MM3 modchip installation guide
MultiMode 3, or MM3 modchips are very popular, and should work with every version of the PlayStation 1. They can be made using PIC12C508A, PIC12F629, and other PIC chips. This guide covers everything you need to know about choosing, programming, and installing an MM3 modchip into your PlayStation.
Guide structure
This guide is structured into several pages. It’s organized like this primarily so that comments can be more organized and useful for readers.
This page covers the MM3 modchip. It includes general information about the chip, and then links off to installation guides for each console model.
If you want more information about PlayStation 1 modchips in general check out this guide.
MM3 modchip installation diagrams
Below is a list of all PlayStation 1 motherboard versions, along with the console model numbers associated with them. You can get a good idea of what board you have by looking at the model number underneath your system (something like SCPH-7501).
To actually know what board you have you’ll most likely have to open up your console and look for the board version printed somewhere on the board (something like PU-22 or PM-41).
Once you know what board you have you can click on the board model and you’ll be sent to a page with the installation diagram.
- PU-7
- All SCPH-1000’s
- Some early SCPH-1001, and SCPH-1002’s
- Some early SCPH-3000’s
- Some early SCPH 3500’s
- PU-8
- Most SCPH-1001, and SCPH-1002’s
- Most SCPH-3000’s
- Most SCPH-3500’s
- All SCPH-5000’s
- PU-16
- All SCPH-5903’s
- PU-18
- All SCPH-5001’s
- All SCPH-5500, SCPH-5501, SCPH-5502, and SCPH-5503’s
- All SCPH-5552’s
- Some early SCPH-7000, SCPH-7001, SCPH-7002, and SCPH-7003’s
- Some early SCPH-7501’s
- PU-20
- Most SCPH-7000, SCPH-7001, SCPH-7002, and SCPH-7003’s
- PU-22
- All SCPH-7500’s
- Most SCPH-7501’s
- All SCPH-7502, and SCPH-7503’s
- Some early SCPH-9000, SCPH-9001, SCPH-9002, and SCPH-9003’s
- PU-23
- Most SCPH-9000, SCPH-9001, SCPH-9002, and SCPH-9003’s
- PM-41
- Earlier SCPH-100, SCPH-101, SCPH-102, and SCPH-103’s
- PM-41 (2)
- Later SCPH-100, SCPH-101, SCPH-102, and SCPH-103’s
MM3 modchip drawbacks
The biggest problem with MM3 chips is how they base their timing on the internal oscillator within the PIC chips. Using the internal oscillator can sometimes cause the chip to become out of sync with the console when booting, meaning you’ll have to restart the console to boot.
Certain PIC programmers can also mess up the internal oscillator value when programming, which could be a problem if you are programming your own chips. Additionally it has been reported that certain batches of PIC chips have had problems with the oscillator value in the past.
MM3 modchip advantages
The MM3’s greatest strength is its compatibility and popularity. From my experience it is the single most popular PS1 modchip being used today. Because of this you’re more likely to find people who can help you if you are having problems installing your chip.
Additionally the MM3 is compatible with most PS1 consoles and can play anti modchip games if you install all seven wires. The only system that you definitely shouldn’t install an MM3 in is the SCPH-102 (install a ONEchip instead).
MM3 modchip source code
If you’d like to program your own MM3 modchips you’ll need the source code. Right now I only have the code for the PIC12C508A and the PIC12F629. If you have the code for other PIC chips let me know and I’ll add them to this post.
The MM3 chip has three different versions, one for each region. If you have an American system use the USA version, if you have a European system use the EUR version, and if you have a Japanese system use the JAP version.
- PIC12C508A
- PIC12F629
I’ll have a tutorial on how to program these PIC chips in the future.
Hello 🙂 I followed your guide and successfully modified my first console (scph9002)
Thank you so much for your advice
Hi Quade, nice guide!
I have a question, can I write the 12C508A program code into a 12C509A microcontroller, and use the same wire diagram? Thanks for your attention.
Yes, the MM3 hex files linked above work with 12C508, 12C508A, 12C509, and 12C509A. The wiring diagrams will be the same.
Excellent then, thank you very much for the quick reply! I’ll work on it next weekend and give you a feedback.
If I’m interested in trying to program my own mm3 mod chip, do you have a recommended PIC programmer? Did you buy one or make one from scratch? What software do you use for the .hex files, etc? How do I verify that it worked correctly, before soldering it to a PS1.
Thanks in advance. Love the site.
What type of solder and flux do you use?
This is the solder I use (I also use some thinner stuff for some systems, but not the PS1): https://amzn.to/33QBNCY
I use Amtech liquid paste flux.
Hi William!
Can you additionally suggest a good and reliable fine point soldering gun? Just got my MM3 in the mail from you. Excited to install and rebuild my old JP library I had in high school 🙂
It really depends on how much you are wanting to spend.
At the lowest end there are a lot of cheap adjustable temperature soldering iron kits. They are around $20 and will work if you just want something cheap.
A step up from that would be cheap Chinese stations that support Hakko T12 or T15 tips. They are around $50 and up and are a good upgrade.
I use genuine Hakko stations that use the same T12/T15 tips, but they are $200+.
I work as an electronics technician at a college and we use the Weller WES51 series soldering irons with TETS tips. They have worked really well for us, and I highly recommend them.
hi william,
I recently got 2 PIC12C508A chips and I installed one on a psx scph-5502 following your pattern on PU-18 motherboards and it works perfectly with all types of both backup and original CDs.
The only thing is (but I think it’s a psx model problem) that both USA and JAP NTSC games make me see them in black and white maybe you know why?
one last question: the scheme you published ie the 7-wire mod by chance is the so-called stealth modification?
Thank you. Juri.
When using composite video: PAL games on an NTSC system or NTSC games on a PAL system will be in black and white. You’ll need to use RGB SCART video to get color video. This is just how the system was designed.
The MM3 chips are stealth chips (assuming you connect the 7 wires).
Thank you for the response!
i read somewhere that the 55xx series psx have the oscillator which does not reproduce the 60HZ signal.
i connected the rgb cable and the result is identical. i also tried it on my 2015 lcd tv and same thing.
do you think it is for the oscillator?
Every regular retail PS1 console has only a single oscillator (for either NTSC or PAL regions, so the opposite region will always be displayed wrong).
Using RGB video should give you video in color assuming your TV accepts it properly.
There are dual frequency oscillator mods you can do to correct this problem.
Thank you so much William.
Bye Bye…
Does the mm3 come pre programmed I am just wanting to be able to play my ntsc PlayStation so I can play Japanese games on ntsc
The ones I sell do come pre-programmed.
Which one will I need I have a nstc scph-1001 PlayStation so I can go ahead n order the chip
The PsNee chips tend to work better for the 1001.
So I need to order the psnee chip n is there a diagram on ur website for 1001 playstations
Yes: https://quade.co/ps1-modchip-guide/psnee/pu-8/
The Pic12C508A is recognized by my TL866. Any special way to load and write the hex file? Thanks.
You should be able to just import the hex file and click program.
Cool, just like my SNES projects! Thanks.
How to program 12С508 with programmer K150? I did not succeed, it just does not work
I’ve tried to use a K150 programmer in the past and had no luck either. You’ll need to get a better programmer (something like a TL866), the K150 is junk (or at least the Chinese clone I bought was).
hello good site a question also serves the 12C508 / P?
I’m not sure what you are asking. The MM3 code can run on a 12C508A, 12F508, and many other PIC chips.
What does each pin do exactly for this modchip? Interested in technical details. I got it installed first try so loving it!
The source code of the PsNee modchip may be of interest to you. It’s an open source PS1 modchip where you can see what’s happening inside of the chip: https://github.com/kalymos/PsNee/blob/master/PsNee.ino A lot of how these older chips actually work isn’t fully understood since they were never open source or anything. These are the pin functions of the MM3: 1. VCC 2. An optional activity LED output. 3. Used to support stealth mode for anti modchip games. 4. Reset button input. 5. GATE/WFCK 6. Data output to send the correct copy protection serial message so the console accepts the disc. 7.… Read more »
Hello, I installed the MM3 chip in my PU23 board and when I boot up the PS1 it takes me to the audio CD/memory card screen. I didn’t connect pin 2 to anything and connected pin 4 to pin 1. Any ideas what could be wrong?
Make sure your wires are short and there aren’t any accidental solder bridges or anything.
i have PIC 12F675 can i download MM3 PIC12F629 Hix file and work for 12F675
or i must buy PIC 12F629
what a programmer i can use
thanks for your effort
The 12F675 should work. A PICkit should be able to flash them. There are tons of other programmers out there.
Hello, I want to buy the PIC12C508A chip and program it myself, what should I do with the code file that you published? And what device should I use to connect the chip to my computer?
Just open it with your programmer and click program (at least for most programmers). You’ll need to buy a programmer that is compatible with the chip, there are a lot of options. I like the TL866 programmers.
has anyone tried to use cheat devices or cheat discs like gameshark with the mm3 chip, i have tested my 3 cheat carts and like 4 cheat discs with all my modded ps1 consoles running mm3 chips, schp-1001, scph-5501, scph-7501, scph-101, all of them will not work with cheat carts or discs, i think it has to do with the way the mm3 chip uses stealth, on power on the chip will send the wobble code for a few seconds and then stop, well when loading up a gameshark and taking time to pick your cheats the time runs out,… Read more »
This chip will allow a japanese ps1 to boot/play american games normally?
For some models yes, for most no: search for “Japanese PS1 additional region lock” on this page: https://quade.co/ps1-modchip-guide/
ohhhh nice thanks, so basically this chip works with any japanese model before model version SCPH-3000 right?
Yes.
thank you William, I’ll have that in mind if I can’t get an american version.
do you know of any other chip that will do a japanese ps1 region free to play american games on it? I’ve been told that when you chip a japanese ps1 it will read anything (original and copy games and also original games from any region)
As mentioned on that page I linked above there are no chips that currently will bypass the additional Japanese region locking.
The confusion comes from the fact that the early Japanese systems didn’t have the additional region locking.
With this chip, ps1 can read cd-rw? If not, is it theoretically possible someday?
I doubt it would work. It isn’t an issue with the modchip, it’s an issue with the lasers just not being able to read the discs (they struggle enough on regular CD-Rs most of the time)
Hi wiliam,
I have scph-5502 pal, can u help me ,how to chip it?
If you read this page there are instructions.
If i chiped my spch-5502 pal pu18 as i see in diagram, can i burn imeges on cdr an play all region games in color?
Yes, once a chip is installed you can play games from any region. NTSC games will be in black and white if you are using composite video though.
Thanks William 👌
One more question man ,🙏
Are ther some chip or modifications in motherbord , to fix this problem, if colour problem appear ?
🤙
You can install a dual frequency oscillator.
Can I see picture how its looks when it’s done? To do that same my self,
Thanks man ☮
I don’t have any pictures. There are some guides on Google though.
Like this?
Yes.
PIC12C508A-04/SM SOIJ8 1.79€
PIC12C508A-04I/SM SOIJ8 1.91€
PIC12C508A-04/SN SOIC8N 2.76€
PIC12C508A-04/P PDIP8 2.11€
PIC12C508A-04I/P PDIP8 2.51€
PIC12C508A/JW CDIP08 16.03€
Witch to choose, to programme mm3?
Any of those will work.
What AWG wire do you use for the MM3 mod chips?
30 AWG works well.
My scph 7502 pal not chiped is blinkink color imedge, what to do, to fix it?
Was it working before (on the same TV and with the same cables)?
Its worked well with original cabels , until now, image is blinkink, what can it be?
Could be a bad capacitor near the video ports, or the video port on the console being loose in some way (internally, or at the solder joints).
I tryed on older tv yellow and white plugs ,no wer to plug red one ,an it works well witaut blinking, but in black n white .
It could also be a TV issue which is why I asked about if it worked before. Not all newer TVs work well with the PS1.
Ok thank man
Look man, i tried on same tv 2 wires conected wit other scph 5502 consol and it was colorfull withaut blinking, it must be a problem scph 7502 console , not in cables
Hello! I purchased a chip and installed it on my PM 41 psone and it worked perfectly for about an hour. Now it doesn’t turn on and I checked that fuse PS606 from the service manual is blown. I bridged the fuse and some smoke came out 🙁 but the system still turns on so it might be possible to save it. What could be making the fuse blow up? I checked the soldering points with the guide provided in this page and everything seems correctly placed. Thanks!
Probably a short somewhere.
Would the position of the soldering points affect this fuse blowing up? I’m unsure if bridging the fuse without the modchip would still destroy the motherboard, or if I should switch the positions in which I soldered the chip
Hello Wiliiam,
After i manage to modchip my SCPH-5502 Ps1 model with PIC12C508A every burned games runs in a grey image.
It starts fine but when the game is loading image is became grey.
NTSC games on a PAL system will be in black and white when using composite video (and PAL games on an NTSC system will be in black and white when using composite video). Try using RGB video or installing a dual frequency oscillator.
Gday william
My chip wants to work but stops a the playstation screen?
I tripple checked and yes its my first time doin this lol.
Any help wood be good.
Cheers
Scott
If it stops at the black background PlayStation logo screen there is a good chance your laser is too weak to read your backup.
The lasers brand new
Hello, I have a modded ps1 and i wanted to play Pal games on it. But my image keeps moving. Could it be because im using an americant tv? I know they have a different frequence of image in europe so I was wondering if this could be the cause of my problem.
PAL games on an NTSC system will be in black and white with composite video, and have slightly incorrect timing regardless of video connector. A dual frequency oscillator can fix this, but it can’t guarantee that your TV will like it.
Hi, I modded my ps1 SCPH-1002 witha 12c607/p chip. When I insert a copy of a game on a cd-r it will only play it as a music cd… Do you know why this is? Did I mod it wrong or is it a burning problem? Thanks in advance!
Could be either an issue with the installation or an issue with the backup/laser, hard to know for sure from what you said.
i think the laser is faulty. had the same problem on a sega saturn, replaced the laser and it loaded backups fine.
Can I write new code on the PIC12C508A that you sell here? Or you can only write once to it? Thanks
12C508A chips can only be written to once. Generally I send 12F508 for MM3 modchips because they are compatible and cheaper, they can be written to multiple times. If you want a blank PIC chip you can just buy one from Digikey for way less money.
if I use the AV multi out port on PS1 modded PAL, will it also show output in black and white when NTSC disk is played?
Yes, you’ll need to use either RGB video or install a dual frequency oscillator.