That is true. but fortunately it doesn't take long to get the board out of them. It is a little more work, but no biggie. I keep a Raytheon book around, it is an old book but has a lot of cross references for replacement chips, but you are right, even then they are a bit hard to find. I don't do that much of that stuff now anyway, I mostly just maintain my own gear or by the occasional basket case and restore it. But given how inexpensive extremely good gear is now, it is hardly worth the trouble. In a lot of situations with newer amps it is just as easy to order a new circuit board. I've got a Carvin 50 watt amp that has a board with the tube sockets in it that is a board used in a bunch of other amps. I didn't replace the board, one of the guys in the band I am in rebuilt it, but it was available a couple years ago.