Quoted from Gott_Lieb:
I disagree with what Chris stated in the PW, where it is not worth it. I've done it several times, and prefer to always use less components when there has been battery damage. Plus, you no longer need +12v in the reset section and you can remove that toaster oven of a resistor, R11, which commonly fails. Here's a pic of how I do it. This is on an MPU-200.
I totally agree with Jim. The Dallas reset generator is the only way I do it now and would never go back to the factory circuit.
My notes say R11 is needed, so Jim obviously does this a different way, but here's what's needed in my method:
R11 82ohm 1W resistor
CR7 1N4148 diode
CR5 1N4148 diode
R12 270 ohm 1/4W resistor
C13 .01 disc cap
^^^ These are components in the original circuit that you will need to replace if damaged by corrosion or keep if converting an undamaged board (where the reset circuit has failed, but there is no corrosion.)
Dallas reset generator (in Q5 location, more info below)
1K 1/4W resistor
If you're converting an undamaged board, you only need to remove the following components:
To install the Dallas reset generator:
Run a jumper between the bottom leg of R138 and the top leg of R139 (this can be seen in Jim's pic)
Run the 1K 1/4W resistor from right hole of R140 to the top hole of Q5
That's it -- really simple -- remove 5 components, install a jumper and 2 new components and you're done.
PinWiki says to use a Dallas 1811 reset generator, but you can use others as well. I'm using a Dallas 1233 in my conversions because I got a great deal on 50 of them on ebay.
The difference on these chips is the voltage required to generate a reset, the length of time allowed for the power to stabilize, and the pinout of the chip. The 1811 gives the power supply a little more time to stabilize than the stock Q1, Q5 circuit and the 1233 gives even more time than the 1811, I believe. We're talking a difference of a couple hundred nano seconds here, so you'll never notice the difference when you boot the game.
Here are the pinouts of Q5, so that you can orient whichever chip you decide to use correctly:
Top hole = Reset
Left hole = GND
Right hole = Vcc