trace is in the middle I'll pop some pics underneath this post, any help would be greatly appriciated.

[angel177]

[IMG][/IMG]

[InsaneDavid]

There were a few different revisions of both the Genesis 1 / Mega Drive 1 and Genesis 2 / Mega Drive 2 motherboards. The 315-XXXX chip is the key. Pin 107 of this chip runs to either a +5v plain for USA (and EUR in 50Hz mode) or a GND plain for JPN. Pin 46 of the same chip runs to either GND for 50Hz or +5v for 60Hz. This should apply to all Genesis 2 / Mega Drive 2 systems (including the JVC X'Eye which uses the same chipset) but as I don't have your specific board in front of me, I can't confirm this with 100% certainty.

You have to isolate the hard connection and replace it with a SPDT switch, one side connected to +5v and the other to GND. Of course one switch is needed for pin 107 and another for pin 46.

Nearly all tutorials use the above method but attempt to generalize things by telling you specific pins to look for. The problem is with so many board revisions your system will often be different than what is shown. (mmmonkey has some great tutorials though and uses the most common versions of the boards - that I've come across anyway) Even though different tutorials may tell you to connect at different points, everything runs back to pins 107 and 46 of 315-XXXX. Once you understand this you can figure out good places to break and make both connections. Pins 107 and 46 of 315-XXXX are the source, regardless of where you might slice and pick them up, it's all the same.

[FABombjoy]

Do you just want 60Hz, or 60Hz NTSC?

[angel177]

60hz ntsc, but just 60 hz would be great since alli want is to be able to play my collection

[evildragon]

60hz ntsc, but just 60 hz would be great since alli want is to be able to play my collection

Unless you have RGB, just 60Hz will be in black and white, and not color.

You'd need to modify the video output to do NTSC...

[angel177]

I have a rgb converter so i'm not to worried bout that aspect...