Texas Instruments 660 - Manual (Page 86)

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