Doesn’t boot, green and blue LEDs are lit
Check 2.5V output, for
example, on C841 pins
NOT OK
Change faulty N-channel
MOSFET Q807
N
O
T
O
K
Check voltage on PWM controller
pin#7 (PGOOD). It voltage should
be 3.3V
NO 3.3V
O
K
Check PWM controller
U803
Check resistor R307
resistance. It resistance
should be 68KOhm.
OK
O
K
Check 40.000MHz clock on oscillator
Y301 pin#3
Change faulty oscillator
Y301
NOT OK
The board is unrepairable
Problem still
appears
OK
Change faulty RAM U201, U202
Check 1.2V CPU core output, for
example, on C848 pins
NO 1.2V
Change faulty ferrite bead
FB801
Check Step Down DC-DC
convector U806
Change faulty Step Down
convector U806
O
K
OK
N
O
T
O
K
N
O
T
O
K
Check ferrite bead FB801. It
resistance should be less than
1 Ohm
PoE doesn’t work
Check Schottky diode
D801
NOT OK
Change faulty diode
D801
O
K
Check Ethernet
connector J601
NOT OK
Change faulty
connector J601
The board is unrepairable
Problem still
appears
Check N-channel MOSFET
Q807
Summary of Contents for RB433r3
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