My liftmaster did this repeatedly, driving me nuts, even after pulling out on that center contact tab at the bottom of the light bulb socket. It'd work for a while and then revert to flickering. If the bulb was overtightened it wouldn't light; if it was undertightened it would light but soon revert to flickering. I could never find the sweet spot to keep it lit for more than a month or so before it would start flickering again, and eventually just go out completely. The garage door installer told me to wind some teflon plumber tape around the bulb threads and that would solve it. Well, that helped keep the bulb in place for maybe a few weeks longer before it failed again. Finally I pulled the power cord (again, for what seemed like the fiftieth time) and stuck a small, perhaps 1/4", length of synthetic rubber pencil eraser behind the center contact tab, in the bottom of the socket. That way when I tighten the light bulb it slightly compresses the eraser, forcing the contact tab against the bottom of the bulb and ensuring a tight fit. The snugness also prevents the bulb from vibrating loose (you can also wind a bit of teflon plumbers tape around part of the bulb base threads to help tighten it up, as suggested to me by the garage door installer). This solution has worked now for well over a year. Not bad since I messed with tightening and retaping the bulb repeatedly for well over a year prior to the fix. I'm not sure that UL would approve of my methods...

This exact same thing is happening at my house, as i type! I am in the living room, this room's wiring is not affected but the kitchen is flickering and going off and on like crazy...wind is blowing outside and hubby has discovered it has something to do with electrical pole across the road. we called electric company and they came out and checked where the wiring is attached to the house, no flickering there...but when hubby goes out and shakes their pole...all hell breaks loose! When they came to check the pole, the guy didn't even go up there, and told my husband to stop shaking the pole...yet nothing has been done to fix this...guess he will be calling them today and stirring up a stink...i believe this on / off crap could damage our appliances and such. Funny, nothing flickered last night during storm with 50 plus mph winds...go figure....

If your lights are dimming and then returning to normal brightness, and you never see them brighten then get normal again, you probably don't have a loose neutral and the associated risk to appliances. But you may have a problem - or not. Momentary drops in voltage may be caused by very large transient loads in your house or a close neighbor's. Whether you should be concerned depends on how wide the swings are and how frequent. A good electrician should be able to help you determine how serious your situation is. As for your computer UPS, many of them self-test from time to time. I think mine does it weekly, but I'm not sure (I'd have to look at the manual). The behavior is as you describe - the inverter kicks on and it hums and maybe beeps for a few seconds. Probably nothing to worry about.

It appears that the power company just came out and replaced the line going to our house from the pole. They did not ask us and while doing this drilled a couple new holes through our siding, so we are very upset. When i called I asked them to check the pole because we think we have power quality issues. So, our problem is not any better than the other day and now we have more holes in the house. They did not seem to monitor the power going into the house. I did check and we do not seem to have a transformer near us. It is a couple houses down from ours and our electric pole appears to be the last one. They then start on the other side of the road two houses down. Maybe the wire goes under the the ground to the other side of the road? Anyways, I am very upset about this. I just want to find out if it is OUR problem or theres! Is that so hard? Our house was built in 1850 and we do have updated electric, but maybe there is something funny going on and it needs to be fixed. The electric company didn't seem to concerned when I called them but I wasn't able to talk to a technician.