MHC-V44D
27
SMPS Board Diagnosis Flow (2/2)
Check Bridge diode condition (diode mode)
Live and (-) = OPEN
Neutral and + (-) = OPEN
(+) and (-) = OPEN
OPEN is OK, SHORT is BROKEN.
Yes/No
Yes
No
Check MOSFET Q908, Q909
drain-source is SHORT?
Change new
F901, D902, R965, IC965
No
No
No
Yes
No
If R965 OPEN
If R914 is OPEN
The output from SMPS board check as below
NO001
Pin1, 4, 5 = 13.5V (Standby, Demo, Power On)
NO002
Pin7-11 = 36V (Power On), 0V (Standby & Demo)
END
Yes
A
Check IC965, pin1-2 short?
Yes
Replace SMPS board if it is not up to standard.
Change new
F901, D902, R914, Q908, Q909
OPEN - broken
SHORT - OK (less than 1ohm)
Check Main Fuse F901 is OPEN?
Check fuse resistor
R914, R965 is OPEN?
OPEN - broken
SHORT - OK
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