On Sat, 21 Apr 2018 03:02:11 -0700 (PDT), wrote:

snip

the starter is faulty.

Well, 3 of the 6 could be considered so as they fail to even start the
tubes from cold but the first two that caused the tubes to flick off
now and again, may just be considered 'under spec' ?

It should never interfere once the tube is lit, at least after the first 2 seconds or so.

Agreed.

Unless the tube is absolutely on its last legs, which you'd see by increasinly severe flicker every so often then the starter kicks in.

Ok.

Then it runs ok for a bit then goes into flicker again.

New tubes (now) so not that in this case.

And that's the ting ... I've been installing and maintaining such
fittings for many years now and it's not the first time in the 20
years (or whatever) those fittings have been in the kitchen that one
has started to misbehave and I've had to sort them.

The first and obvious trick is to swap stuff about between the two
fittings, and / or just pull the starter once the tube is on etc.

It was just I was interested to find out what could cause a
potentially good / new starter to start to misbehave but only after
(it seemed) a few hours.

Now I'm a little clearer how the system works (thanks Andrew) I can
see how a 70W tube could be 'pushing' a starter marked 4-80W (as it's
actually likely to be rated as a 4-65W).

I'll put them back in and note the supply voltage when they are
working fine and when they aren't and see if there is any correlation
(when I believe there is more chance of them misbehaving if the input
voltage is low).

All for the S&G's etc.

Cheers, T i m