Question Why does my Tower not start until I switch from 115v to 230v and then back again to 115v before I hit the power button?

WhatKnots

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Jun 26, 2021
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About 2 or 3 months ago, I started having a problem starting my computer. At first I thought it was caused by power outages at my apartment. Regardless of the cause, one morning I could not start my PC. I had checked cables, wall plates, circuit breaker, etc. I opened the PC and checked internal connections. I found nothing of concern. Put it all back together. Reconnected cables and verified the 115v switch. Still could not start the computer even after changing outlets on the wall and the surge protector which had not problem getting power to other devices connected to it. I then went back to the red switch with the 115v marking on it. I changed it to 230v and immediately right back to 115v. TADA~!!

So WTH?

I figured that's weird and was happy to believe it won't happen again. But...nooo. For some unknown reason and without any sense of apparent logic, it happens again and again. Why?
While I have an old PC, it runs great for the most part. It runs quiet. I don't smell any unusual fumes. Is there anything going on short of the apparent possibility I may have to replace the power supply? What keeps me from thinking it is the power supply is the fact the problem is only occurring once in a while and only at startup.

Thanks

Windows 10 Professional (x64) Version 2009
3.40 gigahertz AMD Phenom II X4 965
ASUSTeK Computer INC. M4A87TD/USB3 Rev 1.xx
Bus Clock: 200 megahertz
UEFI: American Megatrends Inc. 1102 12/09/2010
SPCC Solid State Disk (512.11 GB) -- drive 0 Healthy
WDC WD1002FAEX-00Z3A0 [Hard drive] (1000.20 GB) Healthy
AMD Radeon HD 5670 [Display adapter]
AMD High Definition Audio Device
High Definition Audio Device
NOTE: above is everthing but the kitchen sink AND the Power Supply but the PS is a 500W(10 yr old)
 
I appreciate your reply. But if I search for Power Supplies on the internet, I always see 500W power supplies returned on the search. Am I missing something in your explanation?
Thanks
 
There are 500W PSUs out there. Mine is a 550W, my previous was a 450W. They do exist. NONE of them have that little red switch in the back. Any real PSU out now, with some exceptions for EU only PSUs, now has universal input and can correct for the input voltage automatically. It's a part of the 80+ cert program. By having that switch I know this is a PSU based on an ANCIENT design and as such shouldn't be used anymore.

https://www.newegg.com/seasonic-s12iii-bronze-series-ssr-500gb3-500w/p/N82E16817151226
This is a 500W PSU. You are good to use this one if you want.

This is not a 500W PSU. It has only 400W on the 12V rails, and even then I wouldn't trust it. This is a fire waiting to happen.
 
This is not only a low-quality PSU but one that's having obvious problems; you should never be having to play with a voltage switch like this. I would not use this PSU at all at this point, even to just surf the web, if you value the equipment it's powering. As 47 notes, that it even has such a switch in 2021 is troubling.
 
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