"T i m" wrote in message
...
On Wed, 14 Apr 2021 16:38:06 +0100, "Brian Gaff \(Sofa\)"
wrote:

no cannot say I have heard of it as normally they use switch mode psus and
nothing else vibrates.Really you need a magnetic component at 50hz for
that noise.

And that's the thing, this really is (was) a real 50Hz mechanical hum.

With regard to the broken pins, I'd be tempted to araldite them
in where they should be to stop the light working free and falling on
somebody or inside the diffuser.

I've pulled them out now as the fittings seem to be dead anyway but I
do intend opening the end up a bit and see what I see. If there is
nothing that looks repairable I may try taking it to bits and seeing
if I can get the LED's out.

Try a gentle squeeze of the plastic ends, probably wearing gloves to see
if
the noise changes in character.

I've done that with the entire fitting and it does seem to make a
difference so something is causing the metalwork to resonate.

Could there be an earth not making very good
contact between the fitting and a large bit of metal.

The main earth seems sound FWIW.

seems the I've noticed
electrostatic hums, though they tend to be tinny sounding and shuffling
the
movable bits soon stops them.

Yeah, I was convinced this was the ballast as it sounds *exactly* like
that.

The 'free' 6' tubes were good in that they allowed me to evaluate the
idea of LED over fluorescent in that role. The chances are the tubes I
was given were fairly tired (all be it that there were still
functional when taken down) as they were originally on 8 hours a day,
6 days a week (pre lockdown) for a few years.

I believe there is a 3 yr warranty on these new tubes from TLC so
that's handy and if they actually last the 3 years, should work out
cheaper than replacing the fluorescent(s) every 6 months etc?

All my fluoro tubes have lasted decades, not 6 months,
even with the kitchen ones that I used to leave on all day.