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Malvineous
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[SOLVED] New device - PoE input died on second use?

Wed Jul 14, 2021 6:31 pm

Hi all,

I'm new to Microtik devices and my first one arrived today - CRS309-1G-8S+IN.

I connected a PoE port on a Cisco switch to the Mikrotik's "POE/BOOT" socket, and the switch powered up, made a few odd clicking and beeping noises, and seemed to operate fine.

I unplugged the PoE cable but when I plugged it in the second time, it made a high pitched noise for a second or so and none of the LEDs lit up. Now when I connect to the POE/BOOT socket nothing happens - no noises, none of the LEDs light up, nothing.

If I connect other PoE devices to the same upstream switch port with the same cable they power up just fine, but connecting the Mikrotik switch to any PoE port doesn't do anything. It only powered up via PoE that first time but not since.

If I plug in the AC adapter it will power up and make the same clicking/beeping noises, and it will send BOOTP requests out the POE/BOOT port, but switching off the AC adapter powers off the switch, even though the manual says it's meant to fall back to PoE power. I've left it off and unplugged for 15 minutes but still nothing happens when I plug in a cable with power to the PoE input port.

Have I been unlucky and gotten a dud device? Or do I need to do some configuration on first boot in order to keep PoE available for power input on subsequent boots? Like I say this is my first Mikrotik device so I'm not sure whether I'm doing something wrong or whether the device is a dud.

I hope I'm just doing something wrong because I read pretty good reviews of Mikrotik devices generally before buying this one, but this experience has made me question whether I made the right choice...
Last edited by Malvineous on Thu Jul 22, 2021 1:33 pm, edited 1 time in total.
 
Zacharias
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Re: New device - PoE input died on second use?

Wed Jul 14, 2021 9:19 pm

It can be anything...

If i were you i would try to power the CRS with another POE device and see how it goes...
 
Malvineous
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Re: New device - PoE input died on second use?

Thu Jul 15, 2021 2:47 am

Thanks for the suggestion. I don't have access to another 802.3at/af source at present but I tried with a passive injector connect to the Mikrotik's original AC adapter and that powered up the unit via the PoE port. So it looks like it's the 802.at/af negotiation that's stopped working? The PoE source switch is still powering a bunch of other devices but even unplugging one of those and using it to power the CRS doesn't work, yet connecting that cable back to the original device powers it up again just fine.
 
tangent
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Re: New device - PoE input died on second use?

Thu Jul 15, 2021 3:07 am

What does the "/system health gauges print" command give?

I don't have a CRS309, so I tried the experiment here with a hEX S, and I observed a few interesting things:

1. Plugging PoE in while it was already powered up with the wall wart didn't negotiate power. It wasn't until I pulled the wall power that it did that, and only during the boot resulting from the power loss.

2. Reversing the sequence didn't give an inverse result. Once it was up on both supplies, unplugging the PoE allowed it to fall back to wall power without rebooting first. (I didn't bother plugging PoE back in to see if it'd repeat #1 or if it would now reacquire power from PoE.)

3. The voltage reports from the health gauge command gave expected values: 24.5 V on wall power, 52.9 V on PoE.

This is with a CRS328 doing the power delivery.
 
Malvineous
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Re: New device - PoE input died on second use?

Thu Jul 22, 2021 1:32 pm

Apologies for the delay responding. The vendor got back to me and asked me to return the item, which they tested and confirmed it was faulty. They shipped me a replacement CRS309 which arrived today. So far PoE has been working fine now. I tried the "/system health gauges print" command on the new unit but it only shows the CPU temperature and no other measurements.

Bit of a bad introduction to Mikrotik so here's hoping the replacement unit will be more robust!

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