WS-12-250-DC Dropping POE voltage

[mike@surfglobal.net]

As we are upgrading sites to Ubiquiti AC Prism Gen2 radios we see conditions where both this DC model and AC Model will drop the POE voltage in mass causing all the connected AP's to reboot at the same time and nothing in the log file. The only fix we have found is to power the radios via Ubiquiti POE. . Running the latest firmware 1.4.8. Any thoughts?

[Julian]

latest firmware is 1.4.9, available on these forums, not sure that that will change anything re: this issue.

Can you elaborate on the conditions you're seeing and the configuration you're trying to make happen?

Thanks!

[lligetfa]

How do you know the PoE voltage is dropping? Are you trending it with SNMP or seeing event log entries?

[mike@surfglobal.net]

1.4.9 wasn't out when we were experiencing the issues a week ago. We know the voltage has to be dropping because 4-6 AP on a switch will all reboot in unison so it has to be the voltage. To me it looks like the AC Prism Gen2 radio draw possibly enough extra current so when you start loading a switch up with them it triggers some sort of overload condition in the switch. The switch is never close to its max power draw and its not dropping based on the power priority so its not a controlled shedding of devices. Its triggering some sort of bug or design flaw.

[lligetfa]

We know the voltage has to be dropping because 4-6 AP on a switch will all reboot in unison so it has to be the voltage...

In the absence of empirical data, it could be circumstance. Could they also be seeing the same broadcast packets and be the cause for reboot? How frequent and repeatable is this? Could you take one or two of the radios and power them via PoE brick to see if they still go down?

[lligetfa]

Also, could there be a ground potential shift that is triggering the remote reset circuit?

[mike@surfglobal.net]

They work fine off the Ubiquiti POE's.

[sirhc]

Please upgrade to v1.4.9 as there is an IMPORTANT FIX for the new UBNT Discovery protocol which can cause issues.

More information is needed to help.

Please post up the following TABs:
Status
Ports
Power
Device/Status

What is powering the WS-12-250-DC?

Is there and electrical service at this site and if so are the service ground rods bonded to the tower ground RODs?

[kdsnetworks]

I have the similar experience with this units, however, I will provide a bit more info.

WS-12-250-DCis running on a 24V DC system running latest FW 1.5.0 It was working great for the last 3 years with rockets M5. We have 1 AF5x at 48VH and rest is on 24V.
After an upgrade, to rocket prism and prism station AP things started to act up. The only device that was holding up was the af5x and the switch itself ... All other devices powered by 24v would reboot on a random- all at the same time - So thinking it could be 24v bus issue we reduced the number of devices powered by 24v to 8 (from 11) and all is stable now.

So based on the above we think there could be a few possibilities.
- the 24v bus cannot handle the higher power draw from the prisms. (when all powered max we saw was 120-135 Watt)
- the 24v bus while on a higher load lowers to its voltage to like 16v causing all prisms to reboot.
- the 24v bus while on a higher load reset itself causing quick power interruption and reboots all
- the 24v bus is defected and should be replaced. (we have the same issue on several sites )

There must be a reason why while 11 are powered at 24v things are acting up and when reduced to 8 all is great and stable.

If someone could elaborate on the above that would be great.

Thanks
Robert

[sirhc]

I have the similar experience with this units, however, I will provide a bit more info.

WS-12-250-DCis running on a 24V DC system running latest FW 1.5.0 It was working great for the last 3 years with rockets M5. We have 1 AF5x at 48VH and rest is on 24V.
After an upgrade, to rocket prism and prism station AP things started to act up. The only device that was holding up was the af5x and the switch itself ... All other devices powered by 24v would reboot on a random- all at the same time - So thinking it could be 24v bus issue we reduced the number of devices powered by 24v to 8 (from 11) and all is stable now.

So based on the above we think there could be a few possibilities.
- the 24v bus cannot handle the higher power draw from the prisms. (when all powered max we saw was 120-135 Watt)
- the 24v bus while on a higher load lowers to its voltage to like 16v causing all prisms to reboot.
- the 24v bus while on a higher load reset itself causing quick power interruption and reboots all
- the 24v bus is defected and should be replaced. (we have the same issue on several sites )

There must be a reason why while 11 are powered at 24v things are acting up and when reduced to 8 all is great and stable.

If someone could elaborate on the above that would be great.

Thanks
Robert

About 18 months ago we dramatically increased the 24V power supplies on the WS-12 and WS-26 boards (almost 50% increase) increase.

Since this unit is 3 years old it is possible the 24V power supply is simply failing under the load.

You can RMA it and we can modify the power supply to match the current production 24V power supplies for about $50

Make sure you specify the 24V power supply on the board in not handling a full load of 24Vn devices as the Symptoms when requesting an RMA.