LG / GOLDSTAR HDRF899X
Service Manual

2. POWER SUPPLY ON I/O BOARD

No 12V
YES

No 5VT
YES

Is the VCC (14V) supNO plied to Q164 Collector?
YES

Check D124 on SMPS Board and Replace

Is the VCC (5.3V) sup- NO plied to Q155 Emitor?
YES

Check 5.3VA on SMPS Board

Is there about 12.5V at NO ZD151 & Q164 Base?
YES

Check Q164 and Replace

Is there about 0V at D152 and Q152 Collector?
YES

NO

Check Q155 and Replace

Is the VCC (33V) supplied to Q162 Emitor?
YES

NO

Check D126 on SMPS Board and Replace

Is there about 5V at R180 and 0.7V at Q152 Base?
YES

NO

Check the �TIMER H� signal from µ-COM

Is there about 0V at Q162 Base?
YES

NO

Check Q162 and Replace

Check Q152 and Replace

Is there about 5V at R171 and 0.7V at Q156 Base?
YES

NO

Check the �PWR CTL H� signal from µ-COM

Check Q156 and Replace

No 5.2V
YES

No 33VT
YES

Is the VCC (5.3V) supplied to Q151 Emitor?
YES

NO

Check 5.3VA on SMPS Board

Is the VCC (33V) supplied to Q161 Emitor?
YES

NO

Check D126 on SMPS Board and Replace

Is there about 0V at D153 and Q156 Collector?
YES

NO

Check Q151 and Replace

Is there about 0V NO at Q152 Collector?
YES

Check Q161 and Replace

Is there about 5V at R171 NO and 0.7V at Q156 Base?
YES

Check the �PWR CTL H� signal from µ-COM

Is there about 5V at R180 and 0.7V at Q152 Base?

NO

Check the �TIMER H� signal from µ-COM

Check Q156 and Replace 3-4

Check Q152 and Replace