Looking for tiny incandescent lamps for my TM-451A Kenwood.

Apparently these are 6 V or so; there are four of them in series parallel
controlled by a regulator to vary intensity. They light up the LCD and two
of them are burned out.

I have searched many of the usual sources and can't seem to locate
replacement lamps; as a last resort I could go to Pacific Parts but they are
so expensive. These are just inexpensively made tiny bulbs with wire leads.

Any suggestions?

Bob