Footswitch w/led and no battery?

[fattcamp]

Hey all. My old man recently commissioned me to fix a switch for him that is used to turn on and off the fx from a board. I've never worked on anything like this before. I've built stompboxes/synth modules etc... this looks incredible easy but im sort of perplexed.

It's an old marshall single stomp footswitch. it's got a single led/single resistor and the 2 wires from the mono cable wire onto a switch with 3 lugs. From what I've gathered, you can run the unit with led and all as long as it's pulling it's power from another source... apparently this is what they were doing as they've never used a battery in the box before. I was just thinking of replacing the led/resistor as they appear with the naked eye to be possibly fried. I'm wondering if anyone can shed some light on this and if so, what value of resistor I should be using.

I've used this many times before to calculate the proper series resistor for led's (http://led.linear1.org/1led.wiz) but not sure if it'll be much help on this one. Hope someone can help out a bit with this one. thanks in advance

-dave