T5 ballast issue?

[TiggrReefer]

I am refurbishing a light hood with 8 T5 bulbs; 4 ballasts;
I have all new bulbs
4 bulbs (2 ballasts) appear to be working properly.
The other 4 will light for a second and then go out
I am suspecting a ballast issue
How do you test a ballast?
Can I replace the two 2-bulb ballasts with one 4 bulb ballast?
Thoughts?

 

[Troylee]

Ballast or end caps… swap the bulbs and it will tell you if it’s a ballast.. grab the bulbs that aren’t on and twist them slightly and see if they come on.. if so that’s a end cap..

 

[TiggrReefer]

They come on, but only stay on for 1-2 seconds