It depends on the problem you are experiencing with you set.
If the standby light turns on when the set is plugged in, but the set does not turn on (no picture, no sound), and a repeating "fumping" noise, you have a power supply problem. I can't speak for the European sets like the MX-3000, but this sort of problem can usually be repaired by replacing some capacitors on the power supply board. There are high voltages present on this part, even when the set is unplugged - if you have little experience working on sets, it is best to take the set to a servicer.
By "spare parts", I would request clarification from your local B&O engineers. Do they mean replacement modules or circuit boards? If so, this is probably true - the sets are now about 20 years old. If they mean discrete components on the boards required to fix the set, that's a different case. You could always get another MX-3000 on eBay as a spare parts donor if this is truly the case. I've found most repairs only require the replacement of capacitors though.