Hi Colin,

Yes, it is across the secondary. Thank you to everyone who suggested it
might be an oil filled capacitor. I'm going to replace it with something
"modern" during my initial efforts to reach "stock" configuration.

I looked at the transformer and it is bolted in with metal hardware and no
insulating washers. Hopefully it was taped up for mechanical resonance
reasons, but I'll do some testing to make sure the case is not hot.

Thanks,

Bruce