PM-41 MM3 modchip installation diagram

.Towards the end of the PlayStation 1’s life Sony released a slim model called the PSone, or SCPH-10x. Many of these systems have PM-41 boards inside, which is what this page covers. Some of the boards are PM-41 (2) and require you to use a different diagram. The model is printed on your board if you take apart your console.

For more information about MM3 chips click here, for more information about PS1 modchips click here.

PM-41 MM3 modchip installation diagram

MM3 chip pinout

PM-41 MM3 modchip installation diagram

Above is the installation diagram. If you have a PIC12F629, or other chip that needs 5V, you can power the chip from the regulator marked as the first pin on my PM-41 (2) diagram.

Since the diagram isn’t the clearest I’d like to mention that the second pin connects to the right most pin on the top row of pins on the chip. Pin three connects to the top contact on the resistor, and pin six connects to the right contact on the capacitor.

Installation tips

Here are some tips I have for you when you are soldering your chip into the PM-41.

  • You don’t need to connect pins four and two.
  • Pin 3, and 6 can be tricky. Don’t push on the components with your soldering iron or they might get knocked off the board. You can use tweezers to carefully solder them back on one side at a time, the orientation doesn’t matter.
  • Make sure the wire on pin 3 and 6 don’t come into contact with both sides of the component (this is especially common if you run the wire directly on top of the component).
  • Don’t apply too much solder to pin 2 or you’ll bridge the pins on the chip.
  • Placing the chip on top of the chip underneath pins two and seven seems to be the ideal location for the chip.

Diagram success rate

Here’s a list of people who have successfully modded their console with this diagram. Leave a comment and I’ll add you to the list.

  1. William Quade (me) (I’ve used this diagram many times and haven’t had any problems with it)

Example installations

This section has photos of some successful installations which you can use to get a better understanding of how everything is wired and positioned.

Here are some sample installations I have done in SCPH-101’s:

These first two images show a cleaner way to install the chip with six wires. I probed the board with a multimeter to find alternate points to solder the wires to that are much closer together. I use the capacitor to the right to get the VCC and GND (pins 1 and 8) connected to the chip with really short wires.

PM-41 MM3 install

PM-41 MM3 install

Below is a messier 8 wire install I did using points on the diagram. The ground pin number 8 is different, I connected to an alternate ground point. This installation works, but the wires are much longer than they really need to be.

PM-41 MM3 install

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3 Comments on "PM-41 MM3 modchip installation diagram"

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Jason W

Hey William. Just wanted to stop by and thank you for this guide and all of your hard work putting this website together. I am happy that stumbled upon it. I am going to be attempting a PSOne mod next week. My first time doing this. Hopefully I didnt choose too difficult of a project to start with, but Im determined to get it done. Your guides are a huge help for someone like me who is new to all of this. Great work and thank you for compiling all of this info into one place.


I pushed the resistor off on 3. I had a hard time getting it to stick. Also 2 I couldn’t figure out how to solder to.


When I placed the 12F508 on top of the chip under 2 & 7 games would start but I’d have a significant amount of audio glitches and CD drive issues. I wasn’t using a DIP chip so I am not sure if that would have been better but I ended up putting the chip between 8 and 5 with some insulation.