Texas Instruments Extensa 660 Series Maintenance Manual page 86

PRESS POWER
DC-IN = 20V
YES
5V
Check CN33 PIN4
0V
YES
5V
0V
YES
Figure 5-10 DC/DC Converter Interface Troubleshooting Diagram
5-26 Troubleshooting Procedures
9
System Fails to Boot:
DC/DC Converter Interface Checks
SWITCH
Check T3, F1, D12,
NO
D11, F2, Q5, D14
BAT = 12V
YES
NO
SW2 = 5V
NO
for low pulse
NO
U1, PIN 7
END
Check M/B
Check SW2
Check D29, D2, D3, U2,
Q1, Q2, Q3, Q4, C14, R13,
R14, D4, D5, R8, R9, R10,
R11, R1
Check SW1