Chapter 3: It won't just kill you it will also hurt while you're dying

Next was the power supply. You're not meant to open them up and I don't like doing so. They contain a mix of mains voltage (which is 240V around here) and big capacitors that meat-bags like me don't really like. Since it wasn't plugged into the wall since I got it almost a year ago, I was less concerned about getting zapped, so I opened it up the free the internal fan an components from dust.

I'm aware that you shouldn't use a regular air hose on electronics because sometimes the air can be electromagnetically charged or just very moist. If I'll ever be working on a one-of-a-kind PC prototype I'll keep that in mind. For most of-the-shelve machines I don't care.

After cleaning it out I could hock up a multimeter, bridge the soft-power pins and plug it into the wall to check if all the voltages are plausible. Since there's no load on it I expected them to be a bit out of spec. It didn't blow up after turning it on and the Voltages where fine. I even set up a Camera to film in case I get some magic smoke.

A hand holding an air gun pointed at the inside of a PC power supply.

A photo with a multimeter, a PC power supply and a phone showing the pinout of the PSU.

5.244 volts shown on a multimeter.

11.89 volts shown on a multimeter.

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While at the topic of power, I also checked out the Clock Battery, a Rayovac 480. According to the service manual it should be replaced when it falls under 3 Volts. Mine was at -0.32 Volts, which is definitely a voltage. Because those batteries aren't made anymore and faithful clones are expensive, I decided to replace it with a triple-AAA battery holder which will output roughly the same voltage.

A screenshot from the official service manual showing how to measure the voltage on the battery.

-0.32 volts shown on a multimeter.

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I didn't have any battery holders on hand, so I had to order some. For continuity's sake I'll act like I put one in right away. Because the wires on the battery holder where a bit short I cut the wires of from the battery and soldered them together. That way I also didn't have to crimp on a new connector.

A rectangular battery sitting on top of a pcb with its cable wrapped around it.

A rectangular battery with it cable cut off and a battery holder next to it.

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