[Ron Ramirez]

I think this is the bulb you need to illuminate the set's grille area:

http://1000bulbs.com/product/5771/IN-0015T7INT.html

It seems to me that the intermediate base is the right size, but I'm not 100% positive on that. I do recall that the bulb I bought for the 15X I used to own had an envelope shaped just like the one in the link above. I remember that 15X had an old bulb in the socket that was burnt out, and the bulb was frosted. I could not find a frosted bulb then. But at that time, the Internet was just getting started so it wasn't yet easy to find almost anything you would ever need or want on there.

If a candelabra based bulb is too small, an intermediate base should be the right size.