Video mod, the easy way?

[antime]

I was probing around on a Saturn board (as you do on Thursday evenings) when I noticed a place for a switch near the rear, next to the battery slot. After a bit of tracing, it turns out the middle pole is connected to pin 79 of VDP2 which is the pin you use to switch between 50/60 Hz!

Can someone else confirm this? If I'm correct it's a bit odd that it's gone unnoticed for so long and that we've been cutting traces, lifting pins or other acts of violence instead.

(edit: Not surprisingly someone else discovered this earlier.)

 

[Runik]

I already saw this kind of mod in some other french Sega board ... it's worth the try, and I think I'll do it someday

 

[RockinB]

I see this for the first time. Cool stuff!

 

[antime]

The whole pin 79 setup is kind of weird. Underneath VDP2 there is a pull-down resistor (R29) and a jumper to 5V (JP1), so far so usual - leaving JP1 open means the system runs at 50Hz, bridging it makes it run at 60Hz. However, under SW4 there is a jumper between the pin79 line and SW4's GND (JP19) but even more strange SW4 and JP19 are connected to GND via JP16, but JP16 is bridged by a PCB trace between the solder pads. I'm guessing JP19 and JP16 are leftovers from an earlier board layout the designers didn't feel warranted the trouble of redoing, because as-is it only presents an opportunity to short-circuit the board.

 

[hkzlab]

Today i recovered (another) PAL saturn and decided to give this mod a shot.

To be fair instead of putting there a switch, i just connected the two solder pads (50hz gives me the headaches :-( ) to simply go 60hz all the time.


Worked like a charm, i didn't even had to remove the shielding, done it directly from the back of the saturn with the chassis on.

Total time for the mod: 4 minutes, including my soldering iron heating up time

 

[mrkotfw]

Why the need for a switch? Do some games not work correctly under 60.0Hz?

 

[ExCyber]

Why the need for a switch? Do some games not work correctly under 60.0Hz?

Some games are optimized for PAL/50Hz resolution/framerate and will have some quirks at 60Hz. Examples IIRC include the PAL releases of Bubble Bobble/Rainbow Islands and Guardian Heroes.