On another forum one Tin Lizzie owner does have several problems with his machine.
Regarding it being the electricity in the house, the easiest way to know if you do indeed have an electric problem is do you blow a lot of lightbulbs? If you turn on a light and it blows out right at that moment, that is usually an indication of a grounding problem because the bulb has gotten a surge causing it to blow. Now if the bulb just goes out while it's on, then the bulb just up and died.
Now, if you really want to shut up the techs at Tin Lizzie, put the machine on a battery back up unit. These can cost between $60 to $150 or more, but a battery back up will take care of any electrical problems coming from the wall.
If you have your machine on a surge protector, plug the machine into the plug nearest the source of power. Do not plug in any other power hungry appliance to the same surge protector or wall outlet, i.e. iron, sewing machine, fan, etc. I have my HQ16 on a surge protector and the only other thing plugged into that protector is a 60 watt lamp and I have nothing else plugged into that wall outlet.
Have you had the electric company check the meter? Over time the meter can actually work loose and cause the house to have a "Low Amp Draw" even tho the electric company will tell you that does not exist. After replacing two freezers, refridgerator, and water heater it was found that my meter was loose on the pole. That is equivilent to being half plugged in. Not a good thing.
You may want to check the outlet for consistent power. Go to Radio Shack and get a cheap ($10) volt meter to check the outlet. Plug in the volt meter, and watch it for a few minutes to see if you get flucuation in power flow. It should read a constant 115, if it don't then you need to get an electrician that knows what they are doing.
Sorry for being so long winded and coming off as a "know it all" but I have a masters in electronics and bachelors in computer science and repair. Also had my own computer company for 15 years, kinda ticks me off when techs try to throw blame when they don't know what the situation is.
Good luck and keep me posted on your progress.