PC Turns on and then off repeatedly.

[MyNameJeff123]

Hello,
Started building a pc for my sister yesterday with the following specs:

CPU: i5 7400 [re-used from old build]
MOBO: Msi z170a [re-used from old build]
RAM: 4x4gb ddr4 [re-used from old build]
GPU: Gigabyte GTX 1650
1x Sata SSD
1x Sata HDD
PSU: Corsair CV550

The parts that are being re-used all worked before and even worked when i tested this build outside the case. Put it all in the case and suddenly the pc wouldnt turn on anymore. I turn it on, all the fans spin, the mobo lights up, not a second later it shuts down again and repeats that loop after 1-2 seconds.

Things i've tried:
Tested with my own PSU -> Same problem.
Swapped RAM around to all slots -> same problem, also occurs without any RAM installed.
Jumped JBAT1 for a cmos reset -> didnt work.
Pulled cmos battery out for a good 30 minutes -> didnt work
Checked for bent pins -> Pins look fine.
Checked for burned VRM's -> VRM's look normal
Took everything out and built it up again outside the case -> still the same problem.

Whats interesting is that when you pull the CPU 8 pin and leave the 24pin it actually does start up, as in, the fans stay on and the mobo stays lit up.

Does anyone know whats going on and how to fix it? I dont have another intel cpu or lga1511 board laying around to test cpu or board.

Thanks in advance.

[Enzo1001]

Maybe try to boot with an other ssd?

[MyNameJeff123]

2 minutes ago, Enzo1001 said:

Maybe try to boot with an other ssd?

It doesnt get anywhere near booting. Like i said, this happens with and without: RAM, GPU, SSD, HDD

[Enzo1001]

What kind off parts are new?

 

[MyNameJeff123]

1 minute ago, Enzo1001 said:

What kind off parts are new?

 

Man did you even read my post? It says right there

[Enzo1001]

4 minutes ago, MyNameJeff123 said:

Man did you even read my post? It says right there

Sry but your not the only one right now who im helping solving a problem, either way, what do you mean by this?

Quote

Whats interesting is that when you pull the CPU 8 pin and leave the 24pin it actually does start up, as in, the fans stay on and the mobo stays lit up.
 

 

[MyNameJeff123]

Just now, Enzo1001 said:

Sry but your not the only one right now who im helping solving a problem, either way, what do you mean by this?

 

What i mean by that is that im not experiencing the problem described. but obviously i cant get very far without cpu power.

[Enzo1001]

Oh ok and this?

Quote

Tested with my own PSU -> Same problem.

 

[MyNameJeff123]

1 minute ago, Enzo1001 said:

Oh ok and this?

 

Confirming that the powersupply is not broken. Both the new one and my own one give the same problem