On Fri, 22 Apr 2016 18:44:11 -0700, Phil Allison wrote:

** Going short circuit is likely the result of one of the capacitors
across the AC line failing - generally these are "class X" types which
have a limited life expectancy. The other possibility is the "common
mode" choke but that is very unlikely.

Yes, most like a cap.

** So the equipment IS rather old ? Like 20 years +

Almost always. Typically 70s & 80s. I can't deal with SMDs anyway.

** Small SMPSs can use a resistor in series with the supply to limit
surges - say 5 or 10 ohms, wire-wound. Otherwise it is normal to use an
NTC thermistor with similar cold resistance values.

Noted, thank you.