They condenser is the key - most likely to fry, hard to replace.
OBTW, you have listed the makings for the threat ...
Unless one is expecting to get a pulse every freakin day or sumfin, replacement capacitors can be home rolled with wax paper and aluminum foil. In a circuit they can be protected with back to back Zener diodes rated higher than operating voltage but lower than maximum withstanding voltage.
Cat whisker on galena can work, but it is a pain. Better to have a stock of diodes kept wrapped in foil or something.