service power suply Extreem 500w

Bismillah,
Gejala kerusakan pasien ini adalah semua output tegangan Ok,normal semua,kipas juga berputar.Akan tetapi tidak dapat menyalakan mother board.setelah kutelusuri ternyata tegangan POR pada pin no 8 kabel abu abu tegangannya tetap nol ketika PSon (hijau) di short kan dengan Ground. setelah kutelusuri,kutemukan IC Op amp LM339 dalam kondisi rusak.kuganti dan kucoba pada mobo,dan berhasil.Alhamdulillah.berikut ini deskripsi dari pin pin power suply ATX 20 pin.

Pin	Name		Color	Description
1	3.3V		Orange	+3.3 VDC
2	3.3V		Orange	+3.3 VDC
3	COM		Black	Ground
4	5V		Red	+5 VDC
5	COM		Black	Ground
6	5V		Red	+5 VDC
7	COM		Black	Ground
8	PWR_OK		Gray	Power Ok is a status signal generated by the power supply to notify the computer that the DC operating voltages are within the ranges required for proper computer operation (+5 VDC when power is Ok)
9	5VSB		Purple	+5 VDC Standby Voltage (max 10mA) 500mA or more typical
10	12V		Yellow	+12 VDC
11	3.3V		Orange	+3.3 VDC
12	-12V		Blue	-12 VDC
13	COM		Black	Ground
14	/PS_ON		Green	Power Supply On (active low). Short this pin to GND to switch power supply ON, disconnect from GND to switch OFF.
15	COM		Black	Ground
16	COM		Black	Ground
17	COM		Black	Ground
18	-5V		White	-5 VDC (2002 v1.2 made optional, 2004 v2.01 removed from specification)
19	5V		Red	+5 VDC
20	5V		Red	+5 VDC