Sharp GX20 Service Manual page 59

YES
YES
YES
Only main display back light
or both displays' back lights.
YES
YES
YES
NO
YES
YES
YES
NO
NO
NO
H
NO
→
NO
When the external display
back light does not light up.
NO
NO
YES
NO
NO
NO
NO
YES
→ →
YES
(To page 2-54)
H
NO
YES
NO
YES