Reviving elderly BBC Micros

So I have recently been given half a dozen Acorns - one Model A, 4 Model B+ with 64K and one 128K B+. I'm going to donate the Model A, at least, to TNMOC at Bletchley, but I'd like to keep at least one for myself. The thing is, whereas I wouldn't just turn on a 1980s business computer with multiple moving parts, the donations chap at TNMOC has put The Fear into me by sternly warning me Not To Turn Any Of Them On, because They Will Blow Up. So, how does one go about testing a mucky old Beeb that's not been on in 25y or something & has been stored in a dusty attic? Give it a good clean, I guess, but can one hook one to a PC PSU and test its internal PSU in isolation? -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Tel: +44 20-8685-0498 ? Cell: +44 7939-087884