Ingeniero

TroubleShooting for RB411r3v1
No power, blue LED doesn’t shine
NOT OK

OK

Check diodes D801

Change faulty diode

NOT OK

NOT OK

Check Zener diode D804

Change faulty
componentsOK

Check D802, Q802

NOT OK
Check P-channel MOSFET
Q801
OK

Change faulty Q801

NOT OK
Check N-channel MOSFET
Q804
OK

Change faulty Q804

NOT OK
Check PWM controller U802.
Onthe pin#1 should be 4.4V-5V.
OK

Change faulty U802

NO 10 Ohm
Check R813.
It should be 10 Ohm
OK

Change faulty R813

NOT OK
Check N-channel Dual
MOSFET Q805
OK

Change faulty DualMOSFET Q805

Check short circuit on 3.3V,
for example on C819

Problem still appears

The board is unrepairable

Doesn’t boot, green and blue LED’s is shine
NOT OK

Check 2.5V output, forexample on C815

NOT OK

Check N-channel MOSFET
OK
Q804

OK

Change faulty MOSFET
Q804

NOT OK

Check ferrite beads FB803,
FB802. It is resistance
should be less than 1 Ohm.

OKChange faulty U803

OK

NOT OK

Check CPU core voltage 1.2V
output, for example on C838

Change faulty ferrite beads

NOT OK

Check CPU 40MHz
clock on oscillator
Y301 pin#3

Change Y301Problem still appears

The board is unrepairable

Ethernet doesn’t work
NOT OK

Change faulty J601
connector

OK

Check termination resistance between Tx
and Rx lines in the Ethernetconnector
J601. It should be 150 Ohm +/- 2%.

NOT OK

Change faulty ferrite
beads FB602

OK

Check ferrite beads FB602.
It is resistance should be less than 1 Ohm.

NOT OK

ChangeEthernet
PHY U601

OK

Check resistance between D601 pin#1
and GROUND. This value should be in
the range from 0.4-0.5V measured in
diode mode (hold “positive” wire on the
ground and “COM” wire toD601 pin#1).

Check resistors R601, R612 . It is
resistance should be 1.5kOhm (R601),
2.4kOhm (R612)

NOT OK

Change faulty
resistors R601,
R612

Problem still appears

The board is...