[Arran]

It sounds like it's time to pull the power transformer and have a look at the leads, they may have some breakage in the insulation, and in the wires themselves that may be causing shorts, barring that there may be some other fault like a shorted bit of hookup wire elsewhere, or a wiring error. It's unusual to have a failure in most Philco power transformers without an external cause.
 The model 96 was a screen grid tubed TRF set, prior to the 1931 model year this was the top chassis that Philco produced, it even has AVC, so they were good performers. The main issue with TRFs is dial tracking, there is just no way to get every station spot on, which was why many of these radios didn't even denote frequency on the dial, just 0-100.
Regards
Arran