have a look at this,
https://ep-forum.com/smf/index.php?topic=9530.0you might be better putting them on E-Bay.
I worked for Thorn EMI and we had Delco Transistors in some of our equipment, from the 1990's we used to upgrade some kit. with a transistor & resistor plus To3 mounting kit.
It was done as part of the service call, some engineers used to have the complete pcb as a replacement as they where crap at soldiering.
If I remember right if your voltage at a point on the pcb read 0.3volt you done the upgrade.