Service manual

VE-CG30U
VE-CG40U
19
6.TROUBLESHOOTING
Power circuit troubleshooting
Power does not turn on.
Yes
Battery input
Check battery, battery terminals,
F2902, FB2901, FB2902, IC2901,
and R2901 - 2904.
Which is used, battery or DC input? When using DC input, does power turn on with battery?
DC input
Yes
Check AC adapter, DC jack,
FFC connection bet. JACK
PWB and MAIN (improper
insertion), F2901, and D2902.
When using battery, does power turn on with DC input?
No
No
Yes
Is P-CON-H sent to IC1901 6PIN?
Is 3.3V applied to TL7901?
Check soldering of IC702 33PIN and
IC1901 6PIN.
Check R1926.
Yes
Yes
No
Is triangular wave delivered to IC1901 7PIN even
for a moment?
Check IC1901 8PIN and
9PIN soldering, R1906, and
C1902.
No
Yes
Is pulse delivered to IC702 40PIN?
Check IC7901, C7901, and C7902.
No
Is voltage applied to D3901 cathode?
Check D3901, L3901, and
Q3901.
Yes
Yes
No
No
When Power SW is pressed, IC702 (43) pin falls
to "L".
Check IC702 40PIN and 41PIN, and
FL701.
Is 1.8V applied to TL6901 even for a moment?
Check Q6901, L6901, and
L6902.
Yes
No
No TOP PWB: Check power SW, connector and
harness.
MAIN: Check SC202 and R706.
Is 3.5V applied to both ends of C4902 even for a
moment?
Check Q4901 and L4901.
Yes
Yes
No
Check IC4902, R4904, and
and IC702 34PIN.
Is 3.3V applied to TL4902 even for a moment? Failure inside IC702.
Yes
No
Is voltage (NONREG) applied to T5901 3PIN and
4PIN?
Check Q5901 and R5901.
Yes
No
Check T5901, D5902, C5904,
D5901, C5903, L5901,
C5911, L5902, and C5907.
Is 15V applied to both ends of C5904?
Yes
Though voltage is applied to all power lines, power
does not turn on (LED and LCD are not lit).
No
Check power lines again.
Yes
FL201 or IC204(ASIC) failure.
Is voltage (3V) applied to IC702 33PIN(P-CON-H) ?
No