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Name may change but just needed something to start a thread.
I originally had a PS2/Wii project in mind but then opened my drawer to find a disassembled PSONE. I've always loved the PS1, was my first console and has so many great titles. Sure, emulation or just a PSP exists, but there is no fun it that. Original hardware for the win!
I know nothing about the hardware of the PS1/PSONE, so what better way to gut it and scan it.
(Not my photos of the motherboard with the components, pulled off google)
(These scans are my photos)
View attachment PSONE PM-41-2 SMALL RAM TOP.jpg
View attachment PSONE PM-41-2 SMALL RAM BOTTOM.jpg
I wish I could just do something simple, but my mind doesn't think that way... I need a challenge. If yall have seen some of my other threads, we meet again. Time to redesign the motherboard. I specifically chose the PSONE 41 (2) because of the small package CPU RAM. It is kind of a gamble because some of them come with the larger RAM.
The Wii's motherboard design is sensitive, that's still a WIP, as is the N64, but the PSONE is all low speed stuff and can have wires running all over the place and still just "works". Shouldn't be much problem in theory.
Kicad schematic are very early on:
The image above is a 3" x 3" board, but as you can see I may be able to get it smaller. I also might just use the extra space to throw a PSIO on board as well, we'll see. I don't want to get too ambitious lol.
I plan on replacing the stock video DAC with the ADV7123 video DAC as the stock DAC requires 5V and won't boot off lower voltage as I plan on undervolting, more on that later. ADV7123 requires at least 3V according to datasheet, but hopefully can go a little lower as I was thinking of using the Shinobi Scaler since it cleans up the image really nicely with 15KHz VGA in from the PSONE to 31KHz (480P) out from the Shinobi Scaler. Some of you may have seen on the Discord but I messed with undervolting the Shinobi scaler and get it to go from 2.16W running at 50C temp to a little over 1W by undervolting the 3.3v line to 2.5v and 1.8v to 1.5v, also creating less heat and running only at 40C with the stock GBS 8200 heatsink in open air. If the ADV7123 cannot be undervolted to the same level as the Shinobi scaler and the rest of the motherboard, I may be forced to use a boost reg which I hope will not be the case. I guess I'll see how low the PSIO can go too...
First started off with removing a ton of components to see what is essential and not. I think there is more I can remove but still quite a bit taken off.
As you can see, the audio amp booster IC was removed and analog audio can just be harvested from the SPU directly. In addition, the Sub CPU was removed after discovering the PSIO replaces it! You just have to make sure the settings are correct to get audio. Set "Execution Mode" to "LoadExec" and "EXTDSP" to "KIV4". Unfortunately, PSIO has some issues with CD audio with and without the Sub CPU that is just a compatibility issue with the PSIO itself.
BIOS chip trimming anybody? Looks like a spider
Stock untrimmed BIOS IC 21mm x 12.5mm, but looks like it can be trimmed to 11.5mm x 11.5mm. I plan on leaving it stock. Don't worry, this bios was completely rusted and dead anyway.
Last I did some undervolting tests in the PSONE 41 (2) as it was the very last revision of the PlayStation console and had some die shrinks. I only measured consumption from the 3.5V line and 2.5V line as I plan on removing 5V entirely if I can get away with it.
Total consumption of the stock board of just the 3.5V and 2.5V lines on the PSONE BIOS menu was about 0.8W.
I was able to take the 2.5V down to 1.8V (didn't test any lower than that) and the 3.5V to 2.5V (didn't test any lower than that) and power consumption went to just 0.4W of those two power lines on the PSONE BIOS menu!
I noticed the official Sony controller was not recognized any longer with the 3.5V line at 2.5V, but read the PS2 controllers work with PS1 just fine, so I tested a board I bought from @ohkin86 on AliExpress and it works on 2.5V!
Here's what the chip is that works on 2.5V:
I read somewhere that this is an MCU so I'm not surprised it works off lower voltages. Too bad they are not sold anymore with no way of sourcing them either.
Much more work to do but this is a start.
I originally had a PS2/Wii project in mind but then opened my drawer to find a disassembled PSONE. I've always loved the PS1, was my first console and has so many great titles. Sure, emulation or just a PSP exists, but there is no fun it that. Original hardware for the win!
I know nothing about the hardware of the PS1/PSONE, so what better way to gut it and scan it.
(Not my photos of the motherboard with the components, pulled off google)
(These scans are my photos)
View attachment PSONE PM-41-2 SMALL RAM TOP.jpg
View attachment PSONE PM-41-2 SMALL RAM BOTTOM.jpg
I wish I could just do something simple, but my mind doesn't think that way... I need a challenge. If yall have seen some of my other threads, we meet again. Time to redesign the motherboard. I specifically chose the PSONE 41 (2) because of the small package CPU RAM. It is kind of a gamble because some of them come with the larger RAM.
The Wii's motherboard design is sensitive, that's still a WIP, as is the N64, but the PSONE is all low speed stuff and can have wires running all over the place and still just "works". Shouldn't be much problem in theory.
Kicad schematic are very early on:
The image above is a 3" x 3" board, but as you can see I may be able to get it smaller. I also might just use the extra space to throw a PSIO on board as well, we'll see. I don't want to get too ambitious lol.
I plan on replacing the stock video DAC with the ADV7123 video DAC as the stock DAC requires 5V and won't boot off lower voltage as I plan on undervolting, more on that later. ADV7123 requires at least 3V according to datasheet, but hopefully can go a little lower as I was thinking of using the Shinobi Scaler since it cleans up the image really nicely with 15KHz VGA in from the PSONE to 31KHz (480P) out from the Shinobi Scaler. Some of you may have seen on the Discord but I messed with undervolting the Shinobi scaler and get it to go from 2.16W running at 50C temp to a little over 1W by undervolting the 3.3v line to 2.5v and 1.8v to 1.5v, also creating less heat and running only at 40C with the stock GBS 8200 heatsink in open air. If the ADV7123 cannot be undervolted to the same level as the Shinobi scaler and the rest of the motherboard, I may be forced to use a boost reg which I hope will not be the case. I guess I'll see how low the PSIO can go too...
First started off with removing a ton of components to see what is essential and not. I think there is more I can remove but still quite a bit taken off.
As you can see, the audio amp booster IC was removed and analog audio can just be harvested from the SPU directly. In addition, the Sub CPU was removed after discovering the PSIO replaces it! You just have to make sure the settings are correct to get audio. Set "Execution Mode" to "LoadExec" and "EXTDSP" to "KIV4". Unfortunately, PSIO has some issues with CD audio with and without the Sub CPU that is just a compatibility issue with the PSIO itself.
BIOS chip trimming anybody? Looks like a spider
Stock untrimmed BIOS IC 21mm x 12.5mm, but looks like it can be trimmed to 11.5mm x 11.5mm. I plan on leaving it stock. Don't worry, this bios was completely rusted and dead anyway.
Last I did some undervolting tests in the PSONE 41 (2) as it was the very last revision of the PlayStation console and had some die shrinks. I only measured consumption from the 3.5V line and 2.5V line as I plan on removing 5V entirely if I can get away with it.
Total consumption of the stock board of just the 3.5V and 2.5V lines on the PSONE BIOS menu was about 0.8W.
I was able to take the 2.5V down to 1.8V (didn't test any lower than that) and the 3.5V to 2.5V (didn't test any lower than that) and power consumption went to just 0.4W of those two power lines on the PSONE BIOS menu!
I noticed the official Sony controller was not recognized any longer with the 3.5V line at 2.5V, but read the PS2 controllers work with PS1 just fine, so I tested a board I bought from @ohkin86 on AliExpress and it works on 2.5V!
Here's what the chip is that works on 2.5V:
I read somewhere that this is an MCU so I'm not surprised it works off lower voltages. Too bad they are not sold anymore with no way of sourcing them either.
Much more work to do but this is a start.
Last edited:
