PC boots but no signal on screen

kosta.kritikos01

Prominent
Sep 29, 2017
3
0
510
Hi,
I had a few spare parts lying around the house and decided to build a new/spare PC.
My main rig is perfectly fine and I just have no idea why this one isn't working. The PC boots and the fans kick up but there is no signal on the monitor. I have tried absolutely everything to fix it, including...

Resitting the CPU
Reapplying thermal paste (x3)
Using a new CPU fan
Purchasing a new CMOS battery
Installing new RAM and trying different configurations
Rebuilt the entire PC 3 times in 3 different cases and once on the mobo box
Clearing the CMOS (Bios)
Using a new GPU
Using a new HDD
Using a new PSU

I have come to the conclusion that it is either a faulty Mobo or a faulty CPU. I somewhat tested the Mobo by taking out the GPU and seeing if the beep codes work (which they do). The system seems completely fine with no strange noises and beeps but for some reason wont display signal... could it be a dead CPU or a faulty MOBO?

I am considering buying a new MOBO for the lols to see if it works but could a posting system signal a dead mobo? I assumed that if the system boots then it is probably a faulty mobo but that doesn't make sense since the whole system still boots and it cant be a faulty cpu because then it would turn on at all.. right? I am convinced it is either the CPU or Mobo but don't know which one it is.
What else can I try? The CPU and Mobo were working before I put the PC away but now it doesn't work (parts were on the shelf for 6months)


Specs:
AMD FX 6300
Asrock 970 Extreme 3 r2.0 AM3+
AMD Radeon R7 260x
Antec True Power Classic 650w
Seagate Barracuda 1tb HDD and 2tb HDD
Cooler master K380, and 2 other Generic PC cases
12GB Corsair Vengeance DDR3 RAM (4GB 1666MHz + 8GB 1666MHz)


Thanks in advance!
 

kosta.kritikos01

Prominent
Sep 29, 2017
3
0
510


I tried that, used a different GPU in the system (r9 390x) and a different PSU but the problem still occured.
l even tried the 260x in my new system and it worked perfectly fine.
 

kosta.kritikos01

Prominent
Sep 29, 2017
3
0
510


Yeh, everything Is plugged in properly and I have tried redoing all the cables a few times.
Most motherboards made after 2008 would be able to supply the required 75w but that isn't an issue anymore since all mobos can supply it. Every PCIE express 16x slot should support it so I don't think it is a power issue like mdd was saying (my 260x requires a single 8pin connector)