Need sub test settings for 7b5/7c5 loctals

[Tubejunke]

I have a Philco model 42-350 which employs a 7B5 loctal tube. I'm not sure of its function in this particular set (no schematic), but the FM band doesn't work, so I wanted to test the tubes. I have older and newer testers and neither recognize the 7B5 or its sub. the 7C5. I wonder if anyone has run into this and knows of another tube that's settings would be similar.

The FM band is some sort of early version that only goes to 99 Mhz, but I should still be able to pick up stations up to that point. Any advice on the tube would be great! Thanks!