T5 bulbs wont light, need help.

[NorthernCoral]

I recently bought a 6 48" bulb 2 ballast t5 fixture. All bulbs were working and then I switched most out. All of the new bulbs on one ballast work but on the other ballast no bulbs will light. Checked these bulbs on the working ballast and no problem with the bulbs. Is the ballast dead????? How would simply changing the bulbs do this?? And the fixture is apparently almost brand new. The fixture is a solarflare by acuactinic.