No Sync from CMM

I’m having an interesting situation at one of our sites. Here’s the specs of the site:

3 - 2.4 Ghz APs P9 on 8.1.4
1 - 5.7 Ghz BH P9 on 7.2.9
1 - CMM Micro

I have the backhaul on 7.29 because the other end is a P8 running 7.2.9.

Anyways, the three access points can get sync fine from the CMM, but the BH shows “Error no sync.” I’ve tried different ports on the CMM as well.

What would cause this?

Had this happen with a bad cable.

You can switch places of the master and slave if the new cable fails. In the mean time you can put sync cable from the RJ11 port of the CMM into the appropriate port of the BH and set it to receive sync from timing port.

Make sute the GPS antena is aligned correctly.

amarriott wrote:
Make sute the GPS antena is aligned correctly.

The GPS is seeing 8 satellites and sync is working on the three APs connected to the CMM.
Jerry Richardson wrote:
Had this happen with a bad cable.

I thought about a bad cable but it seemed odd because the BH gets power and ethernet, just not sync. I'll try a cable and see what happens.

Same thing happened recently to me with one of our 5.7 BH. One night we lost the connection to a remote 900 AP due to no sync being generated at the head end. Found the Error-No sync issue and thought it was a bad crimp, replaced both RJ45 connectors with no avail. Ran a new tested line up the tower, still no sync. I stole another 5.7 AP from the same spot on the tower (that happened to be linking to an unused site at the time) and it connected up fine. That proved the cable was good, the CMM ports were good and the 5.7 AP module was no good. Back to Motorola it went and we ordered a new one.

We always check the connectors on the board before we RMA the modules which seems to boot up but don’t have Ethernet connection, which can’t get the default plug to work or don’t receive or pass the sync. From our experience more than half of the problems are fixed with soldering the pins from the RJ45 directly on the board.

I agree erkan, I have seen every connection from the RJ45 connector on a 900 SM be lifted off the board due to poor solder joints. The RJ45 port on the 5.7 AP we had go bad looked fine under the scope so we returned it.