Question Chances PSU fried the system?

Aug 13, 2020
Did something stupid after cleaning dust out of my PC. Forgot to turn the PSU switch to "Off". Proceeded to plug it in while the switch was on. Saw and heard a spark from the PSU power cable. The PSU power cable is connected to a strip into an outlet. I quickly unplugged everything, switched PSU off. Then slowly proceeded to plug everything back in after a few minutes. After everything was plugged in I switched the PSU switch to "On" and heard arcing noises. I then tried to power on my PC but nothing powered on. I suspect the PSU is dead at this point. Then immediately turned it off and took apart the PC to examine each component for any burn marks and smells.

GPU and RAM seem fine, not picking any unusual burn smells. The MOBO doesn't have any suspicious burn smells as well. I disconnected the PSU and plugged it in (SOLO) into an outlet and powered it on and heard more arcing noises and sometimes small pops coming from the PSU outlet near the power switch.

What are the chances this stupid mistake fried the system or damaged other components? I'm pretty certain the PSU is the main problem here. Most likely the PSU failed and died. I have been meaning to upgrade it for over a year now just did not have the time to do it, it served me well as well as this PSU is nearly 8 years old. I am more concerned about the other Components than the PSU here, I would appreciate if you guys could share any recommendations or similar experiences or things to look out for as well as if you could give some recommendations for a new PSU in the $80-$120 range. I primarily use this PC as a "At-Home" trading desk for Equities and Futures markets as well as Video Editing.

At the moment I don't have any backup PSUs to test all my components out, so I'm hoping for the best.

GPU: MSI R9 390 8GB
CPU: Ryzen 7 2700
RAM: 64GB Ram Corsair Vengeance LPX
MOBO: MSI x470
PSU (Dead): Coolmax Power Supply ATX 700 Power Supply - ZU-700B

Note: Yes I know the PSU is an ancient POS. I've had this rig for over 8 years and it ran with no problems until today
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My thought is that the PSU likely "took the hit". Especially being 8 years +.

Before continuing: do you have all important data backed up and proven to be recoverable and readable?

If not, do so. You may need to remove the host drive, install in an external case, and connect to another computer.

Objective is to ensure that the data is preserved before you proceed with any potential solutions.

Testing a PSU:

New PSU - start with the following link:,4229.html
Aug 13, 2020
Yes I disconnected all the hard drives. I have most of the data backed up on external hard drives which I run backups on once a month. I have one hard drive i'll use as a "test" when powering it up with a new PSU.
Plugging in the PC with the switch in the on position could cause arcing but shouldn't have damaged the PSU, but if it won't turn on it is possible.

Honestly, I am surprised that the CoolMax unit lasted 8 years, especially with some of its life powering some beefy hardware. You won't know if anything was damaged until you get a new unit, but given the coolmax likely lacks proper protection circuitry, the chances would be higher than a better quality unit.

Looking at the RM750x vs the G3 650w, the RM750x would be my pick for sure. Honestly, you could spend less and still get a good power supply tho.