Mesa Mark IV snubber cap not on schematic?

[schnarf]

I'm repairing a Mark IV that was blowing fuses, and I tracked it down to a 0.047uF 600V 715P cap that goes from where the "A" HT supply and the OT center tap meet on a terminal strip, to ground. Effectively it's in parallel with the .1uF 1kv "UL" capacitor. It's failed and it's easy enough to replace.

What I'm curious about is, this doesn't show up on the schematic, but I do see it in other peoples' gut shots online. From what I can see, it also looks like it's in the Mark III! For example, in all the pictures here, it's the in the circled at the top center of all of these photos, up near the recording out jack: https://www.rig-talk.com/forum/threads/mesa-mark-iv-a-bs.300533/

So I'm just wondering, out of curiosity, does anyone know more about this component? Has anybody else noticed that it doesn't show up on schematics (even the community-made Mark IIC+ and Mark III ones as far as I can tell)? Is it known to fail and is anybody in the habit of replacing it with a higher voltage one?

Thanks!

 

[stephen sawall]

I have heard Mesa schematics are often wrong. Funny I was just talking with a friend about the IV schematic the other day.