Haier HL42B-B, Service Manual

Page: 53 / 60

54
First, check cables which connect with PSU
，
then check as follows
1) Check input voltage
voltage: +5VSB
→ POWER ON(5V) → +12V → 5V
connector: CN4(P1) → CN4(P13) → CN5(P1,P2,P3) → CN4(P2,P3,P4,P5) → CN4(P12) → CON4(P14)
2)Check output voltage
voltage: Vblon
→ +5V → Vipwm
connector: CN4(P12) → J28(P26-P30) → CON4(P14)
CN4 CN5
ON - 2.0 - 5.0 V On/Off Control
Voltage
OFF
V
BLON
- 0 - 0.8 V
MAX 3.0 3.15 3.3 V Maximun duty ratio Internal PWM
Control Voltage
MIN
V
IPWM
V
SEL
=L
0 - V Minimum duty ratio