Roland. a gas tube arc will not affect the low voltage PS so one of the relays must have failed but since they are in series both would fsil if one went open coil. I suppose the failure was acutasl contacts allowing the resistor to pass current (not shorted). Your customer seems to have some problem with something causing all these different amps to fail. If it is his 240 line voltage he needs to monitor it or have the POCO check it out.