Hi all,

I have a Mikrotik RB751g-2hnd router. It has been working flawlessly for the past 8 years. I suddenly lost connectivity. The router's lights are glowing but it is not doing anything. I have tried entering the router via winbox but the router does not show up.

How do I do a hardware reset of the router?

What else can I try?
I have also written to Mikrotik sales asking about new models because I am not sure what to replace this router with.

Buttons and Jumpers
• RouterOS reset jumper hole (on the bottom of case) – resets RouterOS software to defaults. Must
short circuit the metallic sides of the hole with a screwdriver and boot the device. Hold screwdriver in
place until RouterOS configuration is cleared.
• RouterBOOT reset button (RES, front panel) has two functions:
o Hold this button during boot time until LED light starts flashing, release the button to reset
RouterOS configuration (same result as with RouterOS reset hole)
o Hold this button during boot time longer, until LED turns off, then release it to make the
RouterBOARD look for Netinstall servers.

from: https://i.mt.lv/cdn/rb_files/rb751U-2HnD-ug.pdf
link from : https://mikrotik.com/product/RB751G-2Hn ... -downloads

or even: https://routers-reset.info/253/reset/Mi ... B751G-2HnD

Hi,
I tried a reset using the reset button. I held down the reset button until the light began flashing. Well, no go. I still cannot get to the router. I have tried manually setting the IP address and gateway on my local desktop and have tried connecting to the router. It does not return any response. Ping also fails.

Is there anything else I can do?

Winbox via MAC (winbox Neighbors tab, click on MAC address) .

next level

Netinstall (= full reinstall of all firmware).

Hi,

Many thanks. I did try winbox but nothing shows up in the neighbors tab.

Hi all,

The mystery deepens. I tested the router this morning and it is back online. I have checked its logs and the last thing I see is a reference to an improper shutdown. There does not appear to be anything else in the logs. I did do a reset but that did not work because all my settings are intact.

What happened? I am guessing I pushed the router into net install mode or something else but there is no log entry to confirm this.

Pranav

Resetting a device can be a delicate operation. Sequence of things is important, and steady holding a reset button pushed in, is hard. The button can have a bad contact with the years (oxidation) as it is never used.

"Unplug the router power, hold the reset button located on the back of the router, apply power and wait until the USER LED starts flashing. Release the Reset button and router is reset to the factory settings."

But OK, glad you have your device back up and running. Check the voltage (health) with Winbox if you can. Powersupplies can weaken while aging.

....... I tested the router this morning and it is back online. I have checked its logs and the last thing I see is a reference to an improper shutdown. There does not appear to be anything else in the logs.

What happened? I am guessing I pushed the router into net install mode or something else but there is no log entry to confirm this.

@bpwl provided you with excellent advice. I would like to add that you should use a good UPS for your Router and ISP and switch gear if any.

Hi all,

Many thanks for the reset procedure.
The router is indeed on a UPS which is an APC SUA1000UXI UPS. The UPS does work. I have tested it.
I did check the health of the router and the health command does not give any output except a blank line.
I checked the router board section and the storage is ok as in there are no bad blocks.

I have taken another backup of the router from system backup and that is all that I can do at this stage.

I have taken another backup of the router from system backup and that is all that I can do at this stage.

Make text export of config ... binary backup is only usable (with ceveat) on same model of routers.

Hi @Metog,
<snip Make text export of config ... binary backup is only usable (with ceveat) on same model of routers.
PL] Excellent advice. I did make a text export as you had suggested and was unable to import it. I however manually referenced the file and got things to work.