LM709C opamp replacement

[pjpoes]

Hey Guys, I have a Thorens TD125MKII. I'm having problems with it getting good numbers and propper adjustment. It has been suggested that possibly the opamps or transistors are bad, and that I should try replacing them to see if that fixes things. Given that the parts used are all very inexpensive, I was wondering if anyone had any thoughts on what might be a good replacement.

The LM709C is still in production, so I could replace it with the same opamp, but if I'm bothering is it more sensible to find a more modern drop in replacement with better numbers? Is there a modern drop in replacement with better numbers?

As for the transistors, they seem to be priced at about 24 cents a piece. the part numbers are 2x- 2N2218A and 2x- 2N2904. Are these fine for the job as a motor controllor, or again, are there better modern drop in replacements worth looking at? I know a lot of people in the past said don't replace them they are fine, but like I said, now that I am having trouble getting the adjustments right, and it looks like replacing those parts is necassary, should I use the identical original parts, or better modern replacements. Thank you.