On Saturday, 27 May 2017 18:17:44 UTC+1, Johnny B Good wrote:
On Sat, 27 May 2017 05:23:28 -0700, tabbypurr wrote:
On Saturday, 27 May 2017 12:52:10 UTC+1, Fredxxx wrote:
On 27/05/2017 11:52, tabbypurr wrote:
On Saturday, 27 May 2017 03:49:09 UTC+1, Johnny B Good wrote:

BTW, I can't figure out how a *single*
starter can be wired up to start a double tube fitting.

I don't believe it can

Given the 4 heaters need preheat to strike, I don't believe you can
have just the one starter either.

Practically, no. If desperate one could make it work with only 2 getting
preheat, but it wouldn't do tube life any good.


The point I was making was that the OP only mentioned trying a
replacement starter (*singular*) which implied some cunning circuit
topology where both tubes could be started using just a single starter
switch. However, once you've resorted to that sort of complexity, a
starter becomes redundent since you're now into the territory of twin
tube quickstart and rapidstart ballasts which can fire up the tubes
without any such switch starter devices.

Rather than speculate any further, I'll await the OP's response to
clarify the situation for us. I'm anticipating that he'll confirm the use
of a pair of starters and that the unit won't even attempt to light up
either of the remaining tubes once one of them has been pulled from the
fitting.

Of course the OP requires 2 starters, unless it's a cobbled together fitting of different ballast types, or some homebrewed oddity.

You can start 20w tubes by simplifying the setup rather than complicating it... just remove the starters & use an LC ballast instead of L. The resulting raised starting voltage slowly increases tube current until it lights properly. Done that before.


NT