LG / GOLDSTAR RH1858
Service Manual

No SW_12VG
YES

No SW_FD(+)
YES

Is the VCC (14V) supplied to Q165 Collector?
YES

NO

Check D124 on SMPS Board and Replace

Is the VCC (FD+) supNO plied to Q163 Collector ?
YES

Check D121 on SMPS Board and Replace

Is there about 12.5V at NO ZD152 & Q165 Base?
YES

Check Q165 and Replace

Is there about 5.3V at R184 and Q153 Collector ?
YES

NO

Check Q163 and Replace

Is the VCC (33V) sup- NO plied to Q160 Emitor?
YES

Check D126 on SMPS Board and Replace

Is the VCC (5.3V) supplied to Q153 Emitor ?
YES

NO

Check 5.3VA on SMPS Board

Is there about 0V at NO Q160 Base?
YES

Check Q160 and Replace

Is there about 0V at Q153 Base ?
YES

NO

Check the �STANBY H� signal from µ-COM

Is there about 5.3V NO at Q166 Base?
YES

Check SW_5.3VA

Check Q153 and Replace

Check Q166 and Replace

No 1.8V
YES

No 1.25V
YES

Is the VCC (3.3V) supplied to Q159 NO Emitor And IC154 pin 1,2,8 ?
YES

Check 3.3V power supply

Is the VCC (2V) supplied NO to Q154 Emitor ?
YES

Check D155 and 2.5V power supply

Is there about 3V ~ 3.3V at Q159 Base and IC154 pin 3 ?
YES

NO

Check Q159 and Replace

Is there about 2V ~ 2.5V at Q154 Base and IC154 pin 4?
YES

NO

Check Q159 and Replace

Check IC154 and Replace

Is the VCC (3.3V) sup- NO plied IC154 pin 1,2,8 ?
YES

Check 3.3V power supply

Check IC154 and Replace 3-6