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TroubleShooting for RB433r3, RB433Ur2

These repair instructions are for NON WARRANTY 

repairs only!

No power, blue LED isn’t lit

Please make visual inspection for signs of corrosion or 

mechanical damages before starting.

Check Schottky diode D802

Change faulty diode D802

NOT OK

O

K

Check Zener diode D804

Change faulty components

Check PNP transistor Q802 and 

Zener diode D803

OK

O

K

NOT OK

Check P-channel MOSFET 

Q801

NOT OK

Change faulty P-channel 

MOSFET Q801

O

K

Check R819 resistor resistance. 

It should be 10 Ohm 

NO 10 Ohm

Change faulty resistor 

R819

O

K

Check PWM controller U803. 

On the pin#1 should be 4.4-

5.0V

NOT OK

Change faulty PWM 

controller U803

O

K

Check N-channel MOSFET’s 

Q806, Q808

NOT OK

Change faulty MOSFET’s

Check short circuit on 1.8V, 

for example, on C612 pins

O

K

Short circuit

Unsolder Ethernet Switch U601 

and check 1.8V for short circuit

O

K

Change faulty Ethernet 

Switch U601

The board is unrepairable 

Problem still 

appears

Summary of Contents for RB433r3

Page 1: ...D803 OK OK NOT OK Check P channel MOSFET Q801 NOT OK Change faulty P channel MOSFET Q801 OK Check R819 resistor resistance It should be 10 Ohm NO 10 Ohm Change faulty resistor R819 OK Check PWM controller U803 On the pin 1 should be 4 4 5 0V NOT OK Change faulty PWM controller U803 OK Check N channel MOSFET s Q806 Q808 NOT OK Change faulty MOSFET s Check short circuit on 1 8V for example on C612 p...

Page 2: ...cillator 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 OK OK NOT OK NOT OK Check ferrite bead FB801 It resistance should be less than 1 Ohm PoE doesn t work Check Schottky diode D801 NOT...

Page 3: ...ositive wire on the ground and COM wire to D601 pin 1 NOT OK NOT OK OK OK Change faulty Ethernet Switch U601 Check ferrite beads FB602 for J601 FB604 for J602 FB603 for J603 It resistance should be less than 1 Ohm Change faulty ferrite beads NOT OK OK Check 1 8V output for example on PNP transistor Q601 pins No 1 8V Check Q601 transistor NOT OK Change faulty Q601 OK Change faulty U601 OK Check 25 ...

Page 4: ...SOT23 R307 RC0402FR 0768KL Yageo Corporation Resistor 68k 1 0402 Q807 AOD480 Alpha Omega N Ch MOSFET 30V 25A 23mOhm DPAK Q802 BC856B 215 Philips AG Small Sign PNP 250mW SOT 23 Transistor Q801 AO4441 Alpha Omega P Ch MOSFET 60V 4A 100mOhm SO 8 FB801 BLM18PG331SN1D Murata manufacturing Co Ferr Chip Beads 330 Om 1200mA 0603 Q806 Q808 AO4484 Alpha Omega N Ch MOSFET 40V 10A 10mOhm SO 8 R819 ERJ 2RKF10R...

Page 5: ...RB433r3 Reference picture ...

Page 6: ...RB433r3 Reference picture ...

Page 7: ...RB433r3 Output Voltage picture ...

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