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General discussion

No signal after installing new graphics card

Mar 13, 2017 1:26AM PDT

Hi all
I'm in need of some help. My brothers graphics card was faulty, and so I replaced it with an old Radeon HD 7870 I had laying around which I know still works because I only took it out a few months ago after upgrading to a GTX 1070.

After installing I found that there was no signal to the monitor. I've tried a number of things, resetting CMOS, testing the two sticks of 8GB RAM, tried the 2nd PCI-E slot on the motherboard, I don't think the 750W PSU is the problem.

The only way I can get a signal is when I removed the GFX card and use the motherboards integrated graphics. I would presume that in order to get a signal I'd need to somehow get into the BIOS and disable integrated graphics and prioritise the PCI-E slot, however, how do I do that if I can't even get a signal in order to get into BIOS. I notice that even if I'm running integrated graphics with the GFX card out, I can get into the BIOS and change those settings, but as soon as I installed the GFX card again, those settings are changed back to auto?
If anyone could shed some light it would be much appreciated.

Thank you.

Discussion is locked

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The most common issue is
Mar 13, 2017 5:05AM PDT

The installer forgets to run power to the 7870.

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Power's not the issue
Mar 14, 2017 2:47AM PDT

The 7870 definitely has power. The fans are spinning, it's connected to a 750W PSU.

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Then it is time
Mar 14, 2017 8:02AM PDT

To test this card in another PC. May be tough for some to accomplish.

If the card works in another PC then the news is grim. The motherboard is suspect.

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Possibly
Mar 14, 2017 8:09AM PDT

Funny thing is if i plug in the broken graphics card it still boots, it's just the screen has green lines through it. Could this also be caused by a faulty motherboard?

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Maybe.
Mar 14, 2017 8:21AM PDT

That's why we test in another PC.

As to the 750W PSU. There are QUAD RAIL models that are junk. This is usually how folk learn that lesson.

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Your motherboard model supports the old graphic?
Mar 16, 2017 3:01AM PDT

What is your motherboard model? And did you checked that if it supports your old Radeon HD 7870 graphic card?

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New hardware
Mar 20, 2017 3:48AM PDT

Ok. So i went out and board a ASUS Z270-AR motherboard, this in turn also required new RAM, as the mobo uses DDR4 rather than DDR3, so i bought 2x4GB sticks of Kingston HyperX RAM. With no graphics card installed, and trying to use integrated graphics which run via a HMDI cable rather than VGI, I still get no signal on the monitor.

I've tried most things I can think of;
- Remove CMOS battery and short the CMOS jumper.
- held down the power button for 1min without the power cable in.
- checked all cables to the motherboard etc.
- tried running powering the system with only the CPU, mobo, power supply, ram and fans.
- tried the memory sticks one at the time in each of the 4 DIMM slots.
- checked CPU slot for any bent pins.

The only two things I can really replace now are the CPU and PSU. I'm at a loss and am basically just building another PC. Any help would be much appreciated. Unfortunately I don't have a mobo speaker so i can't test for beeps.