I've built my new PC, but it won't power on at all! I've double-checked everything and even tried shorting the power switch pins, but still no luck. I tested the power supply using a paper clip method; the PSU fan gives a slight jerk and clicks, but that's about it. I measured the voltage on the 24-pin connector with a multimeter, and everything seems okay, except for the 5V VSB wire, which is only giving me 1.5V and fluctuates up to 2V. I unplugged everything not essential, leaving just the motherboard connected, but I still can't power it on, and it shows the same low voltage on the VSB. The resistance on the VSB pin to ground is around 2400 ohms. Do you think this indicates a short in the motherboard, or could it still be an issue with the power supply? Is it necessary for the motherboard to receive a steady 5V to power on?
2 Answers
I had a similar issue with one of my builds. It sounds like your motherboard might not be getting the proper voltage it needs to power on. That fluctuating voltage on your VSB line could hint at a problem with either the PSU or the motherboard. Since you’ve already checked the PSU to some extent, I'd recommend trying another power supply if you have access to one or testing yours on a different setup. Also, make sure the power connections are seated properly — sometimes it’s the little things that can trip us up!
From what you described, it sounds suspiciously like your power supply is struggling. The fact that you're seeing low volts on the VSB line suggests it might not be supplying enough power. I’d definitely look into testing your PSU under load or swapping it out. And yes, typical motherboards do need at least that 5V to boot up, so that low reading is definitely a concern!
Totally agree! I've experienced similar issues and ended up getting a new PSU, and it worked like a charm afterward.
Yeah, I had a similar situation where I missed a connector completely. Also, try reseating the RAM and CPU. It's a hassle, but it fixed my problem!