Trigger shifters - servicable?
I am currently riding an old, ancient, mongoose bike while waiting for my new good bike to be ready at the shop. As the weather has been getting colder, the shimano trigger shifters on the have been starting to slip. Everything seems to be aligned correctly in all the gears; cable line looks good, and no tendency to start to slip to another gear. However, the lever used to push it in the higher-tension direction just doesn't want to catch all the time. Seems to be worse when colder, oddly enough.
Has anyone tried to open and service these things in the past? I'll probably take it apart and play with it once I have my new bike... but if anyone has some thoughts or tips on servicing, I'd love to hear them.
I'll post some pictures if the servicing is successful.