Self-start circular fluorescent lamps

I have a 32 watt fluorescent lamp in a fixture. Lately, its starting has been balky. At first, I thought that the wall was faulty. I found out that by taping the lamp or power socket, I could get it to start. I recently found out that gently touching the lamp envelope near its electrodes also helped start the lamp. Now I have many speculations as to just what is happening. At this point I am falling back upon believing that my hand capacitance or electrode vibration just pushes the lamp to electrical breakdown.

I sure would appreciate hearing from anyone who has actual knowledge of what is going on.

The only way to have actual knowledge of what is going on is to examine your setup. But your assumptions are on the "reasonable" list.

Sometimes as tubes get older they emit less electrons from the cathode for a variety of reasons. Less electrons having a chance to hit a gas atom. You could be providing a capacitive coupled path giving a greater chance for electron-gas collision, or the socket could be making poor contact.

Tom

Does your fixture have an automatic starter? Like this:

That could be going bad. Try replacing it. The lamp itself could be bad (open heater) and the start circuit would never operate. Check the continuity between the two pins at each end of the lamp.

By holding your finger near the lamp, you could be providing enough capacitive coupling to allow it to initiate an arc with line voltage as you suspected.

My best guess at this time assumes that these circular lamp have fillament electrodes as if they did use glow starters. One of the filaments is broken and the tube would not work with glow starters even if they were used. I think the initial high voltage can break down the mercury vapor between an intact filament and a broken one.

When I get a new lamp, I can check it out filament continuity. Starting seems to depend highly upon the lamp's orientation in gravitation.

[snip]

What's the lamp part number?