Dreamcast Modchip

 This mod is only for playing imported commercial games without the use of a boot disc.
(As for now, no other functions are available on the modchip, but I really hope that someday,
someone can/will implement a MP3-, VCD- and DivX-player, so there’s absolutely no need at all for any boot discs.)


Warning:
This mod is MODERATELY easy to perform, so I expect you to have at least some soldering skills.
Also, I expect you know how to safely disassemble the DC.
I cannot be held responsible for any damage you encounter while performing this mod.
I must stress to be careful with soldering irons and hot glue guns, as THESE CAN BURN YOU!


These are the things you'll need to perform this mod:

- 1 Dreamcast (PAL/JAP/US)
- 1 modchip
- 1 Philips screw driver
- hot glue gun
- some isolation tape
- soldering iron and some solder
- 4 lenghts of kynar wire (different colors, about 15 cm each to be safe)
- 1 length of kynar wire to bridge chip connections (other color, only +/- 1 cm)

- OPTIONAL: 1 length of kynar wire for PAL R422 fix (+/- 1 cm)

 
You’ll have to solder 4 points on  top of the mainboard, so there’s actually no need to take out every piece of hardware.
But, if you want to perform the PAL R422 fix, you’ll have to take out the motherboard.
It’s best to do the PAL R422 fix FIRST, as it’s on the underside of the motherboard.
The HOW-TO for this is at the end of this tutorial.

Begin with plugging in the soldering iron, as now you can disassemble the console and the soldering iron will have the desired heat when the disassembly is done.

Connecting the wires to the chip: 

If you look closely, you’ll see that the chip itself has 3 straight corners and just 1 rounded corner (top left in the first picture).
Hold the chip upside down (print facing downwards) and have the rounded corner in the middle to your left as in picture 2.

You don’t have to use the same coloring for wires, just make sure you keep the same connections!

I start counting clockwise from the first pin I come across, starting from the top middle.
Solder the 4 wires to the chip like this: attach the green wire to pin 1, the small purple wire to pin 4,
the grey wire to pin 6, the blue wire to pin 9 and the orange wire to pin 11.

Now bridge the purple wire to pin 4 on the next side. Done!

It’ll look like this.

Connecting the wires to the motherboard:

 If you are using a Japanese machine that has watercooling, make sure to route the wires underneath the watercooling duct
BEFORE soldering, because the shielding has to be placed on top.
Connect the orange wire to the 6^th pin from your right (pin 28 on the MPR-chip),
the blue wire to the left side and the grey wire to the right side of CE502.
Now for the last wire, this one goes on the left leg of D521.

As you can see, I’ve taped the wires to route them correctly and they would stay put during soldering.
Afterwards I glued them to the motherboard with hot glue, because the tape would tend to loosen too much.

Put the shielding back on and navigate the chip through the hole for the paper ribbon.
Now tape up the chip, so it doesn’t short out anywhere.


Before                                                                        After

When all of the components have been reassembled, it’s time to make sure the chip stays where it should.
You can do this by using some tape or glue, next to theGD-drive is a good spot.





                



PAL R422 fix:

If you’ve got an NTSC console and you live in a PAL country, you may have some strange problems with PAL games.
The image may disappear at the top/bottom of the screen, or have a weird flicker with a handful of PAL games or Passport Discs
(a good example is Tokyo Highway Challenge 2).

It is very easy to fix, and combined with a 4-wire modchip, you'll end up with the most compatible universal Dreamcast.
You need to look for a pair of points labelled R422, they are near the AV Out port.
Once located, simply link them up by adding some solder, or even better, with a piece of kynar wire
(which I forgot in the picture, so I used some solder).

PERMANENTLY FIXED!

 
normal view                                                                zoomed in

Alternative solution:

Instead of soldering, you can always try to fix the picture through the software itself.
The screen of Tokyo Highway Challenge 2 can be fixed this way: when booted, the game shows the CRAVE logo,
NOW is the time to soft-reset (START+A+B+X+Y)!
Instead of soft-resetting, the game continues and there’s a screen repositioning noticeable.

(This only works for Tokyo Highway Challenge 2 AFAIK, and has to be done each time at start-up.)
 


Disclaimer/copyright:

SEGA and the Dreamcast logo are copyright of SEGA Corporation.
I know there are various chips and diagrams on the internet, I’ve seen two different diagrams on the same model chip,
but this one is guaranteed to work on PAL & NTSC consoles.

I saw the PAL R422 mod when browsing through this site: http://www.mmmonkey.co.uk/

The actual improvements, tutorial, pics and explanation are entirely mine.

This tutorial is free to distribute to the community, ONLY in its original PDF format.
No changes allowed without my permission!
If needed, I can always be contacted through the known channels.


Have fun!


Shinebi
11/2006

Download here

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