Help with 60hz Saturn mod

[breeza]

Hi,

I have a VA9 board UK Saturn that I want to mod. 50/60hz switch & region mod.

The following site looks like it has all the info I need. I understand the region mod fine and I should be able to sort out a three way switch with some logic for a UK/USA/JAP selection but I don't quite understand the 50/60hz mod as its shown.

http://www.trsoft.demon.co.uk/satmod.htm

Its the follwing diag that doesn't make sense to me



Surely it should be more like this:
[code:1:1892e0bf88]
------------------------- +5v
|
/
|--------to 50/60hz on the saturn board
---
| |10k (Used as a pull up resistor) when switch is closed
| |
---
|
--------------------------- 0v
[/code:1:1892e0bf88]
Switch open, 50/60hz point is at 0v = 50hz
Switch closed, 50/60hz point is at 5v = 60hz

Can someone offer me any advice? I have installed a Messiah into my PS2 and made and fitted a homebrew mod for my XBOX so I'm not a complete novice.

Thanks

Breeza

[ZeroRisk]

That didn't make much sense to me either. I just installed a switch on JP1 and hey presto! I have the circle button Saturn by the way, forgotten the board number.

[MD]

Ignore that diagram as it makes it harder to understand....

In the early Saturns a switch over JP1 would switch the machine to 50/60Hz these were mainly the Oval Button Saturns.

In the later Saturns, the more common Circle button ones you need to use the track method.

Get a SPDT switch (has 3 legs) and break the track as in the diagram, solder a wire to the spot that is there (tin the wire first, makes it easier to solder and cut the wire so the exposed bit is fairly small), solder a wire to 0V and another wire to 5V (use a Multimeter to find these but it's not hard to find them). Solder the 'Green' track wire to the centre of the switch and 0V to one free Pin and the 5V to the remaining one and lo and behold a switchable saturn... finding spots to drill a hole to put the switch is your problem. :P

[breeza]

Thanks for your help.

I don't think the JP1 switch would work on my board as it looks like that would short the +5v & 0v lines!

From your advice it sounds like my pull up circuit would work just fine. I will try it on Sunday when I get some more kynar wire.

I thought about drilling 2 holes just above the controller ports??

Cheers

Breeza..

[mmmonkey]

I've done it the same way that MD describes, works with no problems whatsoever. I can't remember my board number but it was a saturn with round buttons. I did try jp1 first out of curiousity but it never worked.

You may want to look here www.mameworld.net/pc2jamma/satmod1.html for some more info. I followed this guide to do my country mod aswell.

Pete

[breeza]

I found that the switch circuit instructions at mameworld didn't work for me using a 74LS04. The pull down resistor method shown caused the hex inverter inputs to sit at about 1.2v which is not logic 0. I changed it all around to use pull up resisters and all is now fine.

My circuit above also worked fine for the 50/60hz mod

Mounted the switched either side of the Sega text on the front of the case.

Job done.