Comments on: Hula Defender

Question: Hula Defender

plinth — Wed, 28 Nov 2012 10:25:53 -0800

Help me fix fluorescent light fixture noise in a Williams Defender!

My Defender has massively bad screen hula when the florescent light in the header is on and none when it's disabled (either by pulling the tube or ballast). Picture here.

I noted that the metal panel that it's mounted on was not connected to the cabinet ground strap, so I tried tying it in with alligator clips, but to no avail.

The machine is in fabulous condition with very few sketchy repairs and I'd like to keep it that way - installing a new light fixture is way down on my list of things I'd do to fix it.

Ideas? Would an old/failing ballast cause this? The light seems to come on pretty quickly at power up.

By: kindall

kindall — Wed, 28 Nov 2012 10:35:16 -0800

The ballast is an electromagnetic device and can cause this kind of interference. There might be a piece of shielding missing somewhere.

By: exogenous

exogenous — Wed, 28 Nov 2012 11:08:56 -0800

I've never heard of "screen hula" - so the screen gets wavy or something? You could try asking in /r/cade

By: the Real Dan

the Real Dan — Wed, 28 Nov 2012 11:08:57 -0800

What is that starter doing wedged between the tube and the sheet metal?

I'm talking about that aluminum can with 2 pins coming out of the bottom of it,
one of which I can see in the photo, with a little blue lettering on it.

The pin I can see is unconnected, so that starter isn't doing anything good,
and could be contributing to the trouble you are having. The electric fields around
a fluorescent tube are harsh and weird. Pull that thing out of there, or explain
why you can't.

The ballast is probably grounded to the metal reflector through the power cord, so
don't add superfluous ground connnections with alligator clips.

By: plinth

plinth — Wed, 28 Nov 2012 11:24:52 -0800

I took the ballast out to test running with no light and left it that way until it's diagnosed.