Mantbox 5 19s failures, anybody else seeing this

Hi all,
Over the last few months I have had to replace the baords in 4 MANTbox 19s units. The AP starts to become unstable and locks up totally every few days or so requireing a total power cycle to revive. have checked and replaced the obvious like PSU etc, Once the board is eplaced all is ok again.

Is anybody else noticing this?

Another one going the same way. am I really the only one who is seeing this?

Guess nobody else is having same issue. I am wondering if it is something to do the the upgrade process. I am going to take down an affected ap and reset the config to factory then reconfig with latest firmware and see if that solves it

No, uptime over the year, ca. 15 item