'85 P Bass Lyte blend pot replacement question

I have an '85 P bass lyte. The stem on one of the pots broke. Under the hood it gets more complicated than I can grasp.
The pot I'm looking to replace is the only pot that is not wired directly to any type of circuit board. I'm thinking it is a blend pot. On the side of the pot I read "500 K(ohms symbol)A" and directly underneath that, "500 K(ohms symbol)C". Looking down at the pot from the player's view, there are four pots, two pots in two rows. The pot in question is in the row nearest the floor and is the pot on the left.
I replaced it with a blend pot, (Alpha Blend Pots, 250K-ohm Item # 4137). The result was at the indent the bass produces no sound. The further from the indent one goes the more volume is achieved. The volume is all neck or all bridge depending on which way you turn.
I'm no stranger to getting things wrong.
Here's a pic of my handy work, and a diagram I grabbed from the web.

P Bass Lyte Blend Pot by Stephen Simon posted Jun 22, 2016 at 5:21 PM

P Bass lyte Electronics by Stephen Simon posted Jun 22, 2016 at 5:20 PM

Any advice would be appreciated.
Thanks,
Stephen

 

Hey line6man,
I got it working, thanks to your advice.
BTW, just bought a Line 6 Lowdown LD300 a few weeks ago. I really like it.
Thanks so much for your help.
Stephen