Asian Megadrive

[Vertigo]

I don't know why.
Where should I start?

[kendrick]

I'm almost tempted to think that you're posting this just to have a laugh at the expense of Lawrence's hairline, but you're usually on the level...

I'd start with the PCB resting on the bottom half of the shell, with power connected and the power switch on. Then I'd look for the 5V+ on all the necessary chips (the Z80, the 68000, the Sony video chip, etc.) The lack of power on one or two of those might indicate a short or a cut trace. Lack of power at all the chips might indicate a more serious problem, like a burned out 7805 regulator. But assuming that you've done all the usual troubleshooting (swap power supplies, swap cartridges, swap video cables, etc) then this is the next step.

Oh yes, is this a Mark I or Mark II Megadrive? I've only ever brought Mark I units back from the dead. Mark II and Genesis 3 units tend to fail spectactularly when they do fail. Good luck.

-KKC, who can't find his logic probe and so must make do with a bad multimeter..

[Vertigo]

Heh, yes, I am on the level.
I haven't checked for voltages on the chips yet but will do later. I've done the usual hardware checks first yeh.
It's a Mark 1 system btw. Reason I want to resurrect this one is because it's nicer looking than a PAL one and that it has the bigger cart slot so I don't have to take the lid off every time I want to play a JP cartridge. It has no switches fitted yet, I'm going to get it working before I put those one.
I've heard talk of fuses going, which cause this sort of problem. Does this only apply to the SNES? I can't find anything that matches a fuse description (small black square) on the board.
Mine also has a yellow, blue and green trio of wires on it, but according to Lawrence that's normal as it's a quick fix for some reason or other.
How many volts does this take in? It'll work fine with the UK 10V adaptor, right? Or is there something else I need to try on an Asian model?

[kendrick]

Oh hey, there is another gotcha on the Mark I that's easy to miss. That power supply is a negative tip, positive sheath (backwards from the Mark II and every other properly shielded power supply known to man.) If you're using a universal adapter or wiring your own, make sure the polarity is correct.

-KKC, having another bad hair day.

[Vertigo]

Aha! That may be it then. I'll break out the universal adaptor and see later then, although I think mine only does 9 or 12v, not 10. I'll give 9 a go and see what happens anyway, although I am already using a UK MD1 PSU on it and getting nothing.