Fluorescent strip lamp units - help me fix them?

[julianf]

I Just tried to install a couple of units that someone gave me (used) some time back.

They are both dual bulb units. About 48" long.


So, i wire it up - only one side lights (and that takes about 10 seconds).

I swap the starters - same side lights (ie no change)
I swap the bulbs - no change (still same side lighting)

I get the other unit - wire that in. On this one, only one bulb lights (happens to be the other side)
I swap the bulbs - no change
The starters - no change

Getting frustrated now.
I swap the transformers. No change. Still the same (physical) side lighting, and, on both units, it takes about 10 seconds.

The terminal block that takes the mains in is a push lock one (push, and insert wires, then release)
6 terminals (3 pairs) - i assume they are in commoned pairs, but, in case, if tried wiring to the other sides, and, no change there either.


The only common part to both bulb/starter/transformer combo is the capacitor. I assume it *must* be this?

...but i know zero about these things. Am i just being an idiot somewhere? (and what's with the bulb that does light taking 10 seconds to do so?)

 

[awemawson]

In the above circuit, which is the usual connection for these things, the ballast is what you are calling the transformer (it's actually a choke) and there is no capacitor. Capacitors are added to correct the power factor of these lights, and are not needed for them to function, and are usually just wired across the input. (Just occasionally they are wired in series to prevent people just removing them and getting cheaper electricity!)

What happens is the starter begins life 'closed', and current passes through both filaments and is limited by the ballast (choke). The filaments glow and emit electrons, and the starter goes open circuit. Electrons flow through the vacuum of the tube, and strike the inner surface, which fluoresces and gives off visible light. The electrons striking the filaments keep them warm enough to keep supplying electrons to keep te process going.

Knowing how it's wired and how it works should let you diagnose your problem

 

[brightspark]

have u tried changing the capacitor from a known light that both work on. what size starters are fitted they should be about 4 to 80 w fsu .are they the new slimline tubes or the old fat ones and what is the wattage of ballast and the tubes

 

[julianf]

Ill go take some snaps...

(thank you)

 

[julianf]

Ive not got one of those fancy phones that joins stuff together, but you get the idea, im sure -

 

[awemawson]

So your capacitors ARE directly across the mains, and unless it's blowing fuses they are NOT your problem

If you really have interchanged tubes, starters and choke and the fault stays the same then you are left with a bad connection somewhere.

I'd check the starter contacts and then the tube contacts followed then (desperation) the wiring it self.