MikroTik RB800r2v5 Troubleshooting Manual

TroubleShooting for RB800r2v5
No power, blue LED doesn't shine
Check D20, Q4
Check N-channel MOSFET Q7
Check N-channel MOSFET Q9, Q10
Check resistor R273. It resistance
should be 10 Ohm.
Check NPN transistor Q6
Check power controller U22
Check bridge rectifiers D17, D21
Check Zener diode D19, D22 and 3V
under voltage detector U21
Check N-ch MOSFET Q5
NOT OK
NOT OK
NOT OK
NO 10 Ohm
Problem still appears
The board is unrepairable
PoE doesn't work
Problem still appears
The board is unrepairable
Change faulty D20, Q4
Change faulty MOSFET Q7
Change faulty MOSFET Q9,
Change faulty resistor R273
NOT OK
Change faulty Q6
NOT OK
Change faulty controller
NOT OK
Change faulty D17, D21
NOT OK
Change faulty D19,D22,
NOT OK
Change faulty MOSFET Q5
Q10
U22
U21