Lights Seem Dimmer After Ballast Replacement

Good afternoon all you DIYers.
I had a very productive DIY day. I replaced the tank filler mechanism in the guest bathroom.
I replaced one of those round fuse looking things on a small florescent light that's under the kitchen cabinet.
Now here's the problem on the second florescent light I'm trying to fix.

So the ballast on the larger fixture went out. I took a picture of the bad one and headed over to Home Depot to get a replacement. Picked one that matched the stats on the casing.

I was able to remove, replace, and wire up the new ballast with following the instructions very carefully.

Well, it does light up just fine, but seems dimmer than it used to be. I also purchased new side connectors thinking maybe it's not making good contact with the old ones. Nope, same issue.

Wire connections:

• Connected both yellow ones on one side
• Connected both red wires on the other side
• White with white
• Black with black
• Blue wires not needed since I'm only using one lamp

Here's the old ballast:


Here's the new ballast:



Hopefully someone can give me some direction on what I may to do to resolve this dim issue.

Thanks all!

 

Probably should have converted it to a T-8 tube as T-12's are hard to get, expensive and unreliable.
Even better would be to get an LED tube and have no ballast.

You would only use one yellow wire at one end connected to both pins.
The second yellow wire and the blue wires would be capped off.