Bitmain APW12 upgrade
For using PSU in overclocked miners
Method 1: Add two resistors in FAN IC circut and wire jumper
Step 1
Prepare PSU and parts for upgrade. And soldering tool. Hot air station.
Step 2
For upgrade, you need to use two resistors 1206 size. Nominals of 56 Ohm 5% and 4.3 Ohm 1% and wire jumper
Step 3
Disassemby PSU. Remove the top cover, carefully unscrew the board from the bottom of the case. Caution High voltage capacitors can be electrocuted if not discharged.
Step 4
Carefully turn the board over and find the area where you need to add resistors
Step 5
Locate near FAN IC two 1206 size resistors, on top of which you need to solder additional
Step 6
Add flux
Step 7
Use hot air station for add first resistor 56 Ohm.
Step 8
Add second resistor 4.3 Ohm.
Step 9
Locate near PIC IC 0805 size resistors R126. Resistor 1 kOhm. Can be marked as 01B or 01H or 102.
Replace resistor or just add wire jumper as on pictures Step 9 or Step 10.
Step 10 
Finish
Now you must assemble PSU in back order.
Step 3
Disassemby PSU. Remove the top cover, carefully unscrew the board from the bottom of the case. Caution High voltage capacitors can be electrocuted if not discharged.
Step 4
Carefully turn the board over and find the area where you need to add resistors
Step 5
Locate near FAN IC two 1206 size resistors, on top of which you need to solder additional
Step 6
Add flux
Step 7
Use hot air station for add first resistor 56 Ohm.
Step 8
Add second resistor 4.3 Ohm.
Step 9
Locate near PIC IC 0805 size resistors R126. Resistor 1 kOhm. Can be marked as 01B or 01H or 102.
Replace resistor or just add wire jumper as on pictures Step 9 or Step 10.
Step 10 Finish
Now you must assemble PSU in back order.