MikroTik RB450G User Manual

Ethernet ports 2(J501), 3(J505), 4(J503), 5(J502)
do not work, drops ping packets
The board is unrepairable
Problem
still appears
Change faulty connectors
Check 1.0V output,
for example on C619
NO 1.0V
Change faulty transistor Change faulty ferrite beads
Check voltage drop between diode arrays D501-D506,
D509, D510 pin#1 and Ground. This value should be in the
range from 0.21V to 0.26V measured in diode mode (hold
“positive” wire on the Ground and “COM” wire to D501
pin#1)
Change faulty diode arrays and
6-port GbE Switch U501
NOT OK
OK
Check 1.5V output,
for example on C841 pins
Change faulty ferrite beads
NO 1.5V
OK
Check ferrite beads FB502-FB505 resistance.
It should be less than 1 Ohm
Change faulty ferrite bead
NOT OK
OK
Check termination resistance between Tx
and Rx lines in the each Ethernet connector.
It should be 150 Ohm +/- 2%
N
O T O K
OK
Check ferrite beads FB804, FB805
resistance. It should be less than 1 Ohm
NOT OK
OK
Change faulty DC-DC Step-Down
converter U807
Check PNP transistor
Q601
Check ferrite beads FB601,
FB602, FB604-FB607 resistance.
It should be less than 1 Ohm
Change faulty 6-port
GbE switch U501
Check 25MHz clock on
R541 pins
NOT OK
Change faulty Network processor
U1
OK OK
NOT OK NOT OK
OK

MikroTik RB450G Specifications

General

Wi-Fi band	-
Storage media	Flash
Internal memory	256 MB
Storage capacity	512 MB
Voltage monitoring	Yes
License level	5
Processor cores	1
Processor model	AR7161
Processor frequency	680 MHz
Compatible memory cards	MicroSD (TransFlash)
Basic switching RJ-45 Ethernet ports type	Gigabit Ethernet (10/100/1000)
Power over Ethernet (PoE) voltage range	8 - 30 V
Power connector	DC-in-jack
DC input voltage	8 - 28 V

Weight and Dimensions

Depth	115 mm
Width	90 mm
Weight	105 g