Testing Power Supplies! Re: Norsk Data Nord-10/S restoration effort on the way!

Joe> Testing power supplies before powering up a system is just plain Joe> paranoid! (And I'm trying to be polite here!) There are a Joe> thousand parts in modern computers that can cause just as much Joe> damage!!!!!!!! I disagree -- at least in the case of linear regulator supplies, which is what you'll normally find in a classic computer. A very simple and very nasty failure in a linear regulator is a short in the pass transistor. If that happens, you get a much higher output voltage, and there is no current limiting. It's a fair bet that this will fry a large fraction of the semiconductors in your system. If the supply has a "crowbar overvoltage protection" circuit in it, that's a different matter. But testing a linear supply is trivial. So why not do it? If you let the magic smoke out of the computer, it's too late... paul