[deshawn]

I just noticed something odd with the output tube on my 50-922. The one I have is obviously burned out. I ordered the new tube from the schematic. The schematic says that it is a 50L6GT tube. When the tube arrived today, there is quite a discrepancy in size. So I looked at the old tube. It's a 50C5.

So... Lesson learned: look at the actual tube before ordering!

It appears that there was room on the chassis for a 50L6GT socket, but a conscious decision was made at some point (by Philco, because this socket is riveted to the chassis) to replace it with the smaller 50C5 socket.

So I have a couple of questions:

1) How common was this practice of replacing tubes? The nostalgia air schematic shows runs 2 and 3 of this radio with a couple of different parts, so the design seems to have evolved over time. Is this an evolution that might have shown up in a later service manual?

2) Do I just order the 50C5 and assume this was a design change?

Thanks again! It's great to have this forum with so many of you so willing to share your knowledge!