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I have a new dc 12 port 250w switch that we installed less than a week ago, then Saturday morning the site was offline. i went to the site and noticed the switch was rebooting over and over again. rebooting so fast I couldn't even get consoled into it. i ended up swapping it out for a different switch to get us running again.

powered by 54v DC
tower and swtich are grounded - fed by fiber from he router.

of course, the switch seems to be working fine here in the lab.
Any suggestions?

I have no idea but I would upgrade it to v1.4.2 though as the sheet of paper that was laying on top of it suggested when you un-boxed it.

I am not sure this is caused by RF noise or what the issue is at this time?

I would first do a standard bench test by testing all ports to achieve 1G connection to say your laptop with no POE turned on.

Then I would use something like a NanoStation and power it on each port with 24V POE and verify the current sensors for each port are not damaged as they will register 2-4 watts on the status tab.

After that we can probably safely "assume" the unit is probably not damaged in anyway.

You say powered by 54V DC but you lack what that source is exactly, how many watts/amps, what gauge wire and so on.

You say tower and switch are grounded but this is a vague description.

Does this site have AC grid power and if so explain where it comes from.

What is the tower and what type of grounding does it have?

If there is grid AC power is its Earth Ground rods bonded to the tower grounding rods.

Do you have a ground wire that is bonded to tower grounds and service grounds running up the tower and then to each radio/antenna, meaning a dedicated ground path other than the Ethernet cables that is shorter and less resistant?

Are you using ESD drain wire Ethernet Cable and do you have a decent service loop to insure its path is longer than intended ground path?

So far there has been 1 person report that the new Rev F fixed is RF issue at FM site:
viewtopic.php?f=17&t=1342&start=70#p13804

Problem is most people always report a problem but seldom take the time to say "hey, things are working fine"

This makes it hard to gauge things.

THe first thing I would have done when I arrived was put a volt ohm meter on the power source and watched what it was as the unit was rebooting.

My guess is the unit booted up and started drawing power and knocked the voltage down and it rebooted?

firmware was upgraded to the newest at the time it was opened - maybe two weeks ago at most. 1.4.1. I want to say i have one other rev F this is working good at a building about a block away. this original switch was working good for a week or so, then all of a sudden its started rebooting. we shall see with this 2nd one that i installed Saturday. This suspect switch is working good in the lab today. all ports are working and no reboots.

this is a building roof top - 550' tall. Everything is professionally grounded, i cant tell you how the tower or AC is ground, but im sure its fine. The tower mask, my equipment box and switch are grounded to it too.

power is clean house power. 120v AC. We are Using a meanwell Ad-155C dc power supply to charge our battery bank. its output is 56v DC & 4x 150ah batteries for a UPS. DC power is clean coming off the battery bank. tested 56v at the batter/charger side and at the switch terminals. voltage was not dropping at the switch. swapping the switch for a different one fixed this issue so far.

Thx
Scott

I started seeing the same behavior with switch 2 today at this same site. I completely shut down the tower power. Turned down the DC voltage from 56v to 51v and powered it back up. everything is stable now for the last 3 hours. I also updated firmware to 1.4.2 just now.

slepere1 wrote:I started seeing the same behavior with switch 2 today at this same site. I completely shut down the tower power. Turned down the DC voltage from 56v to 51v and powered it back up. everything is stable now for the last 3 hours. I also updated firmware to 1.4.2 just now.

So I am confused, why do you use a DC switch if you're powering it from an AC power source generating DC power?

Are there batteries in the mix at all?

If you're powering it from an AC power source making DC power what type of SINE wave is it, modified or pure SINE wave?

What is the model of your DC power supply and where is it located?

we are using a Mean Well AD-155C AC-DC Enclosed power supply with UPS function; Output 54Vdc at 2.7A +53.5Vdc at 0.5A
https://www.meanwell-web.com/en/product ... ct/AD-155C

our rack and routers are indoors about 200' away from the rooftop tower. use srun Dc using 12g wire and 12 strand fiber outdoors to the tower where the switch is located in a top site box, this keeps the Ethernet runs short to the radios.

yes there is 150ah batteries.

slepere1 wrote:we are using a Mean Well AD-155C AC-DC Enclosed power supply with UPS function; Output 54Vdc at 2.7A +53.5Vdc at 0.5A
https://www.meanwell-web.com/en/product ... ct/AD-155C

our rack and routers are indoors about 200' away from the rooftop tower. use srun Dc using 12g wire and 12 strand fiber outdoors to the tower where the switch is located in a top site box, this keeps the Ethernet runs short to the radios.

yes there is 150ah batteries.

Looking at this power supply sheet is this what happens?

Meanwell supplies power to switch but also has an input terminal to hook to batteries for backup and the Meanwell keeps the batteries charged.

If AC power drops then the Meanwell draws power from the batteries.

I am not sure why you would use the WS-12-250-DC unit here, you should use the WS-12-DC as you are supplying "conditioned" power to the switch.

The whole idea of the WS-12-250-DC unit is that it expects to be hooked directly to the batteries and deal with a wide range of voltages from 9V to 62 or 72V depending on Rev as the battery bank discharges.

When the switch is hooked to the batteries direct it is getting a nice clean SINE wave of power whereas the meanwell is delivering a modified SINE wave and could also inject noise on the DC line that the batteries would normally filter/absorb.

Also note that this Meanwell is not capable of delivering the required amperage the switch needs (could deliver) as it is only has 2.7A which is a bad idea.

You're not using this model in the application it was designed for, can you hook the switch to the directly to the batteries and just use the meanwell as a charger or get another charger unit not a power supply?
Or swap the WS-12-250-DC with a WS-12-DC which is designed for this type of application.

sirhc wrote:When the switch is hooked to the batteries direct it is getting a nice clean SINE wave of power...

I'm confused by that statement. Should not one get DC when hooking to the batteries? One should not see a sine wave, much less even a ripple from any good DC source.

lligetfa wrote:

sirhc wrote:When the switch is hooked to the batteries direct it is getting a nice clean SINE wave of power...

I'm confused by that statement. Should not one get DC when hooking to the batteries? One should not see a sine wave, much less even a ripple from any good DC source.

Yea, my bad, it has been a long day!

But he is powering the WS-12-250-DC unit from a Meanwell power supply that gets power from AC and falls back to batteries when AC drops which confuses me as the switch to use in this application would be the WS-12-DC not the WS-12-250-DC which is meant to hook to the batteries directly and accept a wide range of voltages and condition or adjust the voltage for you.

His problem could be the Meanwell power supply it's hard to tell fault. I mean if the Meanwell voltage blips the switch will reboot but if hooked to the batteries this is less likely and he can monitor the voltage input from the batteries and see it getting low whereas if the Meanwell cuts out for what ever reason even for a second the switch will reboot.

I suggest using the WS-12-DC for this application or hook the WS-12-250-DC to the batteries direct and use just a simple charger.

I do not think this problem is related to RF noise as a couple people now have reported that the new Rev F units fixed their issue at FM tower sites but when we asked if they were using the WS-12-250-DC or the WS-8-150-DC they did not yet respond so who knows.

We have shipped several hundred WS-12-250-DC Rev F now so you would think if this was a design flaw many people would be reporting it?

These are the days that I wish we had a weather net and transporters so I could just pop in and work with people to track down the problem.