Dear Fixers

I have a lovely Sony Trinitron monitor that has suddenly died, and need
some experienced insight please.

A few weeks ago the monitor died and I found that the LOT driver 2SD1887
had gone short circuit.
Not realising that the line output stage and the EHT circuit had
different driver transistors, I searched my junk and found a 2SC3897
which looked very similar when comparing datasheets.

I fitted the new transistor and the set burst into life and has worked
happily for about a month.
However it died again and the PSU was 'wailing' like crazy.
This time both the EHT transistor (2SC3897) and the 2CS3997 (line
deflection transistor) are short circuit.
I wonder if there is a stock fault that anyone can give me a hint about?
Alternatively ..is it possible to get hold of/buy this part of the
schematic somewhere?
It seems a shame to have to 'bin' such a lovely (and up till now) trusty
monitor.

Can someone help please?

Thanks in anticipation....Dave