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Watts indicated with no cable connected

Posted: Wed Aug 12, 2015 4:16 pm
by smartb
Running 1.2.4

Indicating 20.1 watts with 24v POE and no cable connected.

Re: Watts indicated with no cable connected

Posted: Thu Aug 13, 2015 1:20 pm
by Mikea
Can you post a screenshot so we can see the issue?

Re: Watts indicated with no cable connected

Posted: Thu Aug 13, 2015 1:31 pm
by smartb
Code: Select all
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Tried earlier but it want's a url. How do I browse to a local file?

Re: Watts indicated with no cable connected

Posted: Thu Aug 13, 2015 1:42 pm
by lligetfa
Use the "Upload attachment" link under the Preview button.

Did this port always show phantom current or did it happen after you unplugged something? My guess is the ethernet transformer may have gotten damaged by a short or other electrical trauma. Does the port still work at full gig speed?

Re: Watts indicated with no cable connected

Posted: Thu Aug 13, 2015 2:05 pm
by smartb
Screen Shot 2015-08-12 at 2.32.50 PM.jpg
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We always turn off POE before connecting or disconnecting. This unit was RMA a few weeks ago for same reason and the entire switch hosed up when firmware upgrade was recommended by Chris to solve the issue. Put back in service recently and the problem persists. Port 5 is the problem. I don't know if full gig e works. I would need to try that with a gigabit device. RM5s are the only thing connected and a local PC with 10/100 NIC.

Re: Watts indicated with no cable connected

Posted: Thu Aug 13, 2015 2:26 pm
by sirhc
More than likely your board was damaged by an electrical surge or a "ground potential difference" brought on by a sudden rainfall event.

I give you permission to open this chassis and inspect the board without voiding your warranty.

However if the board is damaged as shown below that unfortunately is not covered by the warranty but we can fix it for you!

Please take a picture of the bottom of the board (you will need to remove the board from the chassis if you feel comfortable doing this).
MAKE SURE THAT SWITCH IS UNPLUGGED FROM THE AC SOCKET AND ALL ETHERNET CABLES ARE UNPLUGGED.

Also report the board S/N and MAC address in your post along with the picture of the board (Top and Bottom).

You will probably see damage similar to the boards shown below.

Both the boards shown below worked fine except that they reported incorrect current on the damaged ports.

The damage occurred during a storm event.

The "AWESOME" thing here is the 2 switches below continued to operate as normal except that the current readings were wrong.

I contribute the continued operation of the 2 switches shown below to the 1500V isolation between DC negative and AC Earth Ground that we put into the design.

THIS IS A REALLY GOOD READ, RECENTLY UPDATED WITH MORE INFO: viewtopic.php?f=30&t=188

CLICK IMAGE TO VIEW FULL SIZE
Damage.jpg
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Re: Watts indicated with no cable connected

Posted: Thu Aug 13, 2015 3:45 pm
by Dave
ie...the boards were designed to be able to survive a large instantaneous shift in a ground potential, but if the shift in potential is high enough, the current/power sensors might go bad, but the network should still function....hard to make everything 100% fault tolerant, but we try...

Re: Watts indicated with no cable connected

Posted: Thu Aug 13, 2015 4:47 pm
by smartb
Will need to take it out of service to do this. Will post as soon as we can. thanks

Re: Watts indicated with no cable connected

Posted: Sat Aug 15, 2015 4:08 pm
by smartb
I don't see anything obvious. In addition to the inaccurate power sense, port 1 and 6 cannot be used to power a RM5 for more than 24 hrs. or traffic stops. I have to power with UBNT POE and if plugged into any port works fine. I had to resize the photos to get by the 2mb picture limit on the forum. SN mac is attached also.

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Re: Watts indicated with no cable connected

Posted: Sat Aug 15, 2015 4:13 pm
by smartb
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