PSU Port Down

I had an issue that started over the weekend and lasted through yesterday.  For some reason the radio started reporting the Main PSU was down.  I could access the radio across the link but not via ethernet through the  power injector.  I basically reset the radio and the network switch to no avail.  Traveled back to my shop and started working to get a new radio ready and the issue cleared up.  Has been clear now for about 12 hrs even through one of the worst thunderstorms we've had in a while.  So has anyone else had an issue like this or have an idea where to start on finding the problem.  Below is a screen shot of the syslog showing what was being reported.

Any ideas or advice appreciated.  This is truly a new one on me.

It could be by wiring or voltage suppressors. You already did tests to rule out the wiring?

hello Sirs,

May i ask if what is the possible cause of main psu port down,i can access both radio , link is up, but the data traffic from the equipment of service provider is not passing through until last mile or at the client,

The alarm tells us that the Main PSU port is not connected to another Ethernet device. That could because of wiring faults, failure of the connected switch or router, the switch or router is powered down, or the cable has been inadvertently disconnected at some point.

Are you able to manage the other end of the Ethernet link?

Since you can manage the ODU across the wireless link, you could use the Cable Diagnostics feature in PTP 650. Please share the results of this test.


I had forgotten all about this thread I started.  So to make a long story short I have had this happen more than once now and what I have found to be the culprit each time is the lightning protection. No indication of any lightning strikes but for some reason they become temperature sensitive. As recently as a month ago I had one that would quit talking when the temp reached around 84 degrees. When it cooled later in the day it would start talking again. On this particular one I could still access the radio via the port but it would not communicate through a switch. Replaced the protection and it's been solid for a month now. 


I am having exact problem “Main PSU port : Down” , I cannot access thru ethernet but the device has a power via POE and can be accessed using wireless.

Is this a device problem or the utp cable only?


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We are having a very similar problem with a new PTP670 system we recently installed. We haven’t actually seen it from a remote end perspective, but the copper port of the PIDU will just randomly go up/down/dark. After a while it will clear itself and everything is good. We do not see any Ethernet errors on the radio and have tested the cable with LPU’s bypassed. We plugged laptop directly into PIDU and it shows cable unplugged and then connected, it does it over and over. We initially that it was a bad port on the switch, but after testing with laptop we ruled that out. This has happened several times over the past few months, one of time with another PTP670 link off this tower. (Both are connected via PTPSYnc units)