What I have: Never moded PSOne Japanese unit. AM29LV040B programmed with PSOne NTSC-U BIOS. I want to lift up Vss leg of IC102, then connect all legs of AM29LV040B to matching legs of IC102 with wires (WE will go to Vcc). What do you think? Will it work? I suppose, I will get a machine that behaves like a real NTSC-U unit, which means that I should install a SCEA version of Mayumi 4. Will it play PAL games? Another option would be to install a PAL bios, but I'm afraid it will try to set a PAL video mode, which will cause problems with color.
Lifting power pins isnt the way to disable a chip. Lift the /CE line from the original chip and wire to vcc to disable it. You will still have the jap mechcon and would need a jap chip
But will it play eu/american games without a boot cd? Does it make any difference how to disable a chip? I thought that cutting power to a chip would fool the machine into thinking that nothing is connected to bios pads. I suppose the right way to go is to desolder original bios ic completely, but I don't have a heat gun, so the only way for me to get it out is to cut all bios legs. I don't want to do that.
Cutting power will not disable a chip correctly. You can just lift the /ce pin and connect to vcc. Yes, I'd imagine it will play all games as the extra check is in the jap bios
You cannot change the region of a PlayStation, simply by replacing the boot ROM chip. The whole MECHACON will have to be replaced.
You can swap the bios to USA and still use a jap mod chip. This is basically what a xxx3 console is. It also means you can play any region, unlike with the jap bios.
I can confirm that changing the bios you will remove the bios region check protection, so you can use JAP mayumi withou problems
Yep, I did it! Everything works - protected games, unprotected games, PAL games, audio CDs. Black license screen still shows SCEI letters but other than that there is no difference betwen my moded japanese unit and standard western machines. I have to say, this mod is a huge pain in the ass. Soldering is quite easy, but there is barely enough space to fit two ICs and all the wires. I have also tried two methods of disabling original BIOS - by driving CE high as per Bad_Ad84's suggestion and by lifting up ground pin. Both methods work without a hitch, but lifting up ground pin is easier, because it's located near the edge of IC.
Lifting the ground pin isnt the correct way to disable a chip. You can cause problems, If it was an acceptable way to do it, I would have said to do it - for the same reason you describe. please, no one else follow that advice if you do the same mod - its not how to do it. Easier or not.
You can pull vcc and gnd to microcontrollers and they will still run In certain circumstances. Cmos chips have diodes connecting nearly all pins to power and ground. The chip can be powered through its data lines. It may seem ok, but in some situations the chip may suddenly become active and cause havoc. Even without the parasitic diodes, ttl circuits can act in strange ways, possibly cause damage.
Hello everyone. My problem is like TS had, but I dont get it how to make it work properly. Here it is: -Basic console is 5000 (Japan) with PU-8 and 220V PSU (110V was replaced). -I have installed the second oscilator for PAL (53.20mHz) and it work as it must - tested on PAL BIOS -Yeah, when I replace the original Jap bios and put there BIOS from PAL (102, 1002, 7002) the PS1 starts to boot up in PAL video mode. Looks not so smoth like NTSC -Right now there is PAL 1002 BIOS and the 4-wire 12C508a SOP-8 chip with Stealth 2.8a(Jap) firmware. OSCAL is correct. And still - works only Jap licence discs. -It reads only NTSC-J licence and it works in NTSC video mode as it must. Also there is SCEI sigh on disk boot screen. Great, I mean the dual PAL&NTSC mod works and its great. #### So, here is the two questions: -Before I was able to test 101 USA BIOS and it works (booting up in NTSC video mode). Might it damage the console somehow? Seems I better use him to be installed. -What firmware, chip or soldering scheme should I use for 102, 1002, 7002 and 101 bios? The 101 is most important I think. I have 12C508 or 12F629, so there is no problem with chip/firmware.
Well, it does not work still. I don't get it why the SCPH-500x should be mod using Mayumi v3 or v4. I am talking about that thread: http://assemblergames.com/l/threads/tutorial-making-your-own-ps1-modchips.55904/ Fat SCPH-100x = Stealth 2.8a Fat SCPH-500x-900x = MM3 or Mayumi v4 PSOne Slim = MM3 for NTSC, OneChip for PAL console Can someone explain if I install SCPH-101 bios into SCPH-5000 PU-8 board - the chip, firmware and its installation method should be different from classic 4-wire Stealth 2.8a for PU-8?
The jap consoles have an extra region check in the bios. You have to swap the bios to get imports to work. I don't understand your confusion, as this is all detailed in this very thread.
Hello, yes I understand cause I have read all the thread. -I swaped original Japan BIOS and put there scph-101, so, now its Japan PU-8 with US scph-101 BIOS -Only Japan licenced game works. -I have tried Stealth 2.8a (J), Old Crow V2 for 12f629 (multi version and SCEI version) and get nothing. ### -Was I wrong to use SCPH-101 BIOS on PU-8? Might it be the cause of the not working modchip? -Should I replace whole MECHACON (and use 101 or 1002 boards as donors) to make it work? What MECHACON is? I replaced SC4309 japan to europe chip and the PS1 was failed to boot, so I discard the changes. -I really don't understand the main rule of using the modchip with different PS1 revisions. I mean - what is the main piece of PS1 hardware the chip must be adapted? Chip is adapted to its BIOS version, MECHACON or mainboard version? Cause I failed to use chips that should work on PU-8, so, I want to find out the moment where I made the mistake.
The modchip region needs to match the MECHCON. PU7 and PU8 boards work differently and do not have the signal MM3/Mayumi use to work with stealth games. Stealth 2.8a has "modes" you can enable by holding reset that make stealth games work by using a timer to disable the chip. Mayumi v4 and MM3 will both work with a PU7 and PU8, just without stealth support. The only thing I would change in your setup is to use a USA bios that isnt the PSone (slim). Otherwise, your setup is proven to work (I have personally done it, but I used a Phat USA bios, not the PSone). Also post pictures of your install, just to rule out something silly (swapping wrong chip instead of bios etc)
Here they are: I already tried to use instead of original SCPH-5000 BIOS these: 101, 102, 1002, 7002. They all works, (Jap) license work, other regions and all copies does not. PS1 can see them but mark them as "NOT PlayStation format disc, please insert original..." One Europe demo disc it even recognize as music with 10 tracks on it. So, the main problem is to make chip work, I find out that there are Multimode v2 that might work on PU-7 and PU-8. http://users.libero.it/enrico.zaniboni/immagini_installazione_multimode_2_7_fili.htm I have a few empty 12C508, so, should I try these firmwares? It does not matter if chip is not stealth, most games has no libcrypt. All self-made CD-R discs works fine on other console - PSOne. P.S. There was no chip, it was empty when I made photo. Its classic 4-wire: 1-power, 5,6- data bus (i think its called), 8-ground P.P.S. Yes, I know that the BIOS is a 32-pin chip between Parallel port and CXD8606Q
If the console can play jap cdr, the Modchip is working. You do not need to try different modchips. If you can't play jap cdr, there is an issue with the Modchip. But any Modchip should work with no stealth. If no cdrs work, sounds like a Modchip programming issue or installation issue (maybe bad install diagram?)
I took another scph-1002 PS1 console as base, put there second oscillator, bought new 12F629 chips in SOP-8 package and used the Old Crow v2 firmware. It works. Seems the problem with the first PS1 I mod may be with BIOS or chip flashing as you said. Thank you, I am happy to have at least one console complete, the first one need more time to spend. Next will be the HDMI mod, I will attempt to install there RGB SCART->HDMI converter from Aliexpress. Should work). P.S. I have one little question - I have PU-8 and PU-18 boards without oscillator (53.20 or 53.69), so, these PS1 should work if I will use RGB SCART points as signal source? Seems RGB SCART on PS1 is original signal and no need oscilator at all (I think so at least), the oscilator only need to form NTSC or PAL composite signal. Am I right?
Yes, if you use rgb you don't need the extra oscillator. It's only for pal or ntsc colour encoding, which when using rgb isn't used.
