The problem is that electrolytic capacitors can leak, even if not used. So, you can store a perfectly good computer and retrieve a ruined motherboard a number of years later. SMD capacitors are bad for this, the MZ80K predates all of that though, and I think only has a few through hole capacitors on the mainboard.
The power supply should also be checked, and in this case, it's safety capacitors which are the risk there, since some of the older ones (RIFAs for example) tend to be hygroscopic, and if they crack they end up blowing next time mains is applied across them. I've not had any problems with power supplies killing the machine with an over voltage, but i've heard this is also a risk.
Anyhow, 45 years or so is time for a recap, and it'll do another 30 years before it's time again...
The power supply should also be checked, and in this case, it's safety capacitors which are the risk there, since some of the older ones (RIFAs for example) tend to be hygroscopic, and if they crack they end up blowing next time mains is applied across them. I've not had any problems with power supplies killing the machine with an over voltage, but i've heard this is also a risk.
Anyhow, 45 years or so is time for a recap, and it'll do another 30 years before it's time again...