Modify circuit for Erase data W27Exxx ,W27Cxxx, SST27SFxxx

Figure 1. cut trace and add part

WinBond Chip (W27E512,W27E010,W27C010,W27C020)

1. Cut trace PCB U5A(pin 12) to ZIF32(pin 26) and add part figure. 1
2. Settting Vpp ~= 15V (diode dorp 0.7V) Real voltage to taget chip = 15-0.7 = 14.3V

- 1N4148 = 0.7V, 1N4001 = 0.6V

3. parallel R15(2k2) with resistor 15Kohm for increase Vpp(12.5V) to Vpe(14V) figure. 2
4. Run program Eprom.exe
5. Put CHIP W27xxxx,W27Cxxx
6. Select Device W27Exxx,W27Cxxx
7. short JPx (close)
8. click Icon Erase (It will Erase and check blank)
9. move JPx (open) and Resistor 15Kohm
10. check Blank again
11. load DATA
12. click Icon Program
13. End

SST Chip (27SF256/512/010/020)

1. Cut trace PCB U5A(pin 12) to ZIF32(pin 26) and add part figure. 1
2. Settting Vpp ~= 12.75V (diode dorp 0.7V) Real voltage to taget chip = 12.75-0.7 = 12.05V
3. Run program Eprom.exe
4. Put CHIP SST27SFxxx
5. Select Device SST27SFxxx
6. Short JPx (close)
7. Click Icon Erase (It will Erase and check blank)
8. Move JPx (open)
9. Check Blank again
10. Load DATA
11. Click Icon Program
12. End