I wanted to get an inexpensive bass to fiddle around with, and I found one on eBay...$26 with free shipping. Just got it today. The pots are pretty scratchy and I want to replace them. Problem is, I don't know anything about Bass electronics. Can someone look at this and tell me what I need. They look like they are mini pots. What's the difference between regular size and mini? If regular can fit can I use those? They look to be 500k. What's the A and B? Hope someone can help, thank you so much!