Man, talk about bitter/sweet!! Why bitter? Because nothing sucks more than when a new product doesn't work right because of some crappy problem beyond my control with the manufacturering process. Sweet, well, we all know why we are here: the Mikrotik OS is awesome! I am still iearning it, but have come a long way in the last several weeks.

Anyways, I now have my 2nd bricked RB751U-2HnD Router out of 3 attempted installations so far. Symptoms: All lights and power flashing on/off very quickly. After the 1st one bricked, I posted questions about it here:
http://forum.mikrotik.com/viewtopic.php ... ts#p298504

So for safety sake since the 1st one bricked, I have been running the ones that I am going to do the new installs with here at the office. I upgraded the firmware to the lastest, which at the time of this post is v5.12, turned off the wireless, and just let it run with only the power plugged in. Except for playing around with it, I don't even configure them until I am onsite.

Once onsite, I plugged it in where I wanted it, looked at it from Winbox, clicked on the menu to reset the configuration, and on the reboot, it bricked. Very very disappointing. I had to get up very early to be onsite for this client for the installation. And stupid me did not think to bring spares with me, which I will definitely do when I return.

I have seen several places where folks were trying to be helpful and suggested a netinstall. But if you are fortunate enough to have not experienced this, it does not go into any kind of boot mode, because as soon as you turn it on, everything is flashing and that is all it does. "MikroTik Support" on here has said to go through the process of doing a RMA with the company I bought it from, which they in turn require a ticket # from Mikrotik. Someone else mentioned jacking up the power from 12V to 24V and it worked for them. But "MikroTik Support" again said it was a faulty board and really needed to be sent back in for warranty work. I did it on the 1st one and am doing it on the 2nd one now. But it sure is a slow process and I don't even have the 1st one back yet.

I am posting this as an informative post so others having this problem will know more about it. The best thing I can suggest is that if you are doing any type of work for clients and are using any Mikrotik stuff, buy extras! I bought 10 RB781's for 8 installs, one for the office and then 1 spare, and out of the 3 attempted installs, 2 have been duds.

Mikrotik Support says the problem was fixed right away and that most will never see this problem, with over 99% of the product working fine. That might be the case for some people, but the math does not add up in my case: 3 sites, 2 bad RB751's, 2 good RB751's, and still another visit needed for installing another new RB751 at the 3rd site. Right now, we're at 50% not working.

These guys really need to do 100% of QA on these known ones with issues. I am sure they know the S/N range of the potential bad ones and pull them from sellers and check them, or do something. I am trying to tell my peers in IT how great Mikrotik is, but this does not look good at all. I don't want a canned response from "MikroTik Support" saying we have already addressed this issue, because this issue is still affecting me today on January 26th 2012 on problems that were going on as far back as August of 2011 that I can tell from other posts. I had to wait over a month to recieve my product from Streakwave because they were waiting on new inventory to come in, which for me was around the end of December.

My intentions are not to bash Mikrotik here. But people need to know what is going on. And just as important, Mikrotik needs to give a little better answer than sharp replys with explanation points at the end of sentences about this and locking topics so no one else can respond to it, because I did go the extra mile and asked the additional questions. People do need to know that flashing units are bad and need to be RMA'd. But for a small business like me, I need the extra re-assurance of knowing what steps are being done to fix this and that it will not happen again. It is easy to sit behind a desk and tap away at a keyboard and get aggravated with users on a forum that are asking for help; a forum that is supported by paying users of products they have opted to buy instead of looking at open source options. And it is a whole another thing to be in the buyer's shoes, putting one's reputation on the line with a product that had some issues of some sort with either design or assembly.

I would love to be using Mikrotik for all of my clients where this is a good fit and am even more excited about the product than I was before. But like I said, I think we all need some better re-assurances than what has been given so far.

I don't think you're alone, there's been a lot of grumbling about the 751...

Yes, I agree. I know the mod is aggrevated with it. But you don't know aggrevation until you have backed out of 2 different jobs for loyal clients in two weeks time, and was not able to make your time billable either...

When we just had started production of this product, a few devices like this were found, we quickly fixed that problem and from then on, this problem will not happen to anyone. I am sorry that you got two of these first units. Please contact the seller for immediate exchange

When we just had started production of this product, a few devices like this were found, we quickly fixed that problem and from then on, this problem will not happen to anyone. I am sorry that you got two of these first units. Please contact the seller for immediate exchange

Thank you for your nice reply. I guess it is what it is sometimes. I will just keep my fingers crossed and will see how it goes next week when I put out some more from that order.

Have a good weekend.

When we just had started production of this product, a few devices like this were found, we quickly fixed that problem and from then on, this problem will not happen to anyone. I am sorry that you got two of these first units. Please contact the seller for immediate exchange

Thank you for your nice reply. I guess it is what it is sometimes. I will just keep my fingers crossed and will see how it goes next week when I put out some more from that order.

Have a good weekend.

For what it's worth, I've been installing around 30 of them in the last week, except from a dissapointing throughput on N (which I also mailed support for and still wait resolution), I had no issues or bricks on any of them.

Let's hope that when we continue upgrading our locations with them the coming weeks, my luck doesn't change
If it does, you sure will hear about it here.

I don't understand people claiming the device shipped with different power supplies the I see.
Mine all had a 12V 1A PSU default in the package.

Kind regards
B

justfishing,

I have the same problem over here, i sent my board to RMA and bought a 750 to try my config (w8 arrive), but i have a question, which version did yout board come from your reseller?

I was checking the forum looking for this problem, they said that they fixed the problem on last October, when the boards started to be shipped.

Thanks,

Regards,

Diego Ramos

Thanks a lot!

Today, it hit me. I have bought about 15 of these boxes in the last five month. All of them are working. I tried to switch my configuration from port “ether2” to port “ether1”. During changing the vlan settings, it bricked. You saved me a lot of time and I will send it back on Monday. Luckily, I have two boxes on spare

try with a power supply of 24 volt.

I had the same problem and solve it by changing the power supply.

I've tried that. I used the power supply of RouterBoard SXT G, which is 24V. Same led light show Nevertheless, thank you!

The same problem here. I bought my RB751U-2HnD yesterday 6.11.2012. Today, after 2 hours of configuring and testing it is bricked. The last configured part was wireless. Poor hardware...

Please return to seller for RMA replacement. RB751 with flashing LEDs must be replaced, there is no fix, changing to another type of PSU can revive it, but it will still not work the same as before.

When we just had started production of this product, a few devices like this were found, we quickly fixed that problem and from then on, this problem will not happen to anyone. I am sorry that you got two of these first units. Please contact the seller for immediate exchange (Posted: Fri Jan 27, 2012 10:42 am)

I am from Slovakia. I bought my unit in wholesale agem.sk on 6.11.2012 and tested it 7.11.2012. After 2 hours of configuring it was bricked. So I take it in to RMA on the same day. Now I am forced to wait up to 30 days for RMA. I can't do my work! But It's not my fault, It's yours!

I found a lot of articles about bricked B751U-2HnD on the internet. It's been about a year since you first time wrote about "some bad units from first batch". But it it's been a year man! All year round you are producing so many bad units?

The worst thing Mikrotik can do is not to tell anyone what is the problem and just say RMA. You need to understand that we are installing these devices and bad units costs us (and you) money and reputation.

I find it very hard to believe that all the 751U's bought over the last year are all part of "the very first devices". It's a very annoying and random problem it seems. The easy answer is "stuff breaks-send them back". But in my experience they can develop this problem at random and anytime. The answer Normis gave that if you power them up and they boot normally, don't worry, they are fine, is not correct. According to me it is lying.
I am more than angry! I want a quality product for which I paid and not so piece of junk with the function of accidental death...

What I wrote above is true. We fixed the the issue immediatelly after we started shipping the devices to USA, that was back in 2011.

A few weeks back, reports on the forum started to reappear, with similar issue. We have not yet confirmed the cause of these problems, but this is something else. We need to see those devices, that's why we are requesting you to contact seller for RMA.

To clarify again - units shipped during this whole year were working GOOD. These new reports in the forum are something new.

Dear all yes the router will work on 24v.but the problem still and it will come back again later. I fixed the problem permenantly on 12v.

I am serious, I found the solution and no need to replace the provided psu,it will take me just 20min to fix it,and it will be again as brand new, I fixed 8 unit in the last 2 month.the percentage of faulty units is 4.3% from our sold unit till now and it is moving up

I am serious, I found the solution and no need to replace the provided psu,it will take me just 20min to fix it,and it will be again as brand new, I fixed 8 unit in the last 2 month.the percentage of faulty units is 4.3% from our sold unit till now and it is moving up

Well, now what? You're going to put forward / share your findings, or just rant with it?

OK, I got it back from RMA. They gave me a new unit. I hope that it does not bricked again...

guess what? waste...

My "bricking" procedure in winbox was as follows:
RouterOS 5.16
- I have used the default settings. Then I exported them from terminal to text file. I changed all the network part of LAN IP adresses (find 192.168.88. replace 192.168.77.). Then I restored the factory settins with "no backup" and "no default settings" and in the terminal imported these settings. Then I changed the administrator password.
- Then I disabled the wireless interface (because of the safety at the time of configuration).
- Then I have created the pppoe client for my ISP connection.
- In the QuickSet on top of the main menu I have set the AP mode, custom SSID, Country Slovak republic, WPA2 AES password, hostname (router), ...
- Then I enabled the wireless interface and in 2 minutes was the RB751U-2HnD bricked.
-------------------------------------------------------------------------------------------
ok, I have used a more powerful powersource (12v 1,2A) and it WORKS! No country was saved in setting when it came alive. I will prefer to use the "Austria" settings rather...

Your distributor wanted to be good to you, and gave you a new unit from the same box. That box must have been returned to MikroTik for replacement. We are replacing all units with "flashing LED sindrome".

Dear all

Our's happen the same...all led blinking...I just power up and leave it on the whole day....after certain period that's RB751U going back to normal...We can configure it back as normal routerboard i.e through winbox, webfig etc....Just to ask mikrotik support...this device need to RMA???? Our shipment last October if updated by mikrotik all goods already resolve...why this device happen to us.

Please advise

Dear all

Our's happen the same...all led blinking...I just power up and leave it on the whole day....after certain period that's RB751U going back to normal...We can configure it back as normal routerboard i.e through winbox, webfig etc....Just to ask mikrotik support...this device need to RMA???? Our shipment last October if updated by mikrotik all goods already resolve...why this device happen to us.

Please advise

I would recommend to RMA any device which has shown "all blinking leds" issue, but is your device working good?

I wrote with the RMA department and they offered me an next one replacement. When I was there in person, they wanted me to pay back my money. They said it was a problem of mine. Reportedly no one else had no such a problem. So I told them about this forum...
Finally, I picked up a replacement piece and bought a more powerful power supply (24v 1,2A). No problem since then did not appear. I hope that it's been definitively resolved. It is annoying that with each new unit I will have to buy a more powerful power source, because I don't want to do a final quality controll of RB751U-2HnD units on side of the customer

Same thing here, "flashing LED sindrome" after configuration. Bought in Croatia in 04/2013, serial number is 3FF902B2804A/242.

Same thing here, a couple of devices bricked after been operating and configured

This is bad!

Antonio

I had such 50 pieces. All were broken.
Sent by the warranty.
All failed when I changed frequencies.
Though one survived.

Surprise from Mikrotik.
But I all the same love Mikrotik, OpenWRT, Vyatta and Unix. But no Cisco.

Well we bought 17 RB751 on the company, and 9 of them were bricked, but we needed all for a project so we look for a solution, apparently when its powered for 6 mins or rebooted after configured (Mesh), something burnout (we dont open it, we smell something burned on the inside) all the leds start to blink, so we have tryied another thing to make react it, we take a PoE adaptor from an SXT and try to powerup with that, the first one didnt work, when we put the 2 powers (Jack and PoE) the RB start to work, really strange, we have a Laptop with PoE,(done by ourselves) the 8 after the first one where fixed with the PoE from the laptop only, strange thing, now we are doing some tests to see how much time they can work, because we think the brick can happen again.

If u are on despair, you can try this solution.

BR
Requium

BTW my last one RB751-2HnD with the more powerful power supply (24v 1,2A) operating perfectly about 1/2 year. No problem since then did not appear. I recommend to purchase stronger power supply automatically with new RB751-2HnD.

But why MikroTik do not do the final quality controll, or changed the pack in power adapter to stronger one - automatically ???

Hi. My routerboard RB751U just died, and I have no one spare RIP. I read, that 24V power supply can take him back to life. But I have none 24V PSU. Was anyone tried it with 18V mikrotik supply?

Thank for reply