As well as dealing with immediate problem and other issues, like
perished rubber drive bands to hold (just ) the tank in place and
sometime thereafter free to fall amongst all and sundry.
The BDV64B and 65B are presumably held with epoxy to their vaned
heatsinks, nothing mechanical. 30 years integrity of epoxy? I assume I'm
duty now bound to add fixings, after trying to prize apart one with
fingernail insertion, still holding. Was this a common practice then and
reliable since, or would it be zinc oxide white goo bonding, to some
extent, over 30 years and original reliance was just on the transistor
leads not bending with vibration etc ?
The vanes are screw fixed to the pcb but not transistors to heatsinks