Sega Saturn JAP + 50Hz

Hi everyone.
I'm playing around with a stock JAP NTSC Mk1 Saturn and planning on installing the region free bios along with some other mods. One of the things I'm planning on trying is the 50/60hz switchless mod so it can play those few PAL optimised games that have problems in 60hz.

Initially i'm not getting a picture when selecting 50hz and bringing pin 79 of the IC to 0v.

I know a NTSC console will therefor be attempting to output NTSC-50, which is not really a supported frequency even on a CRT TV that supports PAL and NTSC because of the colour burst frequency from the NTSC crystal...

But I've also read that this shouldn't be a problem if I use a RGB cable, which I'm doing.. but as I said no picture on 50hz

another point to consider would be the wiring on the SCART cable which is different between the cync and 9v line on and NTSC. This will be the next thing to check..

What I'm wanting to ask is has anyone managed to get a 50hz picture from a NTSC Saturn?
I'm happy to leave it in 60hz if that's the only option.
Thanks

 

Are you lifting pin 79 or connecting to one of the other points around the board?

 

To the JP 1 and 2 on the underside. I separated the common points between the 2 jumpers so effectively pin 79 is isolated.

 

On certain revisions, it connects to another chip too. If memory serves, its the clock generator chip.

This is probably your issue. Lifting pin 79 works on all revisions.

Edit:
Link, http://segasaturngroup.proboards.com/thread/6888

 

Thanks mate I'll try that next. Should I return the jumper to JP1 if it needs to send the signal to clock gen?

 

Yep

 

Guess what? You were right.
Lifting pin 79 Did the job. Sometimes the simplest solution gets it sorted best.
I can now switch between 50 and 60hz and tested the 50hz optimized games, all working perfectly.
Thanks