LG RH188H Service Manual page 15

No 5V for HDD &
DVD Drive
YES
NO
Is there about 5.5V
at the IC156 pin1?
YES
NO
Is there about 4V ~ 5V
at the IC156 pin 4?
YES
Check the IC156
and Replace
Check D125 and
Replace
Check the 'PWR CTL
"H"' signal from µ-COM
No 12V for HDD &
DVD Drive
YES
Is there about 13.5V
at the IC155 pin1?
YES
Is there about 4V ~ 5V
at the IC155 pin 4?
YES
Check the IC155
and Replace
3-3
NO
Check D124 and
Replace
NO
Check the 'PWR CTL
"H"' signal from µ-COM