I install a lot of RB750 without any problem.
The rb750r2 with exactly the same configuration have a high RMA. All exactly have the same symptom: all LEDs off, and is only accessible by pressing the reset button....

The setup is simple: Bridge over all ports, IP over the bridge, and a MAC bridge filter / filter. Nothing more ....
Even today, I upgrade 6.27 to 6.30.2 was the same ....all leds off, and RB750r2 dead...

I will not install more RB750r2 until this problem is solved (this problem did not exist with RB750)

indeed, I believe that the fatal error occurs when attempting reboot

We have tested hEX lite on our lab and have not managed to reproduce issue like one that you mentioned.

You mentioned that router is only accessible if you press reset button. Did you mean that you reset router or do you run backup bootloader?

Can you please send supout file to support@mikrotik.com with your configuration? It sounds like issue might be triggered with specific configuration so we need to see it in order to reproduce issue and after that fix it.

Thank you very much for answer.
I am not able to access the router after the fault by IP address (mac telnet and mac winbox are always disabled in my configuration, but the LEDs are off when it fails, so I think that is impossible to access, I do not know...)

To get access again, I push the back button to restore factory settings. It's the only way I found.

I can not generate the supout.rif because I can not access the router, but if I can send you an identical supout.rif from a router that is working with exactly the same configuration.

Now I have here a router with this problem. I do not have access (all leds off). Do you wish to do some testing with it? (I do not know how). I am very interested to solve this problem, I can try send you the router (for free) if you give me an address.

Note.- All untis have 6.27 when fail.

The config that I use is:
(executed under default configuration)
/interface set 0 name=ether1
/interface set 1 name=ether2
/interface set 2 name=ether3
/interface set 3 name=ether4
/interface set 4 name=ether5

/interface ethernet
set [ find default-name=ether3 ] master-port=none
set [ find default-name=ether4 ] master-port=none
set [ find default-name=ether5 ] master-port=none

/interface bridge
add mtu=1500 name=bridge1
/ip neighbor discovery
set ether1 discover=no
set ether2 discover=no
set ether3 discover=no
set ether4 discover=no
set ether5 discover=no
set bridge1 discover=no

/interface bridge filter
add chain=forward disabled=yes in-interface=ether2 out-interface=ether1 src-mac-address=00:00:00:00:00:00/FF:FF:FF:FF:FF:FF
add chain=forward disabled=yes in-interface=ether3 out-interface=ether1 src-mac-address=00:00:00:00:00:00/FF:FF:FF:FF:FF:FF
add chain=forward disabled=yes in-interface=ether4 out-interface=ether1 src-mac-address=00:00:00:00:00:00/FF:FF:FF:FF:FF:FF
add chain=forward disabled=yes in-interface=ether5 out-interface=ether1 src-mac-address=00:00:00:00:00:00/FF:FF:FF:FF:FF:FF
add action=drop chain=forward disabled=yes in-interface=ether2 out-interface=ether1
add action=drop chain=forward disabled=yes in-interface=ether3 out-interface=ether1
add action=drop chain=forward disabled=yes in-interface=ether4 out-interface=ether1
add action=drop chain=forward disabled=yes in-interface=ether5 out-interface=ether1
add chain=forward in-interface=ether1
add chain=forward out-interface=ether1
add action=drop chain=forward
add action=drop chain=input disabled=yes in-interface=!ether1

/interface bridge port
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=ether2
add bridge=bridge1 interface=ether3
add bridge=bridge1 interface=ether4
add bridge=bridge1 interface=ether5
/ip firewall connection tracking
set enabled=no
/ip address
add address=172.16.0.100/20 interface=bridge1 network=172.16.0.0
/ip dns
set allow-remote-requests=yes servers=172.16.0.1
/ip route
add distance=1 gateway=172.16.0.1
/ip upnp
set allow-disable-external-interface=no
/snmp
set trap-community=public
/system watchdog
set automatic-supout=no
/system clock
set time-zone-autodetect=no
/system clock manual
set time-zone=+02:00
/system identity
set name="Switch RB750 172.16.0.100"
/system ntp client
set enabled=yes primary-ntp=188.40.42.71 secondary-ntp=185.18.149.149
/tool mac-server
set [ find default=yes ] disabled=yes
add disabled=yes interface=ether2
add disabled=yes interface=ether3
add disabled=yes interface=ether4
add disabled=yes interface=ether5
set 0 disabled=yes
set 1 disabled=yes
set 2 disabled=yes
set 3 disabled=yes
set 4 disabled=yes
/tool mac-server mac-winbox
set [ find default=yes ] disabled=yes
add disabled=yes interface=ether2
add disabled=yes interface=ether3
add disabled=yes interface=ether4
add disabled=yes interface=ether5
set 0 disabled=yes
set 1 disabled=yes
set 2 disabled=yes
set 3 disabled=yes
set 4 disabled=yes

/ip dhcp-client remove 0
/ip dhcp-server remove 0
/ip dhcp-server network remove 0
/ip pool remove 0
/ip firewall nat remove 0
/ip service set www disabled=no
/ip address remove 0

How do you perform upgrade? Do you use "/system package update" or do you simply upload/download file to router and then reboot it?

I did just test your configuration and router works after upgrade without any problems for me.

Is there something else what you might have forgotten to say about this configuration?

Hi,
I use /system package update, because this router was installed in a client.

There is no more relevant information.... I just upgrade and reboot... and then it die with all leds off.
One script that I cut in the previus script, was a reboot every four days (and I think that others routers die at reboot, but I can not be sure)

All routers have 6.27 and routerboard firmware updated.
If I push reset button to get default configuration, the router can be used again without problems, it's mean, the router is not damaged

Once installed, I only access to the router to:
- Enable or disable ether ports (to add or delete customers access)
- Set mac address in bridge filter to allow only router mac address of the customer
and just this. There is no other uses.

I use winbox to access. In a first step I use Chrome, and when I see that is RouterOS (and not SWOS), I close Chrome and use Winbox only (old Winbox version)

Hi,
I have news. This week has died two rb750r2. Neither has been recovered with the reset button. They definitely dead. But one of them we know why:

First one:
It was powered by poe in ether1. Power contacts in RJ45 POE works perfectly, but data contacts of POE was wrong. That is, the link: on/off/on/off/on/off.... That killed the RB750vr2. Now the USR is: off/ a bit on / fully on. Changes in these three states.

The second:
The USR light is always off, and we don't know why fail.

Reset button, has no effect....

Until now:
0 units fail RB750 / RMA (I have many installed)
6 units fail RB750vr2 / RMA (I have only installed a few)
(identical use and configuration)

Hi,
I have news. This week has died two rb750r2. Neither has been recovered with the reset button. They definitely dead. But one of them we know why:

First one:
It was powered by poe in ether1. Power contacts in RJ45 POE works perfectly, but data contacts of POE was wrong. That is, the link: on/off/on/off/on/off.... That killed the RB750vr2. Now the USR is: off/ a bit on / fully on. Changes in these three states.

The second:
The USR light is always off, and we don't know why fail.

Reset button, has no effect....

Until now:
0 units fail RB750 / RMA (I have many installed)
6 units fail RB750vr2 / RMA (I have only installed a few)
(identical use and configuration)

You can try to see if your device is damaged by overvoltage. See the this PDF file for instructions (the file is usually provided to distributors)

http://www.mikrotik.com/download/share/ ... _08_06.pdf

I used a passive poe + original 12v RB750r2 power adapter.
I test power adapter, and it's OK

Finally, the RJ45 cable was OK, the fault was in previus 260GS, that don't work well, and all ether ports of this switch was wrong with continues link on/link off, and in some way, kill the RB750r2

Every week, 1-3 RB750r2 dies.... all IN THE SAME WAY.

There is obviously a serious problem. Mikrotik not recognize the problem and does not give a solution.
How many warnings are required for Mikrotik to accept the problem?
Please .... a solution!

I've got the same problem! RB750r2 just died! All Leds OFF.

I reinstalled 260GS for avoid this. Mikrotik denies the problem so RB750r2 is not a option at this moment for me....

I also just had a horrible experience with the RB750Gr2. I powered it up and updated it to current firmware and bootloader.
I set it up for the client and powered it off. I arrived at clients and hooked up the Ethernet cables and applied power and only the PWR light came on. No beep or USR light or eth lights. Tried different power supplies with same result. I unplugged all of the Ethernet cables and retried and got it to boot once. I commanded a reboot from Winbox and then it went into a reboot loop. Then I managed to do a Netinstall but in the process the license was destroyed even though I had netinstall keep existing. So now if I can get it to actually do a bootup it has no license. Something is seriously wrong in the software or hardware and it really needs to be addressed.

Hi guys, I just ran into this - still investigating, but the device will power back up if you leave it unpowered for over a minute or two. then any reboot or power cycle following will reproduce the non-booting issue. I'll continue mucking around with it. EDIT: rb750gr2 here. network tech was just turning it into a bridge.

I have a mountain of broken rb750r2. Today one more fail.
My dealer knows this problem. It is general.

Mikrotik, will be honest tell us the problem, to identify and to replace the affected units installed in our customers...

factory reset it with reset button held down, mac-winboxed in and ensured was reset, presented with option to remove configuration, etc... still locks up after power cycle, only USR light shows up. Have to wait another 2 min or so to boot. Going to try netinstall if I can get it into that mode.

did we have any official response for the problems?
I need to buy many not expensive routers with 64ram and I thought it was great idea to buy this one but I am afraid I will not.

did we have any official response for the problems?
I need to buy many not expensive routers with 64ram and I thought it was great idea to buy this one but I am afraid I will not.

i only see a couple of user reporting issues

i think is a specific issue not with the equipment

i have some rb750gr2 working without problems

After much research, I know which is the reason.
The difference between my failed configuration, and others, is that I do a reboot every 3 days (scheduled) . If reboot is not done, I think it does not fail.

I think there is a random problem at boot the units.

I have 15 out of 40+ units that were used in a network deployment that have failed. Most of the units are turned into bridges on all ports. On most units ports 3 & 4 stop working and the units get replaced. We have a stack of failed units. Some have been thrown away. None have been RMA'd yet because of cost to do so versus value. My customer has decided to stop replacing hEX units with hEX units due to the repeating failures. My supplier has not noticed any batches of equipment failures with this product. All failed units present the same symptoms. Yes we did automatic package upgrades using winbox. Units configured and deployed fine. Today I found another hEX on my desk with a sticky note that says "port 3 dead".

Due to continued issues this client may end up asking me to deploy alternative brand hardware as we've bought nothing but routerboard for this project and I have more product hardware failure & wireless software performance issues in 2016 than in the last 12 years of Mikrotik deployments.

I agree with everyone in this post. rb750GR2 has a problem & I didn't cause it by resetting the unit and bridging all ports. I do that on a lot of boards. They worked for a month or two and then ports die randomly or they just start rebooting.

Don't see many RMAs? Its because its not worth the few bucks I spent initially (even after 10+ failures) its especially not worth it for what I charge to install this gear.

Please fix yourself Mikrotik. Your starting to look and feel like TPLINK. Thats an insult because TPLink is plastic junk that doesn't work that well.

8 of every 10 units failed in my network, and mikrotik don't fix it.... It is clear for me. Don't buy these model......

Very interesting, just had very similar problem with RB750r2, see post viewtopic.php?f=2&t=128304

Today, ALL my rb750r2 are die. No one survive.... more than 20 units....

i have the same problem, today i was updating the router 6.40 to 6.41 and after reboot all interfaces are dead on rb750r2 what should i do.......?

I am having the same problem. I found this thread because the LEDs on one of the RB750r2s we got didn't light when in use. They light when the unit is powered up, but when you plug a cable into a port and a connection is made, they stay dark. On a second RB750r2, they behaved the way they did on the older RB750s where the LED would come on with a network connection and blink with activity. A third RB750r2 died where even pressing reset could not bring it back and it was RMAed.

Really, after reading this thread, I'm not inclined to buy these any more.

Also, we're running 6.42.6 which we upgraded to by loading the firmware as a file and then rebooting. We do it this way because these units are usually installed in remote locations and we generally want a stable as opposed to the latest firmware. Netinstall is not an acceptable option 99% of the time.

I managed to solved the dead LED issue by going to the /system LED menu and creating entries for each LED on each ether and setting the type to interface activity.

After upgrading my newly purchased RB750r2 (hEX lite) to v6.45.1, the router has ceased to exist... MikroTik Routers and Wireless - Products: hEX lite

No contact via IP-Addr or MAC-Addr (using WinBox) - Nothing shows up when I press the "Refresh-button”.

I have tried to reset according to instructions RouterBOARD Troubleshooting - MikroTik Wiki - Nothing works !

When I hold the reset-button for 5 seconds (until it blinks) and then releases it the USR-LED stays ON !
(I note that this is different from how my RB750UPr2 (MikroTik hEX PoE lite) behaves).
When I attach the “internet-port” another MikroTik router, the USR-LED dims after approx 5 sec… then goes off briefly, then ON for about 15 sec, then dims again… this is repeated over and over again.

The LAN-port LED's do not even blink when you insert a cable, which is odd…
When connecting the “internet-port” to another MikroTik router it does not seem to ask for a client Address ?
...however the port-LED on the other router is blinking

Any suggestions to why this is happening ? I have several MikroTik routers that I have used and configured for several years, and have never seen this behaviour before buying the hEX lite.

The power-jack is rated for 24v - NOT 12v
The POE can accept 9-30 volts - so it can run on 12v
BUT may experience problems if there is power loss in cables
Recommend - Run it on 24v - either direct to power jack OR via poe
Ensure that the voltage is correct before updating / upgrading the RB

PoE Input : 8V-30V (Passive PoE)
Power Input: 24V 0.38A Power Supply

@easycoms: not only that you dug a dead thread (post last before your reply is dated in September 2019), you also posted incorrect information. Official product page of RB750r2 states that input voltage range is between 6V and 30V and explicitly defines same range for both power input methods.
Voltage specification of supplied power adapter (24V) does not change a bit of what I wrote above.