what is the ballast rating/wattage? Are you using the right sized bulbs? Have you tried known working bulbs on them? I haven't seen the inside of a magnetic ballast, but if it does have caps, they are a common failure point in most electronics. The good thing is that they are inexpensive and easy to fix. You can google the temp and voltages of the capacitors and find them fairly easily. I prefer to order them online, as running all over town can most often turn out uneventful. You could try radioshack locally, but check their online store first. IIRC they don't carry any caps that require higher temp ratings than 110 Celsius.