lighted door key hole doesn't work

I have a lighted key hole for the door lock. It does not work. I see that there is a bulb connected to two wires. I tried to replace the bulb with very small wattages and it just blew the bulb. It looks like it was saudered on. They don't make any parts for this. Has anyone had this problem and able to get the door lock key hole lit? Also, they sell fiber optic key holes is it compatible? Lastly, would anyone be willing to sell their working lighted key hole cylinders with bulbs? If so please let me know. I know this is minor, however, a really neat feature. Thank you.