After going through all the macs I found 3 drives that wouldn't boot. And they did when I stored them.

2 gave constant restarts.........1 has come back to life

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these drives were never opened and wont open them for a while. No clicking.

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hoping its just bearings on the platter

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took all the rest out and stored them facing the same way up as in the mac.

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see what happens!

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from the failures I have seen with liquefying seals and the overall age of the drives  I don't think there is any method to keep these devices working for decades!