[PS2 TWO] Matrix Fix (despues de los diodos...el pic)

The Matrix Team - V12 Dead Syndrome Fix V2.0
- UPDATED 11/22/04 -
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Just a quick follow-up to our previous reports. A more in depth explanation will follow later on but at this
point we believe it's more important to offer a quick fix for all those poor pstwos out there

Further analysis on several V12 has shown that in certain situations the mechanics controller can fail while
communicating with the dvd controller.
You can notice when this happens since the reset button, which is connected to the mechanics controller,
will stop responding and the only way to turn off the machine is to unplug the power jack.

When the mechanics controller crashes, the dvd controller keeps sending a pulse train to the tracking and
focus drivers which results in a steady voltage increase on both the tracking and the focus coils.
With the proposed diode fix, this increase is initially limited but if the user leaves the crashed pstwo on for
several seconds the output drivers will eventually reach saturation and, if the RS2004FS thermal protection
doesn't kick in, the coils can burn from the increased current flowing.

As promised on our latest news, our proposed solution to this problem consists in a simple 12c508 plus
an additional resistor.

There are certainly other solutions to this problems (some of which are currently being tested) which
can offer a more general protection to the coils by constantly monitoring the voltage applied to them.
However we felt that it was much more important to offer a cheap, easy and fast fix instead of a more
general one which would be outside the reach of the general hobbyist.
In a few words : programming a 12c508 pic is something most people with interest in electronics can
easily do. The blank component is very cheap (around 1 USD) and a programmer can be built or bought
for a few bucks if needed.

Further more, this simple fix has been proven to work an all occasions during our tests, so it should
already offer a very high protection.



We are releasing the pic hex file free (as in speech and as in beer ) for all to use and experiment on.
We are also releasing the gerber files for two small PCBs : one can be used with only the pic and the
resistor, while the other has also space for 8 1n4148 smd diodes.
Do with those as you wish : make a few of them for you own use, or build some more and offer them for
sale (hopefully for a low price, since all the research and development cost has been already done .

The simple program to be burned inside the 12c508 will constantly monitor the communication between
the mechanics controller and the dvd controller. As soon as it detects a crash in the communication it will
turn off the pstwo to avoid any possibile damage to the coils.

You can download the .zip file with the program and the PCB gerber files from HERE.
http://www.infinitymod.com/matrix/files/downloads/MatrixFix508v2.zip

Important notes:
The resistor value (1500 Ohm) has been chosen as the best value according to our tests.
If the value is less than 1000ohm the pstwo will stay in a permanent reset state and not even the red led
will turn on.
On the other end if the value is higher than 3300 ohms the pic will not be able to turn off the pstwo when
needed. This has been tested on several machines with consistent behaviour.
However there might be other board revisions which might behave in a different way (maybe because of a
different reset controller IC used).

So if you experience problems with the 1500 Ohm resistor, you can probably safely increase it to 2000/2200
ohms. Please, only experiment with different values if you understand what has been said (or if you don't
care about running your pstwo without being sure that the coils protection is working).

The usual installation care should be used when installing this fix.
Preferred position for placing the pic or the PCB is in the lower left corner of the ps2 motherboard.
Make sure that both a J and K wires run parallel to the board and make them as short as possible.


Last words: this fix can be used with or without the diode fix.
The diode fix can certainly increase the life span of your lens, and should provide you with more time to
realize that your ps2 crashed and turn off the main power, should the pic chip fail to work. This has not
happened once so far in our test, but as usual the real results will come from the thousands of pstwos out
there.