Play Station 1 - PSX

Today, I am back to my all hobby from years ago. That is PlayStation, 1 of my first consoles I played.
As described on  wikipedia, You guys would know that Sony has release hardware for all regions but locked other regions so you can only use CD from regions u bought.
I got this ps from my friend, seem case not original from Sony.

AT back of this PS give me SCPH-9001, but after open the case it gaive me PU-20 board.

 This PU-20 board as show in wiki is SCPH-700x model, haha how they put SCPH-700x board in a 900x case? So this is modified version.
Lets take more photo after open iron case:

Oh here is the mod chip as I searched before: 12C508, this psone is hacked version. But it look undocument  when searching on web, darn!

So I wipe them out and try another opensource solution: PSnee

How to connect diagram:

Pin assignments
                    
       PSNee psxdev                   PlayStation
  Arduino   Atinny  name           ps pin         Name

  pin-vin  = VCC    = 3.5v         3.5v           = supply
             3      = debugtx
  pin-9    = 4      = gate_wfck    IC732.Pin-5    = WFCK        5 - gate   
  pin-8    = 2      = data         IC732.Pin-42   = CEO         6 - data
  pin-7    = 1      = subq         IC304.Pin-24   = SUBQ
  pin-6    = 0      = sqck         IC304.Pin-26   = SQCK
  pin 5             = BIOS D2      IC102.Pin-15   = D2
  pin 4             = BIOS A18     Ic102.Pin-31   = A18
  Pin-Gnd  = GND    = gnd          GND            = gnd

Diagram above a get from PSnee github, if u dont care too much about all pins. just take care these pins:
VCC
pin-9
pin-8
GND
After digging more posts I can find more photos and  

 This photo from http://modchip.aeug.org/install/508-pu20-stealth.html
Lets translate to our language from website author:

1 - Vdd
4 - reset switch
5 - gate
6 - data
7 - door switch
8 - Ground

PlayStation
ps pin         Name
3.5v           = supply

IC732.Pin-5    = WFCK        5 - gate   
IC732.Pin-42   = CEO         6 - data
IC304.Pin-24   = SUBQ
IC304.Pin-26   = SQCK
IC102.Pin-15   = D2
Ic102.Pin-31   = A18
GND            = gnd

Here is IC 304, for the stealth we need to find out pin 24 and pin 26 of IC 304