On 21/05/2017 00:07, Rod Speed wrote:


"Fredxxx" wrote in message
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On 20/05/2017 23:14, Rod Speed wrote:
Fredxxx wrote
Rod Speed wrote
wrote
R D S wrote
Phil L wrote

Is there a starter? - 35p each, I'd try this first

Thought the same, done that.

So you've got switchstart fittings. Then it's wrong starters,
bad tubes or bad contacts. The capacitor can't cause this.

Corse it can.

And is in fact by far the most likely problem when the tubes
arent connected in series after the things he has tried already.
The capacitor will be across mains in.

Yes.

Good, we have got that far.

Can you explain, assuming the supply impedance is in the order of a
fraction of an ohm, why a capacitor can cause the perturbations in
voltage supply to cause a substantial flicker?

You havent established that it is causing perturbations in the voltage
supply. And it can obviously do that by not being a viable cap anymore
anyway.

Is that an admission that its not the capacitor?

Nope. If the tubes arent in series, that is by far
the most likely cause of the problem given
what he has tried that has made no difference.

Or are you thinking of some other capacitor characteristic that might
cause this flicker,

Failure mode of electros, yep.

Electros? Is this a new component technology?

Certainly electrolytic capacitors are rarely used across AC mains, so it
must be some other capacitor technology.

if so do tell.

Most obviously if its got a significant partial short
now, as electros sometimes do when they have failed.
That could easily see the tubes no longer getting full
mains voltage anymore, and so flicker now.

Are you now suggesting this partial short will be causing perturbations
on mains voltage? Previously you said we haven't established that such a
"partial short" would cause "perturbations in the voltage supply". You
really ought to make your mind up.