Re: Do not understand
Posted: Sat Mar 11, 2017 2:12 pm
Well we are always sorry when something slips past us like the 3.3V CAPs. We do fully test each switch before we serialize them but in this case they would pass our testing procedure. We did test all Ethernet ports but we did not test all ports active at once. We have since changed our testing procedures to catch something like this in the future.
With the C51 CAP on the 250 watt power supplies it only showed if using less than 40-60 watts and the switch had to be running anywhere from a couple hours to as many as 12 hours before it exhibited the issue. We have since had the manufacturer change their testing procedure of the power supplies plus they changed their BOM (spec a better CAP). We also now do random spot 24 hour burn in tests to help catch something like this in the future.
The Ground MOD is not a defect just something we learned over time examining RMA units that would greatly reduce damage to units from poor grounding. Mind you with this MOD the Ground Current is still traversing the Ethernet Cable as you can not stop this no matter what we did because some radio manufacturers are bonding DC negative to Earth Ground instead of using isolated circuits. Ground current traversing the Ethernet cable is a bad thing that can cause other issues like Ethernet errors. This is why people should do better grounding, we are making the switch handle the current much better but now this current is still traversing the radio to get to the tower so will it handle this ground current????
To test if a radio is bonding DC negative to Earth Ground use an Ohm meter and measure Ohms between a DC negative PIN such as PIN 7 and 8 of the radio and the outside of the antenna connector (SMA or N-Type). If you see near 0 Ohms then it is bonding DC negative to Earth ground and ground current will flow across your Ethernet cable if the electrical service ground rods are not bonded properly to the tower ground rods.
If the unit is an all in one then test Ohms between PINs 7 and 8 and their mounting bracket if it is metal.
Radio like a NanoStation is all in a plastic casing so it is isolated and not a problem.
Now the ground MOD will also help you against Static or ESD charges at the radio/Antenna is you are not running a dedicated ground wire / path as that charge will follow the Ethernet cable down to ground. Static charges build up from wind blowing across the tower/radio/antenna and the humidity level is just eight which often occurs in the Spring as sudden rain event s often follow a sudden temperature change which cycles through the humidity levels just before it rains.
You can RMA the WS-8-150-AC units and we will fix them, sorry.
We could also put up a how to for those that would rather just replace the CAPs themselves? It's not any harder to do then the Ground Current MOD.
We try to be honest about everything and we also try to explain what the issues is which is not the normal way manufacturers handle things like this. The industry standard is to simply deny everything under most circumstances and not many provide details on how to make the fix yourself if you want.
If you want to enact the Ground MOD then simply program one up as a replacement then swap it out. Once you get that unit back to your office you can apply the ground modification and use it to swap out the next unit and so on. This is what we are doing at my WISP. Currently our goal is to have them all swapped out before the rainy season starts when rain is the enemy as it messes with ground rod potentials. Currently we are about half way through the swap out. We are doing the swap out after 10-11PM and total down time per tower is about 5 minutes. You can also use this maintenance window to test and swap out any batteries.
With the C51 CAP on the 250 watt power supplies it only showed if using less than 40-60 watts and the switch had to be running anywhere from a couple hours to as many as 12 hours before it exhibited the issue. We have since had the manufacturer change their testing procedure of the power supplies plus they changed their BOM (spec a better CAP). We also now do random spot 24 hour burn in tests to help catch something like this in the future.
The Ground MOD is not a defect just something we learned over time examining RMA units that would greatly reduce damage to units from poor grounding. Mind you with this MOD the Ground Current is still traversing the Ethernet Cable as you can not stop this no matter what we did because some radio manufacturers are bonding DC negative to Earth Ground instead of using isolated circuits. Ground current traversing the Ethernet cable is a bad thing that can cause other issues like Ethernet errors. This is why people should do better grounding, we are making the switch handle the current much better but now this current is still traversing the radio to get to the tower so will it handle this ground current????
To test if a radio is bonding DC negative to Earth Ground use an Ohm meter and measure Ohms between a DC negative PIN such as PIN 7 and 8 of the radio and the outside of the antenna connector (SMA or N-Type). If you see near 0 Ohms then it is bonding DC negative to Earth ground and ground current will flow across your Ethernet cable if the electrical service ground rods are not bonded properly to the tower ground rods.
If the unit is an all in one then test Ohms between PINs 7 and 8 and their mounting bracket if it is metal.
Radio like a NanoStation is all in a plastic casing so it is isolated and not a problem.
Now the ground MOD will also help you against Static or ESD charges at the radio/Antenna is you are not running a dedicated ground wire / path as that charge will follow the Ethernet cable down to ground. Static charges build up from wind blowing across the tower/radio/antenna and the humidity level is just eight which often occurs in the Spring as sudden rain event s often follow a sudden temperature change which cycles through the humidity levels just before it rains.
You can RMA the WS-8-150-AC units and we will fix them, sorry.
We could also put up a how to for those that would rather just replace the CAPs themselves? It's not any harder to do then the Ground Current MOD.
We try to be honest about everything and we also try to explain what the issues is which is not the normal way manufacturers handle things like this. The industry standard is to simply deny everything under most circumstances and not many provide details on how to make the fix yourself if you want.
If you want to enact the Ground MOD then simply program one up as a replacement then swap it out. Once you get that unit back to your office you can apply the ground modification and use it to swap out the next unit and so on. This is what we are doing at my WISP. Currently our goal is to have them all swapped out before the rainy season starts when rain is the enemy as it messes with ground rod potentials. Currently we are about half way through the swap out. We are doing the swap out after 10-11PM and total down time per tower is about 5 minutes. You can also use this maintenance window to test and swap out any batteries.