Certain appliances--refrigerator, microwave, washer, dryer, air conditioner--no longer work, while light bulbs, computer, and fan still work.

I had an electrician here recently because at one point nothing worked at all. It all started when the microwave (while being used) started wavering a bit, as though it was about to turn off. It then did. [It gave me the impression that it wasn't getting enough power.]

The electrician fixed things (he replaced a box-like thing at street-level; it was called something like a "converter" but that's not exactly right) but then the "bigger" appliances started to not work. By the way It was a neighbor of mine who offered the electrician the solution (the box that needed replacing), since apparently it's been a particular problem of the whole building.

What type of building is this? Also have you tried talking to the power company yet ?

Hi Caveman

Are you on breakers or fuses?

The significant term here is "Building".

If this an apartment building or a Condo you need to stay away from any electrical work. Only licensed electricians may work on electrical issues within a multifamily building.

The list of failing devices is a little overwhelming for an apartment.

To begin with, a dryer is a 240 Vac appliance I don't know about the a/c unit. This is significant because a 240Vac appliance uses two ungrounded (120 Vac) branch-circuits to create the 240Vac.

So suspicion now falls on the "Supply Side" conductors. If one of the hot busbars is failing because of any reason (a meter base that has weak/poor connections - a failing feed conductor) you would lose quite a bit of circuits in several different rooms while other rooms and lights might work just fine.

The immediate thing to do is to have the power company come out and verify that they are supplying the proper voltage and amperage to the building.

If that is correct than the "Landlord" must get a licensed electrician to determine the failure and fix for the problem. I suspect that the failure is between the main feed and the feed to your apartment.

I don't understand why the electrician didn't take a simple volt meter reading at your service panel to make sure your apartment was getting 240 Vac on the feeders.