Powering up 450AP with POE crossover

[tcknudson]

Had POE crossover installed,
had a 450ap that we supposed might have had lightning damage,
as it did not work even after replacing dead (no lights, fans going full blast) netonix switch.
tried to power up at the bench, with new WS-12-250-DC switch, with power protection enabled,
New switch shut down and will not start even later.
??
does using the POE crossover bypass your protection?
as that is the configuration we use on all switches.

[sirhc]

All our POE Smart protection does is look for a cross short between pairs but is not full proof, it simply reduces some potential short risks.

It is unable to detect for instance all wires shorted together because when we had it being too picky it produced false reports and would not work with all radios.

If you suspected the radio was damaged you should have tested it with its POE brick first, then tested it with your crossover cable with a normal POE brick like a UBNT POE brick which has the same POE PIN polarity as our switches. If you were using 48VH you would use an AF 5/24 POE brick. If using 48V a Titanium POE Brick, if using 24V then any normal airMAX POE Brick, if using 24VH then use an AFX POE brick.

I was not there I have no idea what happened.

But the only way you can damage the switch is you have cross shorts between PINs with different polarity. Another thing that can damage the switch is if the radio is damaged in such a way that it draws more than 1A per pair.

Pur polarity PIN out is explained here: viewtopic.php?f=6&t=1178#p8809

[tcknudson]

I almost feel worse about losing the two switches than I do the AP,
I guess I can send them both in.

[sirhc]

I almost feel worse about losing the two switches than I do the AP,
I guess I can send them both in.

Well the nice thing about us is we repair user damage as well.

We are working on a more advanced protection against shorts and such than Polyfuses to better protect the switch in our next series of switches the WS2 line. Polyfuses are not very granular and are temperature reliant so if we want the Polyfuse to allow full power in HOT environments that means they are oversized in milder temperatures. They are primarily there for safety in the event of shorts and do not protect the switch circuits. This is also how the ToughSWITCH works, same Polyfuse protection method. Our new advanced idea is more complex, more expensive, but will protect the switch from shorts.

Polyfuses are passive over current protection they are slow to open and not fast enough to protect the switch Ethernet Transformers. SOmetimes the Transformers fail and only the port is dead but sometimes the Transformer fails in such a way that it pushed current into the SOC and fries it. We do not have the equipment currently in our RMA department to replace the BGS / SOC so that means the board is dead. We are scheduled to acquire this rework station later this year which will allow us to save more boards and lower some RMA repair costs to customers.

Our new method if it pans out is active over current protection and will protect the switch from shorts.