The "Original" PSU was not a switching type, the new ones are. Odds are good the old PSU repaired will last 4 times longer than the new switching type.
Chris
Nonsense, ALL a4000 power supplies are switching supplies. You must be thinking of older A500 psu or something?
Switching supplies are quite reliable if they are of quality mfg. the fact that most A4000 psu's have made it 20+ years is proof.