I have been running a 400w Philips MH bulb on this convertible Cooper balast for a few weeks and now its time for the HPS bulb to have its turn. Problem is the 400w Plantmax High Pressure Sodium bulb that I bought is not turning on. I yielded the warning that the bulb may need time to charge up. How long should the charge take? Anyone heard of this problem before?
Not sure why your bulb doesn't work... But I use Plantmax bulbs in my grow with no problems. Might just be a bad bulb.
How long do you wait for the light to charge? With the MH it didn't take longer than 5 mins and I left the new one in for over 2 hours and nothing happened.
My bulbs fire up right away. When the timer clicks, the bulb fires up, flicker for a few seconds and then start to brighten. That's it.