Old magnetic ballast ? Only certain bulbs work ?

First time replacing the bulb on used grow lights I bought.


The current bulb is working

Went and bought a new bulb and it did not work doesnt light up at all and ballast just buzzes.

Went back to store and bought another bulb and it didnt work again but yet the original bulb still works and fires right up .


In the photo the bulb on the right is the new one


I have another 400w ballast same.type but newer and it worked fine replacing the bulbs .


This is an hps ballast and hps bulb I have triple checked all that the wattage is right these bulbs work in digital and magentic .


Only thing I can think of is this ballast is an older one older than the other 3 I have from.2003 any chance there were differnt type bulbs back then or soemthing weird like that ?

New replacement bulbs that wont work in ballast

Anyone have any ideas ? I can see the bulbs are manufactured slightly differnt in the photo but seem to have the same parts overall ..


?

Bad ignitor likely, it's a replaceable part as is the capacitor inside.

Renfro


Thanks a bunch for answering!


Ok makes sense I thought that this may have been the issue (ballast) just seems weird that the old bulbs still work in ballast .


I guess it's safe to say in my case that the ignitor is old and capable of firing and old bulb but not a brand new one .

Wither way again appreciate your help !

Prob time for new ballasts anyway this one is very old .


Thanks

If you have another ballast handy, try the new bulb on that and see what happens.

TBH I have not heard of a 400 watt HPS lamp that would require something special. Maybe a worn arc tube is easier to ignite?

One thing I wonder about is the condition of the socket itself. There appears to be some discoloration on the old bulb threads. Maybe a corroded socket?

Yeah the interior of the socket is nice and clean but it is hard to scree the bulb in ...and now that you mention that the old bulb is hard to screw in I am going to take a further look at the socket today ! Well shortly