Well, replace the capacitor if you know how to solder,have all the tools,and understand that you could damage the board even more. Not to sound pessimistic but I have been doing electronic repair on a component level for more than 20 years,and it is very easy to rip a trace or damage a component next to the bad cap.
That being said. If you want to try it out, my suggestion is to find a broken radio or other small electronics, take it apart,and try to remove some of the components on that first. Soldering like any other learned skill takes practice. Also you might want to look into getting some "chip-quick". Its an alloy designed to lower the temperature needed in de-soldering. You will need if you don't already have, a soldering pencil,solder,braid,pump and if you like the chip quick. easily $40 to $60. A replacement board would run 50-75$. Considering the age of a 939 board, this might be a good time to think about doing an upgrade.