In the kids bathroom upstairs the light fixture was 2 4' florescent tubes fixtures for a total of 4 tubes. When we moved in only 1 of the 2 fixtures was working. I chalked it up to dead bulbs and put it at the bottom of my mental to do list. A year later when I happened to be buying new tubes for somewhere else I picked up a couple of new ones for the bathroom too, but even after installing new bulbs the fixture failed to light. Put a new ballast on the list for it then. In the next year or 2 that passed I thought of it only rarely, wondering if a bad ballast wasted a lot of electricity or put a lot of noise onto the powerlines or anything like that which might cause me trouble.
Some time later my mother in law asked me to replace a fixture for her in her kitchen which also refused to light up a new bulb. It was one in a series of tubes that run around the soffits in the kitchen and so was on with the rest of them even though it did not light. When I turned that power off and removed the old ballast it was HOT. Too hot to touch without being burned, it has started to blacken the metal case of the lamp housing it was so hot. I don't know how dangerous this really is, but I felt it was probably a good thing to have replaced it with a nice new, cool running electronic ballast for her. This got me thinking again about the lamps in the kids bathroom and that I should probably replace those ballasts too...
The light switch in the kids bathroom is wired into the Home Automation System. The motion sensor in there creates an event in XTension to turn the lights off in 10 minutes after there is no more motion. The kids just can't seem to remember to turn certain lights off so I've automated it. This stopped working recently and in my mind I knew it was the faulty ballast interfering with the X10 signal to the switch. So that moved it up to the top of the list of stuff to fix.
Yesterday I finally got around to replacing it. The fixture was 2 just bare 2 tube fixtures up in a soffit. The simple metal rectangle that houses the ballast with the tube plugs sticking down at the ends, nothing fancy and very easy to open up and replace the ballast. You just squeeze the sides and the top (or is it the bottom?) of the case will pop off exposing the wiring. Cut out the old ballast and wire in a new one.
Following the tradition of upgrading everything as I fix it around here I did not just replace with 2 more cheap magnetic T12 tube ballasts, but instead upgraded it to a single 4 T8 tube electronic ballast. Since there were 4 tubes in there and the fixtures were only about 3" from each other I just punched out some of the wiring holes that were next to each other, filled in with rubber grommets to keep the sharp metal from cutting the wire insulation over time and ran the wires for the second set of 2 bulbs into the other fixture. Should reduce ballast losses by having only one in what is basically a 4 lamp fixture anyway. T8 tubes are the skinny ones, T12 bulbs are the larger diameter bulbs that you remember from the distant past. T8 tubes generally output the same or more light with less power. A 40 watt T12 tube can be replaced with a 32 watt T8 tube and you'll still get more light. It's not a big difference, but every little bit adds up. Plus you don't have to make any changes to the fixture as the pin spacing on a T8 is the same as the older T12 bulbs. They will fit right into the same sockets. But you do have to get a ballast that is designed for the T8 bulbs. You can't just change out the bulbs without changing out the ballast too.
The old ballasts were interesting, they had already been replaced once as evidenced by the wire nuts in the circuit. The native ballast that comes with the lamp will be wired directly to the tube sockets but once you replace it you'll have to snip those and wire nut in the new ballast. So this was actually the second set of magnetic ballasts to fail in their and this is not that old a house... The one that wasn't working anymore did show signs of having been overheating. The potting compound that they fill them with, whatever it was, was actually leaking out of the corners of the ballast housing.
And while I was in there I actually connected the ground wires that were just floating in the case not screwed down to anything. Another lovely piece of electrical work that and may have contributed to the failure of the ballasts. They all suggest that the case of the lamp must be grounded, not just for safety but for proper operation of the lamps as well.
I don't know if this was a fire hazard or just an annoyance to have only 1 set of dim, flickery tubes in there, but they are all better now and I'm happy with the result. At least the result of the lamps, unfortunately it did not fix the problem with the light switch not being controllable.
It's a switchlink brand non-dimmable florescent capable device, but honestly I've never had good luck with that brand. I decided it must have just lost it's X10 address and needed to be reprogrammed, but after going through that dance half a dozen times it just refuses to respond to anything at all. Scratch one more switchlink device from the rolls of house duty. In the next few days I'll be replacing it with a UPB switch set to non-dimmable. I still have a few UPB commands that i need to build into the system before it's ready to roll out, but it wont be long before I can install these things and move the UPB interface from the test bed here into the house proper.