Ok I found the key and now I am at the same place your are stuck at. EL doesn't translate to any numbers.
I was just about to to post where the key was haha.
The note for EL-17 does translate to a number.
E = 5 (number of the alphabet)
L= 12 ( Same as above)
Plus 17. This makes 51217. Using this code I was able to get the Left Lock on the door to go Green.
Its the second set for the right I am having problems with. It does not seem to follow the same pattern. I swear i have tried everything.