There is a light gauge secondary, presumably about 18V ac , full wave
rectified to give 25.2 V dc for the seriesed heaters of 2 ECC83, CTs N/C.
The main secondary winding supplies the TO3 o/p devices and a diode pump for
the valve HT. Not determined where the opamp supplies are from.

Putting 20V ac on the heater supply gave 50 V on main and 96V on each
primary
Putting 20V on the main gave 7.6V on the heater one and 38 V on each
primary.

I assume from this the primaries are ok and something wrong with the main
secondary, perhaps 2/3 of the run is shorted somewhere, 1/3 only functional.
Luckily they always dilute the epoxy infill with chalk or something so easy
to chain drill out. Nothing obviously wriong with the outer layer of
secondaries but I assume the problem is due to only one layer of polyester,
half overlapped on the outside and only that separates squashed secondaries
right up against the metal top of the 1U case. Rubber disk on the bottom
face of the toroidal but nothing at the top other than the standard toroidal
polyester wrap strip. At least they did not decide to pass the coach bolt
through top and bottom of the case. If the secondaries are re-windable (if
no primary damage) then some extra padding will have to go in over the Tx
and some extra space found in the cab.