[SOLVED] CPU or Motherboard Dead?

Feb 24, 2020
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I bought a Gaming Computer from a friend that broke on him and I have been trying to fix. When you turn it on it will light up fans will go and only start for a second then shut down. Sometimes it will start up but if it has been turned off for a few hours it goes back to not starting again. I've swapped out the RAM, SSD, Graphics Card and Power Supply to test and have had the same issue. I brought it to a PC repair shop and they told me the issue was the Motherboard. I got a used motherboard online and rebuilt the machine. Got the same exact thing with it only starting for a second then turning off. Could it be my CPU at this point?

CPU-i7-4790K
Motherboard - Sabertooth Z97 Mark 1 or Gigabyte Z97X UD5H
PSU- AX860
Graphics card- Geforce GTX 1080 PCI express 3.0
SSD- 960 EVO Sata 6 Gb/S
Ram- 2X Vengeance Pro DDR3 2X4
CPU cooler- Bequiet Rock Pro 4
 
Solution
The paper clip test really doesn't test the PSU. It just allows it to power on.

If I were a betting man, I would say the PSU is the issue. You are describing a power issue in many ways.

geckovic02

Reputable
Jan 21, 2019
131
22
4,615
I bought a Gaming Computer from a friend that broke on him and I have been trying to fix. When you turn it on it will light up fans will go and only start for a second then shut down. Sometimes it will start up but if it has been turned off for a few hours it goes back to not starting again. I've swapped out the RAM, SSD, Graphics Card and Power Supply to test and have had the same issue. I brought it to a PC repair shop and they told me the issue was the Motherboard. I got a used motherboard online and rebuilt the machine. Got the same exact thing with it only starting for a second then turning off. Could it be my CPU at this point?

CPU-i7-4790K
Motherboard - Sabertooth Z97 Mark 1 or Gigabyte Z97X UD5H
PSU- AX860
Graphics card- Geforce GTX 1080 PCI express 3.0
SSD- 960 EVO Sata 6 Gb/S
Ram- 2X Vengeance Pro DDR3 2X4
CPU cooler- Bequiet Rock Pro 4

In the worst case you forgot the thermal paste on the cpu
 

geckovic02

Reputable
Jan 21, 2019
131
22
4,615
I only put a dab on it. Do you think I need more? Would that cause it to shut off after just a second?
It's maybe stuck in a bootloop. Take everything off the motherboard and only boot it with the motherboard, cpu + cooler and the psu installed (24pin and cpu power cable). Plug in a vga cable into your mobo if you can, if not listen if you get a beep.

If yes, shut off the system, add the ram and bot again. Do that until you can figure out what componement is doing problems.

If it shuts of again, it will probably be the cpu, as you already changed motherboard and psu?
 
It's maybe stuck in a bootloop. Take everything off the motherboard and only boot it with the motherboard, cpu + cooler and the psu installed (24pin and cpu power cable). Plug in a vga cable into your mobo if you can, if not listen if you get a beep.

If yes, shut off the system, add the ram and bot again. Do that until you can figure out what componement is doing problems.

If it shuts of again, it will probably be the cpu, as you already changed motherboard and psu?
This is the method I would have used before paying a shop.
 
Feb 24, 2020
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It's maybe stuck in a bootloop. Take everything off the motherboard and only boot it with the motherboard, cpu + cooler and the psu installed (24pin and cpu power cable). Plug in a vga cable into your mobo if you can, if not listen if you get a beep.

If yes, shut off the system, add the ram and bot again. Do that until you can figure out what componement is doing problems.

If it shuts of again, it will probably be the cpu, as you already changed motherboard and psu?
Just did what you said and the same issue. Only starts for a second then shuts down. Yeah I just swapped out the Motherboard and PSU and the same issue. My only thought left is the CPU.
 
Feb 24, 2020
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Well I got and installed the new CPU and the same issue. At this point I am completely lost. I just tried swapping out cables even though the PC shop said they did that and the same issue. Totally lost.
 
Feb 24, 2020
14
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Feb 24, 2020
I bought a Gaming Computer from a friend that broke on him and I have been trying to fix. When you turn it on it will light up fans will go and only start for a second then shut down. Sometimes it will start up but if it has been turned off for a few hours it goes back to not starting again. I've swapped out the RAM, SSD, Graphics Card and Power Supply to test and have had the same issue. I brought it to a PC repair shop and they told me the issue was the Motherboard. I got a used motherboard online and rebuilt the machine. Got the same exact thing with it only starting for a second then turning off. Could it be my CPU at this point?

CPU-i7-4790K
Motherboard - Sabertooth Z97 Mark 1 or Gigabyte Z97X UD5H
PSU- AX860
Graphics card- Geforce GTX 1080 PCI express 3.0
SSD- 960 EVO Sata 6 Gb/S
Ram- 2X Vengeance Pro DDR3 2X4
CPU cooler- Bequiet Rock Pro 4

So I purchased a used Gigabyte Motherboard and swapped that out and had the same issue. I then got a used i-7-4790K to swap out. Same exact issue. When I turn on the computer it starts for 1 second then shuts back down. I have tried swapping out all my cables. I have pulled every thing out except the CPU and Motherboard and same issue. My PC shop and my friend both tried different PSUs but had the same issue. I even pulled the board out of the case and place it on cardboard to see if the case was short circuiting it and still had the same issue. I am at a lost at this point. Unless the Motherboard I bought online was bad as well. Thanks for any insight or help.
 
Feb 24, 2020
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So I have done that before and sometimes it turns on. Then when I shut it down for the night the next morning it won't boot again. This morning I tried to boot it again and it wouldn't boot just kept trying. I left my apartment for 4 hours came home and it booted right up. I am totally confused.