Sega Saturn Region Free BIOS

[Emperor Udan]

Region Free Bios: Done.
Modchip: Done.
220v psu: Done.

For the 50/60 switchless, I found this:
http://www.gamesx.com/importmod/sat_switchless.htm

I read carefully and, miracle, I understood almost everything. ^^
And here is the bonus:

You'll need a 74157 IC which can easily be found for less than a dollar. If you don't want to special-order such a cheap part, go and rip one out of your favourite 3-button Genesis or MegaDrive controller.

So I picked up this chip and start working:


But I fail...:banghead:

Here is what I tried:



First pin 14 was connected directly to +5v from psu, not to JP1, thinking JP1 delivered 5v.
Then I tried like picture above.
When I start my Saturn, picture is scrambling in black. :confused:
I don't understand what is wrong.

[Segata Sanshiro]

Look forward to hearing if you find the problem.

Shall have to copy this for 50/60hz too.. :D

Would save my plan of install a discrete switch in the drive bay.

[Druid II]

I don't have the schematics for that chip, but the 50/60 switch only needs +5v on/off. So you cut the trace that connects jp1 and/or jp2, and hook the signal up to the center line. +5v can come from anywhere in particular.

And I remember someone having issues with the switchless mod because the small clock gen ic (IC20) didn't have one of his pins lifted right. I don't know why that is required though, since all you do is sending either ground or +5v to the target signal, same as with a hard switch, and that doesn't need that pin lifted either. Oh well, give it a try, you have to lift and ground pin1 on ic20.

[Emperor Udan]

I find this on IC20:
http://www40.atwiki.jp/arcadegames/pages/65.html
Pin 1 seems to be NTSC/Pal entry changer.

I made a simple 50/60 switch to be sure my saturn was still working properly.
Results:



Everything was working before this Genesis controller chip installed.
Now I must check my system but don't know how to do this. :-(:crying:

Any track to follow?

Edit: I tried lifting and connecting pin 1 from to ground but was not working.

[Druid II]

Need more info. How does your machine look right now, what is soldered where, how does it behave, etc.

[Emperor Udan]

Modchip in correct place.


Pal PSU in correct place, with pin 9v cut from psu and join with 5v:


Modchip in place, with 5v connected to psu:
No pics.

At that point it was working flawlessly.
Then I tried installing frequency switchless.
At first I tried this:



Starting my Sat, screen goes black and flickering.
Then I tried this:



Same issue.
I remove the switchless chip and put a simple switch.
It switch between JP1 and JP2 as it should be.
Same issue.:confused:

[APE]

I don't see how that'd work honestly. You'd only get one of the video modes and not have a switch.

The two left side pads of JP1/2 are where you need a wire each with one wire being the "common" wire on only ONE of the two right side pads. Cutting the connection at JP1 severed what I assume is 50hz mode if you have a PAL Saturn.

What I'd suggest doing is to remove everything and restore JP1 to see if the poor thing still works. If it does I'd try again with a different method if possible.

[DarthCloud]

This mod is poorly documented, The way it's looking to work as soon you release the reset button the jumper will be set back to it's default position. So I don'T see how it could work.

Don't waste time with that mod remove everything like APE suggested and use a normal switch.

or

Set it permanently to 60Hz, and since you have a modchip download the US version of the PAL original you have.

[Emperor Udan]

I just put switch back to normal and it works again.



I had soe weird issue rebooting it.
At first it tell me to set time and date but it had glitch over the screen.
when time and date were set, it boot over again...

I remove the power cord and the battery and everything is working now.
I test it during half an hour and it works flawlessly. :shrug:

Now that it's fixed, I will try one last time the simple switch, I don't know why it should not work.

I'll post in less than 30 min.

[Emperor Udan]

So It test that:



It works in 60hz but not in 50.
Picture is scrambling like when you put a 24hz jamma pcb on a 15hz screen.
And when I hot switch back in 60, saturn freeze.

Any idea?

EDIT:

And I remember someone having issues with the switchless mod because the small clock gen ic (IC20) didn't have one of his pins lifted right. I don't know why that is required though, since all you do is sending either ground or +5v to the target signal, same as with a hard switch, and that doesn't need that pin lifted either. Oh well, give it a try, you have to lift and ground pin1 on ic20.

I should try this.
So I lift pin 1 from IC20 and connect permanently to GND, or I use a double switch > connecting pin to GND only when in 50hz?

[APE]

In this case we should be messing with vsync and not hsync, unless those jumpers aren't what we think they are.

Probably a dumb question, but did you double check the wiring on the switch side as well as double checking that 50hz was completely severed?

[Emperor Udan]

In this case we should be messing with vsync and not hsync, unless those jumpers aren't what we think they are.

Probably, but it goes away from my knowledge.

Probably a dumb question, but did you double check the wiring on the switch side as well as double checking that 50hz was completely severed?

Switch side is clear.
I checked again JP side with my multimeter.
JP2 goes to GND.
JP1 to JP1 and trace that go to middle of the JP is cut.
The middle of the JP is well soldered.

what do you think about DruidII idea for IC20?

[Calpis]

With a 50/60 Hz switch the logic inside the chip switches, but unless you swap the crystal the timing will still be off.

Also yes the '157 circuit doesn't make any sense because it has no state/memory.

[Emperor Udan]

With a 50/60 Hz switch the logic inside the chip switches, but unless you swap the crystal the timing will still be off.

You mean 50/60 switch only works on image size and not the speed of the game?
I'm sorry if I misunderstood but my English like my knowledge in electronics is not rich.:rolleyes:

Edit:
After searching for info, I think I'll try this:
http://www.mmmonkey.co.uk/console/sega/saturn5060.htm

Wish it will not frie anything...

[Calpis]

If you have a NTSC console and you install a 50/60 Hz switch, when you switch to 50 Hz the frame timing will not be correct for 50 Hz because you will still have a NTSC crystal.

[Emperor Udan]

Oh ok.
I guess I leave my Jap system this way if it is frequency unswitchable.
It is already modchiped and region free, more that I expected. :-)

I now will do the same on my pal system, wich is already frequency switched. By luck, it will accept region free and modchip, so I can put the mobo in the beautiful withe Jap system. ;-)

Thanks again to evreyone helping me trough the process, honestly this forum rules. :pray:

[Druid II]

Cutting the connection at JP1 severed what I assume is 50hz mode if you have a PAL Saturn.

With a 50/60 Hz switch the logic inside the chip switches, but unless you swap the crystal the timing will still be off.

No, JP1 is +5v for ntsc mode.

Basically you have pin 79 on the VDP2, and pin 7 on the video encoder linked together. If this machine is pulled low, the machine will internally switch to 50hz mode. If it's pulled high, then it's switched to 60hz mode. It will not change between pal/ntsc however, you need to change a resistor for that near the video encoder. So really, you get PAL60 or NTSC50 or whatever, which is only an issue if your TV doesn't know what to do with crazy signals like that (but, most sets that support both pal/ntsc will handle this no problem). Or you can use RGB and not give a fuck really.

Switching the modes will tell the saturn to run in both the respective screen size and speed, so there's really nothing to worry about here. The screen won't go black and white because of wrong oscillator setups like on the Megadrive, if that's what you guys are implying.

This line has two "jumper" spots lined to it, JP1 and JP2. JP1 connects the line to +5v (for 60hz), JP2 to Ground (for 50hz).
The trick is that the video switcher line is pulled low internally. So you just need to cut a trace on jp1/2 (whichever is connected), and install a on/off switch between vdp2 pin 79 and a +5v source. If you get nervous from lifting those teeny tiny pins on the chip, you can solder to the common point of jp1/2 instead, the only downside is that it's on the bottom of the board (excuse the pun), which can make cable routing more difficult.

PAL VA SD models actually omit the JP2 switch cause the chip is in 50hz mode by default anyway, as the line is pulled low like I mentioned. So just put the on/off switch on there and you are done.

I'm not sure what pin1 on IC20 actually does. On the VA0 schematics, it says it is connected to the same 50/60hz control line. But it should be just something that "informs" the main cpu that "yeah, I'm working in this mode, adjust all clockspeeds accordingly!". I've modded va0, 1, 3 and 5 machines from 50/60 without ever touching IC20.

So if the switchless mod is just a question of adding a state switcher that alternates between sending +5v or gnd depending on how many times you press reset, then there's no reason why you should touch IC20. Because you are doing the same thing as the hard switch mod, just instead of the hard switch, you are just using a state controller to switch between gnd/+5v. This is why I don't understand why all those guides explicitly mention to pull up and ground IC20 pin1.

Also, I've yet to try adding a 50/60 mod to my VA9 machine. The guides for that one say all sorts of crazy things, from cutting random traces to lifting the vdp2 pins directly. Once I'll test if all that is horse shit or if you actually need to cut those traces.


I really need to sit down and make a proper documentation webpage for all of this crap at one point.

[Emperor Udan]

I'm using rgb cable, so it don't matter of pal or ntsc signal output.

I tried lifting pin 79 and connect it in a middle of a switch.
Other legs of the switch were connected to gnd and 5v from psu.
But it don't work.
Then I cut JP1 from 5v and try again like above, but it don't work.
I don't care for now the switchless mod, I only want to had 50hz possibility for the few pal game working properly only in 50.

Actualy my saturn only has region free bios and modchip, all the rest is like the original way.

After trying pin 79 and regular JP 1-2 switch, I don't know what to do.

[Druid II]

If the hard switch works right and you already have it installed, then the thing you should do is sit back and play some saturn games.

[Calpis]

<omg text> ...Switching the modes will tell the saturn to run in both the respective screen size and speed, so there's really nothing to worry about here. The screen won't go black and white because of wrong oscillator setups like on the Megadrive, if that's what you guys are implying.

??? VDP, pixel, colorburst and CPU clocks are all derived from the master crystal are they not? The jumpers change the status flags, PLL, divider logic and frame timing logic, but they cannot synthesize the correct frequency from the wrong crystal.