Rich, you know how on pc power supplies there is usually a +5v, +12v, sometimes a +3.3v, etc....outputs, those are referred to as rails. Sometimes when a psu goes bad only one of the rails goes bad, say the +12v....
PC power supplys seem a lot simpler to troubleshoot than the power supplys on the HR24s, but I don't think it really matters (to me, at least), if the front panel lights don't work the PS seems to be bad. I've only replaced 3 boards, but all 3 boards turned dead 24-500s into working 500s. To me a ten minute job to fix something is better than spending hours troubleshooting components.
I've done a lot of troubleshooting and it was always under pressure. Nobody cared what I did as long as I got the equipment running. I just never had time to "fix" a component part.
Appreciate the explanation, that was a good analogy.