PAL PS1s , PU-18 and PU-23 revisions, modchip info and recomendations needed

Hiya!

today I took a look at the 3 PS1s I have in order to ensure they are OK.
2 of them are SCPH-9002 models , both PU-23 mobos - both chiped
1 is the older SCPH-5552 model with the parallel port, PU-18 mobo - currently not chiped

I remember I have installed a 8-wire mod on one of the PU-23 mobos, so it works fine with imports, backups, originals. Not gonna bother with it since it's OK as far as I can tell.

The other PU-23 ps1 has this pre-installed mod , it's a 3-wire install (?) plus a jumper cable, no idea what it is. I assume it does not boot imports?




Anyone has any recommendations on what to reflash/reinstall on the PU-23 mobo? And what mod to install on the PU-18 one?
Thanks in advance for any info/help

 

Its a 4 wire install, the ground connection just is soldered directly without a wire.

So its probably old crow and will boot imports, just not stealth protected games.

If you are going to replace the chip, mayumi v4

 

thanks, I'll replace it for sure... so it's mayumi for both 5552 and 9002 , right?

 

yes

 

bleh, didn't pay attention to the chip and it's a 528A , which means an OTP device... I tried to erase it (when I thought it was a 528) and now on the sequential readings I think I see different data, I am pretty sure I read SCEI/SCEE/SCEA on the code before... sadly my other 2 PICs are of the A variant as well...

btw, is there a Mayumi v4 feature list? why is it better than others?

 

Mayumi v4 is similar to MM3, but it uses clock signal from the PS1 itself, which is more accurate than the internal osc.

For the sake of 1 extra wire, I just install Mayumi's now.