MikroTik RB800r2v5 Operating instructions

No power, blue LED doesn’t shine
The board is unrepairable
Check D20, Q4
NOT OK
OKOK
Problem still appears
TroubleShooting for R 800r2v5
PoE doesn’t work
Check bridge rectifiers D17, D21
NOT OK
Check Zener diode D19, D22 and 3V
under vo tage detector U21
NOT OK
Check N-channe MOSFET Q7
NOT OK
Check N-channe MOSFET Q9, Q10
NOT OK
Check power contro er U22
NOT OK
OK
OK
Change fau ty D20, Q4
Change fau ty MOSFET Q7
Change fau ty MOSFET Q9,
Q10
Change fau ty contro er
U22
Change fau ty D17, D21
Change fau ty D19,D22,
U21
Check N-ch MOSFET Q5
Change fau ty MOSFET Q5
OK
NOT OK
The board is unrepairable
Problem still appears
Check resistor R273. It resistance
shou d be 10 Ohm.
NO 10 Ohm
Change fau ty resistor R273
Change fau ty Q6
Check NPN transistor Q6
OK
OK
NOT OK

Doesn’t boot, blue LED is ON
NOT OK
OK
NOT OK
The board is unrepairable
NO 1.8V
Problem still appears
Check 66.666MHz c ock on Y1
pin#3
Check 1.8V output, for
examp e on C451
Check CPU core vo tage 1.0V
output, for examp e on C435 pins
NOT OK
NOT OK
OK
Check DC-DC step down
converter U27
Change fau ty U27
Check Q12, Q13, U26
Change fau ty Q12, Q13,
U26
Change fau ty osci ator
Y1
Check ferrite bead FB8. It
resistance shou d be ess
than 1Ohm.
Change fau ty ferrite
bead FB8
NOT OK
OK
Check LDO U25
Change fau ty U25
NOT OK
OK

Ethernet1 doesn’t work, drops ping packets
Check transformer TR1
The board is unrepairable
NOT OK
NOT OK
OK
Problems still appears
OK
Check ferrite beads FB4, FB5.
Ferrite beads resistance shou d
be ess than 1 Ohm
OK
Check Ethernet c ock 25MHz
on crysta Y4
NO 25MHz
OK
NOT OK
Check 1.2V output, for examp e
on C168
Check resistors R152, R153,
R154, R155 resistance. It
shou d be 75Ohm +/-1%
Change faulty resistors
Change fau ty TR1
Change fau ty U28
NOT OK
OK
Change fau ty FB4,
FB5
Change fau ty Ethernet
PHY U18
Change fau ty crysta Y4
Check vo tage drop on
D5, D8 pin#1 and ground.
It shou d be in the range from 0.3V to 0.4V measured
in diode mode (ho d “positive” wire on the ground and
“COM” wire to
D5 pin#1) or you can unso der diode arrays D5, D8
and try to send traffic over Ethernet port. If traffic goes
through port it means that diode arrays was defective
Change fau ty D5, D8
NOT OK
OK
Check ferrite bead FB9. It
is resistance shou d be
ess than 1Ohm
OK
NOT OK
Change fau ty ferrite
bead FB9

Ethernet2 doesn’t work, drops ping packets
NOT OK
Change fau ty connector J13
and Gigabyt Ethernet PHY
U19
Check termination resistance between Tx
and Rx in the connector J13. The
resistance shou d be 150Ohm +/-2%
Check vo tage drop on D9, D11 pin#1
and ground. It shou d be in the range
from 0.3V to 0.4V measured in diode
mode (ho d “positive” wire on the ground
and “COM” wire to D9 pin#1)
Change fau ty diode array
D9, D11
NOT OK
OK
Check ferrite beads FB6, FB7.
Ferrite resistance shou d be ess
than 1 Ohm
NOT OK
OK
Check 25MHz c ock on crysta Y5 pins
NO 25MHz
OK
Change fau ty ferrite
beads FB6, FB7
Change fau ty
crysta Y5
Change fau ty Gigabit
Ethernet PHY U19
OK
The board is unrepairable
Problem still appears

Ethernet3 doesn’t work, drops ping packets
NOT OK
Change fau ty connector J13
and Gigabyt Ethernet PHY
U19
Check termination resistance between Tx
and Rx in the connector J13. The
resistance shou d be 150Ohm +/-2%
Check vo tage drop on D1, D3 pin#1
and ground. It shou d be in the range
from 0.3V to 0.4V measured in diode
mode (ho d “positive” wire on the ground
and “COM” wire to D1 pin#1)
Change fau ty diode array
D1, D3
NOT OK
OK
Check ferrite beads FB2, FB13, FB14.
Ferrite beads resistance shou d be
ess than 1 Ohm
Check Ethernet c ock 25MHz on
R97 pins
OK
Change fau ty FB2,
FB13, FB14
Change frequency
generator U17
Change fau ty Gigabit
Ethernet PHY U16
Check Ethernet c ock
25MHz on crysta Y3 pins
NOT OK
Change fau ty Gigabit
Ethernet PHY U16
NO 1.6V
OK
Check 1.6-1.7V on C160 pins
OK
NO 25MHz NO 25MHz
NOT OK
The board is unrepairable
Problem still appears

MiniPCI-Express doesn’t work
NOT OK
Check 1.5V output, for
examp e on C464
NOT OK
OK
The board is unrepairable
Problems still appears
FAN doesn’t work
Check 5-7V, for examp e
on C433 pins
Check Schottky diodes
D28, D29
Check MOSFET’s Q2, Q3
Check TinyLogic invertor
U20
Check ferrite bead
FB11. Ferrite bead
resistance shou d be
ess than 1 Ohm
Change fau ty PWM
step down converter
U29
Change fau ty FB11
NO 5-7V
OK
Change fau ty D28, D29
Change fau ty Q2, Q3
Change fau ty U20
OKOK
NOT OK
NOT OK
NOT OK
Check 25MHz c ock on
crysta Y3
Change fau ty frequency
generator U17
Change fau ty FANCheck FAN
NOT OK
OK
NO 25MHz

When you order components for repairing router boards from our
sales, please, write components reference number not a part number
Reference
number
Part Number Manufacturer Description
TR1 15F-90NL Yuan Dean Scientific Co.,
Ltd
10/100/1000 Transformer with
PoE support
U16 AR8131-AL1E Atheros Technology Ltd. AR8131, QFN48-04MM, Gbe
NIC, PCIe, 3V
D17, D21 DF02SA-E3/77 Vishay Intertechnology,
Inc. ridge Rectifier, 1A 200V, DFS
J11, J13
F 4, F 6, F 14
R 1-216 AK1A U.D. Electronic Corp.
RJ45 Ethernet connector 10/100/
1000 , LEDs(G/Y), without springs
LM15AG121SN1D Murata manufacturing Co. Ferr Chip eads 120 Om
500mA, 0402, F 120
D1, D3, D5, D8, D9,
D11 AOZ8000CIL Alpha & Omega IC TVS ARRAY LOW-CAP SOT23-6
Q9, Q10 AO4484 Alpha & Omega
N-Ch MOSFET 40V 10A 10mOhm
SO-8
F 2, F 13 LM15AG121SN1D Murata manufacturing Co. Ferr Chip eads 120 Om
500mA, 0402, F 120
F 5, F 7 LM15PD121SN1D Murata manufacturing Co. Ferr Chip eads 120 Ohm
±25%, 1300mA, 0402
R273 ERJ-2RKF10R0X Panasonic
Resistor R10, 1%, 1/16W, 50V,
0402
Q4, Q5, Q7 FDD3682 Fairchild Semiconductor
[FSC] 100V, 32A, 36mOHM, 18.5nQ
Q12, Q13 AP4434GM Advanced Power
Electronics Corp.
N-ch MOSFET 20V 18.5mOhm
8.3A SO-8
U18, U19 AR8021-AL1E Atheros Technology Ltd. Single-port Gigabit Ethernet
(GbE) PHY device
D20 ZX84C10/SOT23-GP SINYORK CO., LTD. Zener Diode ZX84C10 SOT23
D28, D29 FM2100/SMA-GP SINYORK CO., LTD. Diode Schottky FM2100
Vf=0.85V Vr=100V If=2A SMA
Q2, Q3 2N7002,215 NXP Semiconductors TRENCH MOSFET, SOT23
R152-R155 RC0603FR-0775RL Yageo Corporation
Resistor 0603 75,0R 1% 0,1W
U17 ICS9FG108DGLFT IDT
Frequency Generator for CPU,
QPI, F D, PCIe & SATA, TSSOP48
U20 NC7S04M5X Fairchild Semiconductor
[FSC] 1 TinyLogic HS Inverter
D19 ZX84C6V8LT1G ON Semiconductor Diode Zener ZX84C 6.8V 5.9%
225mW SOT23
F 8, F 9 LM18PG331SN1D Murata manufacturing Co. Ferr Chip eads 330 Om
1200mA, 0603
F 11 RC1608J000CS Samsung Electronics Co. Resistor 0R 5% Jumper 0603
D22 ZX84C6V8LT1G ON Semiconductor Diode Zener ZX84C 6.8V 5.9%
225mW SOT23
Q6 CP56-16T1G ON Semiconductor NPN Silicon Epitaxial
Transistor

When you order components for repairing router boards from our
sales, please, write components reference number not a part number
Reference
number
Part Number Manufacturer Description
U21 LMS33460MGX/
NOP
NATIONAL
SEMICONDUCTOR [NSC]
3V Under Voltage Detector
(lead free)
U22 LM5020MM-1/NOP NATIONAL
SEMICONDUCTOR [NSC] Power Controller MSOP10
U25 RT9183HPS Richtek Technology
Corporation 1.5A Adj LDO SO8
U26 TPS40009DGQ Texas Instruments 600kHz, 2.25-5.5Vin/0.7-5.0Vout
U27, U28 RT8011APQW Richtek Technology
Corporation
DC-DC Step down converter,
WDFN-8E
U29 RT8010APQW Richtek Technology
Corporation
High Efficiency PWM Step-
Down DC/DC Converter
Y1 NAOD66.666-C3C NSK Jenjaan Quartek
Corporation Crystal oscillator 7*5, +/-30PPM
Y3, Y4, Y5 NXE25.000AC20F-
AHF
NSK Jenjaan Quartek
Corporation 25Mhz Crystal

R 800r2v5 Reference picture

R 800r2v5 Reference picture