My computer monitor (Samsung Syncmaster 732N) started to fail and it seems some capacitors have gone bad. They are all electrolitic but one is a CARLI MPX40 .47K275V-X2 capacitor, which where I live (Argentina) turns out is very hard to find.
I didn't know what an X2 capacitor was so I researched a little bit and it seems they are capacitors designed to be used as filters in the power line, and because of that, they have to meet higher standards of endurance regarding temperature, voltage surges, etc. Is that correct?
My question is, suppose I cannot get one of these where I live. Is there a suitable replacement component or circuit that would meet the same security standards? What could happen if I just put a common .47 electrolytic capacitor? Could it blow up or catch fire or something?
As @Marko implies in his comment, the chances of an X cap failing are very low.
Electrolytics, on the other hand, have a definite lifetime that is relatively short when hot. Presumably you are shotgunning and have limited test equipment- even so you can check the X cap with a regular multimeter. If it measures open on ohms and has close to the desired capacitance it's okay. If you don't have a capacitance range, use the highest ohms range, touch the probes until the meter goes off scale, then reverse them. There should be a short delay before it goes off scale again (because of the capacitance). Anyway, a bad X cap (unless shorted) won't prevent your monitor from operating.
Ideally you check electrolytics with an ESR meter, but you can just replace them all. The biggest ones and the ones close to hot stuff are most likely to be bad (and anything with a suspicious bulge or fluid leakage, of course). Don't confuse the 'gunk' (typically white, off-white or brown) that manufacturers often use to mechanically stabilize through-hole electrolytic caps with dried electrolyte leakage.