I found a nice 1953 Western Electric 500C/D with all matching date codes. I want to fix this one up and use it. My problem is that when I first plug it in with the handset off, I have a dialtone for only a couple of seconds then it fades out. Any ideas? Could this be a bad capacitor?

Also, this unit has a 3-wire network connection. Is there any modification that is needed for the modern 2-wire connections being used today to make everything work properly? It still has the origional 3-wire network connection line-set.