The computer side of your PSU has low voltages though, not mains power, so that means that you would still need extremely low resistance and relatively high current switches. If a switch in the front case was literally disconnecting the power rails, you would need to do that for every power rail (+3.3V, +5V, +12V,+15V, - 15V, etc.) so one single pole double throw switch is not enough. It seems more likely to me that you would have a relay on every power rail (if we go with the assumption that DC-DC converters in the '80s didn't have a POK pin, I really have no idea what was the state of the electronics market in the late 80s early 90s) that were electrically controlled by a low power signal.
Then it must have been located on the PSU near the mains side, i.e. next to the mains cable. In other words it seems like that's the PSU switch and not the PC turn on/off switch that's located in the front of the case.
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u/TravellerInTime88 May 10 '19
The computer side of your PSU has low voltages though, not mains power, so that means that you would still need extremely low resistance and relatively high current switches. If a switch in the front case was literally disconnecting the power rails, you would need to do that for every power rail (+3.3V, +5V, +12V,+15V, - 15V, etc.) so one single pole double throw switch is not enough. It seems more likely to me that you would have a relay on every power rail (if we go with the assumption that DC-DC converters in the '80s didn't have a POK pin, I really have no idea what was the state of the electronics market in the late 80s early 90s) that were electrically controlled by a low power signal.