Megadrive pad behaving oddly?

[hellbelly]

Can anyone offer any help here - I had a PAL Megadrive with an official 6 button pad and it all worked fine.

I fancied a Japanese Megadrive for the better case design (big gold 16 BIT!) so picked one up cheap off of ebay.  This turned out to be an Asian one.  Anyway, I switched it on and just made sure it would load up a game.  I then went and modded it for EUR/USA/JPN mode.

Finished that off and sat down to play it and now I'm gutted.  With the known good controller plugged into port 1 the Start button doesn't work, plus the Left and Right directions behave oddly (very slow, push left and it gradually goes left then a bit right, then left etc!)

Works fine in the other console, and fine in port 2.  I can't see anything glarying obvious with the socket, or the solder pads on the bottom of the motherboard.

Can anyone offer any advice?

ta
Pete

[albino_vulpix]

This might be a common problem, but I've never heard of the D-pad issue you're describing. Does the C button act as Start by any chance?

[hellbelly]

Nope, A B and C all behave normally.

Pete

[albino_vulpix]

Try reflowing all 9 solder pads in the socket. Problems there aren't always visible.

[hellbelly]

I tried that yesterday and checked the continuity of all of them.  I'm very stumped!

[phreak97]

i'd just suggest checking all your wiring, make sure you got your pin numbering correct when you did the mod, make sure theres nothing bridged.

[hellbelly]

Thanks for the tips

I've removed the mod and hardwired it back to it's defaults and the pad still behaves the same.  I've checked for shorts, measured the resistors, traced the port back to a chip and continuity is fine 

I thought I had found one dodgy contact, but after repairing it it's still the same.  The console is an Asian model, and seems much lower build quality than the Euro ones I'm used to.  To be honest though it did look like someone else had been tinkering around inside it at some point - or did they not ever come with an RF shield installed in Asia?

At least it came with a nicer shell than the Euro model, so I've transferred the insides from another console .

Anymore ideas?

ta
Pete

[phreak97]

pretty sure the asian ones never had rf shielding, i've got an asian pal megadrive 2 which never had rf shielding, and i had another one the same before it.
i dont really know what to suggest now.. how many controllers have you tried? have you tried with multiple games too?

[hellbelly]

That's interesting, cheers.

I need to pick up another controller, I only have one at the moment.  I've tried with a couple of games and it's the same.

Ta
Pete

[phreak97]

just thought i'd clarify, the asian consoles we are speaking of are original sega manufactured consoles, not clones. even being an official piece of hardware, they were still built to a poorer standard.

[Tiido Priimägi]

Asian and western systems are 1:1 inside... just no RF shielding

[phreak97]

schematically yes, but all the components are built cheaper, including the main board, ill take a photo and youll be able to see.