Mecer modem/router behaving strange.

[blue-eye-boy]

Hi, so many know I'm a noob with this. My whole setup with raspppoe, routesentry is good. But I noticed that sometimes my router/modem just stops. The lights flash, then goes off, the flashes again and so on. I can switch it off and on, anything, it just keep doing it's thing. then all of the sudden, all is good again. Can this maybe be a setting of some kind, the modem "refreshing" or what?
ps: I know this may be funny, but our electricity is not that good. The voltage sometimes drops to +- 170volts. Never higher than 220v, but many times lower. Now tonight were one of those times. Can this maybe be a problem?