New build doesn't respond </3

[BurnedPriest]

So yesterday I built a new system for a friend. After everything was done, I plugged it in and nothing. The mobo has LED's which they didn't turn on, neither the case/cooler fans.

I tried the paperclip thingy on the PSU to verify it's functioning and indeed it turned on. So it's kinda obvious to me what is the issue, I just want to get some other opinions before I go through the time consuming process of taking apart the pc again to RMA the motherboard. 
Am I missing something? The 24-pin and 8-pin are connected to the mobo, so even wtih that alone it should power up, right?

 

Specs:

CPU: i5 8400
GPU: GTX 1070
MOTHERBOARD: Z370 MSI GAMING PLUS
RAM: 8GB CRUCIAL DDR4 2400MHZ

PSU: THERMALTAKE SMART SE 630W 80+

CASE: PHANTEKS P400

[astrosheen]

13 minutes ago, BurnedPriest said:

So yesterday I built a new system for a friend. After everything was done, I plugged it in and nothing. The mobo has LED's which they didn't turn on, neither the case/cooler fans.

I tried the paperclip thingy on the PSU to verify it's functioning and indeed it turned on. So it's kinda obvious to me what is the issue, I just want to get some other opinions before I go through the time consuming process of taking apart the pc again to RMA the motherboard. 
Am I missing something? The 24-pin and 8-pin are connected to the mobo, so even wtih that alone it should power up, right?

 

Specs:

CPU: i5 8400
GPU: GTX 1070
MOTHERBOARD: Z370 MSI GAMING PLUS
RAM: 8GB CRUCIAL DDR4 2400MHZ

PSU: THERMALTAKE SMART SE 630W 80+

CASE: PHANTEKS P400

build outside the case with just motherboard and 1 sick of RAM. If it works add stuff till it doent

[WereCat]

Remove the GPU, try to boot just with the iGPU and single stick of RAM (try in multiple slots)

[wONKEyeYEs]

Turn on the PSU power switch.

[BurnedPriest]

2 hours ago, astrosheen said:

build outside the case with just motherboard and 1 sick of RAM. If it works add stuff till it doent

 

2 hours ago, WereCat said:

Remove the GPU, try to boot just with the iGPU and single stick of RAM (try in multiple slots)

 

 

I put the mobo out, only with the cpu and ram on and nothing..

 

1 hour ago, wONKEyeYEs said:

Turn on the PSU power switch.

 

  That sounds too scary for me, I might take it to a tech guy to do that.

 

[Tobias K.]

Please ensure, that you have plugged the panel connectors correct.

 

You could also try to bridge the power pins from the panel connectors.

[BurnedPriest]

56 minutes ago, Tobias K. said:

Please ensure, that you have plugged the panel connectors correct.

 

You could also try to bridge the power pins from the panel connectors.

I took it apart now, testing is over for me, I'm just gonna send it back to the seller. I did try with no panel connectors plugged but nothing happened, the LED's on the board should light even so.