Funny thing, I just had both my radios ('87, '90) out today for activities unrelated to the lamps. In any case, there are numerous small bulbs in the radio, soldered onto a printed circuit board which also carries function switches. Unfortunately replacing them appears to require desoldering two large ribbon cables in order to gain full access to the back of the board, which makes it pretty much hopeless to replace the bulbs unless you've got excellent soldering skills and a lot of time on your hands. In my case I'm undecided about whether to simply add some LEDs (appears possible, lots of room, nothing special about optic coupling to lamps) or eventually junk the radios. I'd rather not do so because I actually like them and don't particularly want or need a CD player.

The vacuum flourescent display (frequency, time, etc.) often fails on these as well. In my case (the reason for removing one of the radios today) there was a solder joint on the display module that was defective from the factory. Reflowing the joint fixed it.