Power interlocks (was Re: [OT] Alphaserver Oops!)

Jeffrey l Kaneko <jeff.kaneko(a)juno.com> wrote: They certainly don't *ALWAYS* cause more problems than they solve. Some interlocks are very important. For example, some of the interlocks on vacuum column tape drives are to keep the tape from winding up in a tangle all over the room (and in an extreme case possibly strangling someone). Some computers can actually be damaged by operation with interlocks disabled. For instance, one site disabled the door interlocks on a VAX 8600 while trying to repair it. This led to the thermal sensors shutting it down. So they disabled those too. It'll be OK for only a few minutes, right? No, they had to replace about $15K worth of boards that failed due to overheating. All because someone thought they knew better than the system designers and could debug a problem on the cheap instead of calling in a qualified field service engineer. I'd suggest defeating interlocks only if you are *sure* you know what you're doing, not if you *think* you know. In the case of the Alphaserver that was cited in the earlier email, it is clear that the person opening the machine did NOT know what was inside it, and it would have been entirely inappropriate to defeat the interlock. Eric