Question How to remove the pre-installed PSU from an MSI MAG M100A case ?

Jul 5, 2025
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So i bought a Gigabyte RTX 5070 SFF GPU and a Corsair RM850x 850w PSU and was planning on replacing my existing GPU and PSU with those. However, i wasn't able to remove the PSU and I don't know how to.
So I was wondering if you all could help me with that.
 
Welcome to the forums, newcomer!

Disconnect all connections made from the PSU to your devices/components. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:

We already know your 2 new parts are the GPU and PSU listed in your initial post.
 
MSI MAG M100A, PSU IS BUILT IN 600 WATT, RX 7700XT, I7 12700F, NVME GEN 3 MLD M300, GIGABYTE H610M H V2 DDR4 1700, RAMPAGE OCTAGON C50, GSKILL F4 32GB (2x16) 3600MHz
 
So i bought an rtx 5070 SFF GIGABYTE version and a corsair rm850x 850 WATT psu and was planning on replacing my old gpu and psu with that. However i wasn't able to take off the psu and i don't know how to and was wondering if you all could help me with that.
Which specific part are you having a problem with? Refer to page 15 of the manual:

https://download-2.msi.com/archive/mnu_exe/case/MAGFORGEM100R_M100A.pdf

Basically the power supply is held in by the four screws in the back. You unscrew it and slide it out. If the old power supply is not modular you will have to disconnect all of the cables from the motherboard and other peripherals. Make notes and take pictures with your phone if you are not familiar with where all of the old cables are connected. Note when installing the new power supply the fan faces down.

Please update us on which specific part is giving you a problem.
 
Is the hard drive cage blocking your ability to pull the power supply forward and move it out of the case? Did you try removing the cage to provide more room to work? Are the cables connected to the power supply too short and preventing you from pulling it out?
hard drive cage might be the problem but i dont know how to remove it and the screws are circular and small which makes it even more difficult and i dont even know if they are removable or not. I believe the screws in the back arent screws they are just rivets.