A problem that we have always noticed with 400 series routerboards is that when there is a quick power brownout they tend to completely lockup. It seems that the only way to fix problem is to power cycle. This problem is typically remedied by putting our 433 AP's on small battery backups. Although, the battery doesn't completely solve the problem. We are a WISP in Oklahoma were thunderstorms are extremely common. All our tower installations have grounding and POE with lightning protection. The problem we are finding is that when the POE surge protections clamp down on over-voltage it simulates a brown-out that typically locks up the routerboard. We don't see this from other vendors (Ubiquiti, Tranzeo, etc); with the exception of cheap Linksys routers, which lock up often. I have few tower that are very prone to near and direct lightning strikes with redundant links. When it happens both radios will lock up and I have to drive 20 miles to reset it. Is there anything that can be done to make these boards more hardened to simple power blips? Firmware? Should I avoid 400's and go with another routerboard?

This problem was brought to light about 1 1/2 to 2 years ago in this forum. A solution was to change a capacitor in the power circuit of the RouterBoard. At that time we did this to about 1000 routerboards that we had in stock. MT changed this capacitor value in their production at that time.

MT has since redesigned the power circuits in newer RB4xx boards and they don't (or shouldn't) exhibit this problem any more.

Tom

Thanks Tom. I'll change them out with newer boards. Is there a particular way to identify if it is an older run with an inadequate capacitor?

Eric

Just connect PSU to RB and make ~1sec. power outage - on...off...on...off many time if RB power hang up that mean this RB have inadequate capacitor. All RB411U and RB433r3 have new power design.