I had this item shipped to work, I picked it up today and tested it briefly at work. Item worked fine I then brought it home and when I plugged it in all 5 Ethernet interface lights (but not the wireless interface light), the power light and possibly the ACT light were blinking in Unison. I attempted to use the reset button as indicated in the quick setup guide to initiate a configuration reset, then I attempted to do a netinstall, both did not work. Plugging it into another device either ethernet card on a laptop or network switch on a laptop result in the other device not detecting the routerboard and no change in the lights blinking.
Is my routerboard bricked already? I emailed the supplier I purchased it from already but It’s already pretty late in the day so I’ll wait till tomorrow to try calling them. But I was hoping someone here might have seen this in another routerboard and have some idea what happened.
Well, that was fast. Probably, you’re the first with a bricked RB751.
Did you actually modified something in the config, while you tested it at work, or just plugged in, logged in, logged out, pulled out the power supply? Maybe the RB751 was saving something into the flash, while you unplugged it.
I also had one of my first pair of RB751U-2HnD die within the first 3 hours of receiving it on Wednesday.
Did a full config, was running fine for about 2 hours, then everything dropped. All the lights on the device were blinking in unison, about 3-4 blinks per second. No amount of adding or removing power, waiting for the device to discharge/cooldown, or use of the reset/netinstall mechanisms got any response.
On the plus side, its partner has been running without incident for almost 48 hours now. My RMA unit is on its way from my reseller, so hopefully, it’s just a normal incident of a bad unit. Time will tell.
Connect ethernet port 2, 3, 4, or 5 to an 802.3af POE switch. Then connect an 802.3af POE device like a VoIP phone to one of other ethernet ports 2, 3, 4 or 5 on the same RB751U. You’ll notice that the POE device will start into a loop of power cycling. I did this test with a Dell 3548P and a Polycom IP331 phone. This doesn’t occur with an RB750GL.
This might or might not have anything to do with the other power issues on the device, but there is clearly some oddities here. I don’t think power should be leaking between ethernet ports.
Please contact the seller for RMA repair/replacement if you run into any issues, just like with any other device. Changing the PSU is not recommended, as it doesn’t completely solve the issue, the unit still needs repair.
The new AC adapter arrived on Friday, but I didn’t get a chance to test it until today. The good news is everything is working again!
Thanks again to Tom at http://roc-noc.com for addressing the problem so quickly!
I came here to share my results and saw this post from normis:
So now I am confused about what to do with my device. I am also curious if the device comes with a warranty. I could not seem to find this information at the http://routerboard.com/ site.
I was hoping to get some feedback from others who have experienced the same problem and fixed it by using a different AC adapter. Are you planning to keep the device or request an RMA? Also what AC adapter are you using day-to-day, the supplied one or a different one?
I feel bad now asking Tom for an RMA after he went through the trouble of sending out a new AC adapter which fixed the problem. But I also don’t want to have a problem 6 months down the road and not be able to get a replacement.
Hey Normis, are you able to confirm if the problem means there is something wrong with those boards or can it simply be resolved for good by using a higher voltage power supply?
Yes could you expand upon what not completely resolving the problem means?
After getting mine functional again it has been running fine on the factory adapter since.
It’s had lots of configuration time and reboots since then as well and no more blinking lights
yet.
The high power adapter will not solve the issue. We are working on making a procedure for this case, please contact the seller for more details. They will be informed in the next few days.
So, you already know the root of the problem? Can this be repaired at home with the necessary tools?
I’ve just received my RB751, after a lot of waiting, and I don’t really want to spend time with waiting another one month for a spare unit. Also, this information will be handy, if we face this failure after warranty.
Do you know the root cause of the problem? You did not answered this.
What if I will send back my bricked 751, and after ~ 1 month, I will get an another one with the same defect?
We cover the warranty for 1 year as do most other distributors, so yes you would get a replacement. No, it should not have the same defect.
Mikrotik is working on a way for distributors to easily identify the bad units. We are still waiting for this information. Yes they have identified the cause of the problem.
This is a new product and there is always risk of bugs or defects with new products. Please be patient with them.
