Unfamiliar pcb & switching

[nulle]

Unfamiliar pcb & switching

I just bought new Asian PAL Mega Drive and was going to add PAL/NTSC switch to it. But when I opened the console I was surprised, PCB isn´t like the one in tutorials.

here´s some pics I took.

click here for fullres

click here for fullres

As you can see there´s no capacitor on jp1 and the jp´s are lined in correct order 1 - 2 - 3 - 4 from up to down.

Do you guys think that it is safe to add switch to this PCB? and if I want to run the games in NTSC mode only is there need to switch or should I just connect jp3 and jp4?

btw. sorry for my bad english

 

[Arakon]

Unfamiliar pcb & switching

there's at least 6-8 different PCB revisions that I know of. the mod is identical for all, the jumper names too. simply do the mod as written in the tutorial, just change it according to your jumper order.

 

[maidtina]

Unfamiliar pcb & switching

Yep i got the same board, well done on finding one with the third joystick port. JP1 to JP4 are the ones below and to the left of the edge connecter for the mega CD, you want to connect the pins to the left of jp 1 and 2 to the centre pole of the spdt switch and the same for jp 3 and 4. Remember to cut the solder tracks between the jp's and you might want to get your multimeter out to check it, make sure the solder points of jp 1 and 2 are linked on the left hand side, the same for 3 and 4, these go to the switch centre pole.

BTW my directions are according to your photo

 

[maidtina]

Unfamiliar pcb & switching

like this -

http://neromancer.users.btopenworld.com/pcbclosesmall.jpg

 

[nulle]

Unfamiliar pcb & switching

Thanks for the help so far, but there´s new dark clouds in the sky ??? I dont have switches yet so I just soldered few wires between JP4 and JP3s holes.

And this is what happens:

colors work but picture runs on the screen.

here´s closeup of my wire setup, have I done something really stupid etc? and is my scart cable ok?

and yes, my tv supports NTSC and scart cable is connected to right spot.

 

[Mike G]

Unfamiliar pcb & switching

Generally speaking, you need to *manually* select the RGB SCART input on a TV. If you leave the TV on a normal TV channel, then hook up the MD and turn it on without changing the input settings, you'll get the effect that I can see in your photo. On Panasonic TVs there's usually an "AV" button to let you select the input.

If you've already done this, have you got the sync sorted out correctly? If you're using a RGB SCART connection, the sync must be taken from the Composite Video signal - if you try to connect the pin labelled "Sync" on the Mega Drive DIN, it won't work. Here's a diagram I did showing the proper connections.

Mike

 

[nulle]

Unfamiliar pcb & switching

Oh boy, Mike you were right, TV settings were all wrong. I couldn´t solve that myself since I was used to PS2 which have no problem like this.

again thanks to everybody, everything is working fine now

 

[Mike G]

Unfamiliar pcb & switching

Excellent.

The reason you have to do it manually, by the way, is because pin 8 (the A/V switching pin) isn't connected in the SCART cable you have. The Mega Drive doesn't provide the 12 volt output that's necessary for this function to work.

Mike

 

[Arakon]

Unfamiliar pcb & switching

actually 5V will work just fine for that. you can link the 5V line from the MD AV out to pins 16+8 and it'll work.