January 31, 20120 found this helpful
I was just told that the 'non-replaceable' bulb has a built in fuse. When the fuse blows, they purposely don't want you to be able to remove the bulb and white base for safety reasons. That's apparently why they say replace the whole string.
That said, it seems to me that the bulb could blow without the fuse blowing. I'm assuming that the bulb in the white socket is the same as all the others. (True?). But you can't replace that bulb if you can't get the white base out of socket! Some folks have talked about forcing the base out and replacing the bulb that way, but I think you're asking for safety issues.... 'you're playing with fire'... maybe literally! :) Any time you try to bypass or play with a designed safety mechanism you're asking for trouble. You're in an unknown area where you are using something in a way which it was not designed to be used.
Bottom line, to me at least, is that all these light sets on prelit trees (and loose strings too) are not meant to last forever. Some, maybe all, of these light strings have labels that say they are only to be used for 90 days! So putting an unremoveable fused base in a light string serves the purpose of making sure that these lights are not used 'forever' and are taken out of service after a while: Either when the fuse blows or when the bulb in that base burns out.