Simple question....

[mark312]

Hi from an electrics simpleton.

I have a wall mounted backlit display unit, that has 4 T8 fluorescent strips linked to a single internal ballast. The problem is that when I switch it on at the socket, two of the tubes flash once for a split second, and then nothing. If I switch it off and then back on again, nothing happens unless it is left off for some time.

This leads me to assume that it is the ballast unit that has failed, or should I try replacing all the tubes to see if that works?

I don't want to buy 4 tubes unnecessarily if it is a faulty ballast, and I was hoping that someone more familiar with flourescent fittings could diagnose the problem for me.....

Thanks for your help

 

[oo7]

Swap the two good tube over with the bad ones and see if the problem follows the tubes or stays in the same place. If the problem moves with the tubes replace faulty tubes, if the problem stays in the same place check the starters.

 

[ericmark]

There are many configurations of a ballast. From HF with dedicated output to each tube to pairs of tubes, to all four the T8 is a small tube. The starters if any also have some odd things where so called universal starters will not work with paired tubes. There is really no one size fits all.

In the main when lamps fail it is normally down to the tube but often swapping a starter or ballast will for a short time fix the problem. So normally I would change the tube then starter then ballast and likely if you find changing tube does not work it's not because the tube is not faulty but that the faulty tube has caused the ballast to fail.

 

[mark312]

Swap the two good tube over with the bad ones and see if the problem follows the tubes or stays in the same place. If the problem moves with the tubes replace faulty tubes, if the problem stays in the same place check the starters.

There are no starters in this unit. I will try swapping the tubes.