Help with Multimode 3 on NTSC PSOne

**SOLVED** see end of this post

First off, I'd like to say my experience level is something around a medium. Not a super noob, not a professional modchip installer. And my soldering skills are only adequate. (especially considering I attempted this mod a bunch of times and got sloppy out of frustration)


I'm trying to get MM3 to boot backups on a SCPH-101 PM-41A. I'm fairly confident that all my points are continuous and not shorting. Edit - Have tried 12F675 and 12F629. Oscillator value is still programmed (and assumed valid). From what I've read, the MM3 (usa hex I might add) should be working on a PSOne.


My board version: (ignore the serial connection)



Install Diagram:



Wiring:



12F675:



When I insert a backup, I was only get the Audio CD menu. Now after another time of rewiring/rewriting chip, backup only gets red insert playstation disc. Any thoughts on why this isn't working, please let me know.
Also, Old Crow works flawlessly.

* Solved -

All diagrams that I could find (normal sources, google, etc) did not have pin 4 leading anywhere.

This is the correct diagram for NTSC PM-41 thanks to bad_ad84's resources:

 

If I remember correctly, I had the same problems and had to go with the Mayumi 5 mod instead.

 

Does any Mayumi work with 12F series chips?

 

Does 4 not need connected like on the older models

 

From the diagrams I've seen, there is no 4 connected on SCPH-101 for any chips. Unless you can point me to one, which would be great.

 

Go to bad_ad84's sale thread and he has diagrams for install of mayumi v4. The psone diagram has the location of point 4. Not sure it is what is needed though.

all the other diagrams seem to match except for mm3 not requiring point 2

 

Thank you for the tip. Basically it looks like all the diagrams I've seen for MM3 are what he has for OneChip (which includes wiring for ntsc fix I assume?) Perhaps this is wrong. His diagram for Mayumi v4 I've never seen before, I might give that a go.

 

Should hopefully just need point 4. The ones that may be different from the above diagram are just different locations.

 

Pin 2 is also different from mine. They aren't wired in my install, so I'm assuming that if this is a wrong diagram, nothing bad will happen. Cough.

 

Do not connect pin 2. MM3 does not have that connected. I am not sure what pin 4 is for but all other boards need it for mm3 so I would assume the psone does too. I could be wrong though. Not sure why all the diagrams would be wrong.

Edit:
I'm pretty sure pin 2 for mayumi is the oscillator (which is built in to MM3). All other points appear to match between mayumi and mm3 which is why I'm thinking point 4 needs connected.

 

Thank you, that was it. Pin 4. Every google search for SCPH-101 and MM3 pointed me to diagrams that just didn't have anything for this pin. Try searching yourself.

The source for the 629 version even had pin 4 listed in it's ascii diagram, but says "Don't refer to the following pinout, but to multimode 3 installation schematics." I shouldn't have listened.

 

Cool. Glad you it. I had an issue finding the mayumi diagram for pm-41 (2) board. It seems like the 2 psone motherboards don't have very good install info out there for the NTSC versions.

 

Pin 4 is the reset line - and since a PSone doesn't have a reset button you just tie it to the +ve supply - I.E. it has to go to the same place as pin 1.
For reference, Pin 2 is the external clock line, which is a no-connect on the MM3, since the fuses are set to use the internal RC clock. The Mayumi chip does use it as an external clock, and should be connected to the mechacon clock (I.E. pin 14 on the 52 pin package). Connecting it on the MM3 is unnecessary, but harmless.

 

As always TriMesh is always a great help for those that are doing their system mods. This guy knows his stuff

 

Hi guys, i will have a guide on the scph-101 ntsc u/c pm-41 (1) for the multimode 3 modchip on my site in a couple of days. I have tested it with a PIC12F508 and works like a charm!
http://www.dopkomachine.ca

 

Hi all-

Going to embark on installing an MM3 in my scph-101 ntsc. I am just wondering which of the diagrams I should use. The one posted in the original message, or the one from dopkomachine?

http://www.dopkomachine.ca/psx.html

Any help would be greatly appreciated.

Thanks,
Josh

 

There both the same. Pin 2 is not needed.

 

Perfect, thanks. I also noticed that pin 8 is in a different location. Is that just an alternate point?

 

Yes, pin 1 and pin 8 are just power.