Question New system POSTed out of the case. Now it won’t inside the case. Help!

[21Jumper]

Hey guys,

I just created a new system (parts list below) and I was diligent enough to test everything out of the case. It POSTed fine and recognized all the RAM and the CPU.

After I put it in the case though, now it won’t. Everything turns on including all the RGB but no signal seems to be coming out of the HDMI.

The only difference was that I used extension cable kits for the 24-pin, CPU and PCI-E power. But I’ve since taken those out in the process of elimination and plugged the original cables in, but still getting the same problem.

Here’s everything else I’ve tried:

- plugging the GPU in a different slot
- used one of the Display Ports on the GPU (in both the original and the other slot I tried)
- clear CMOS
- re-seeded all cables and RAM
- taking out one stick of RAM
- used a different GPU (my old GTX 660 from the system I’m replacing)

I think that’s it. I wouldn’t be going out of my mind if it hadn’t posted earlier but since it did, I just can’t think of what else I may have done. Only thing I haven’t done is remove and re-seed the CPU but that’s just because I don’t have any thermal paste on hand right now.

Thanks in advance!

[PCPartPicker Part List](https://pcpartpicker.com/list/zKN7Cz)

Type|Item|Price
:----|:----|:----
**CPU** | [AMD Ryzen 7 2700X 3.7 GHz 8-Core Processor](https://pcpartpicker.com/product/bddxFT/amd-ryzen-7-2700x-37ghz-8-core-processor-yd270xbgafbox) | $229.99 @ Newegg
**Motherboard** | [Asus ROG STRIX B450-F GAMING ATX AM4 Motherboard](https://pcpartpicker.com/product/XQgzK8/asus-rog-strix-b450-f-gaming-atx-am4-motherboard-strix-b450-f-gaming) | $119.99 @ Newegg
**Memory** | [OLOy WarHawk RGB 16 GB (2 x 8 GB) DDR4-3200 CL16 Memory](https://pcpartpicker.com/product/tRsnTW/oloy-warhawk-rgb-16-gb-2-x-8-gb-ddr4-3200-memory-md4u083216beda) | $57.99 @ Newegg
**Video Card** | [ASRock Radeon RX 5500 XT 8 GB Phantom Gaming D OC Video Card](https://pcpartpicker.com/product/H9tKHx/asrock-radeon-rx-5500-xt-8-gb-phantom-gaming-d-oc-video-card-rx5500xt-pgd-8go) | $368.00 @ Amazon
**Case** | [Phanteks Eclipse P300A Mesh ATX Mid Tower Case](https://pcpartpicker.com/product/crqBD3/phanteks-eclipse-p300a-mesh-atx-mid-tower-case-ph-ec300atg_bk01) | $49.99 @ Newegg
**Case Fan** | [In Win Sirius Loop ASL 50 CFM 120 mm Fans 3-Pack](https://pcpartpicker.com/product/NWWfrH/in-win-sirius-loop-asl120-50-cfm-120-mm-fans-3-pack-asl120fan-3pk) | $29.00
| *Prices include shipping, taxes, rebates, and discounts* |
| Total (before mail-in rebates) | $864.96
| Mail-in rebates | -$10.00
| **Total** | **$854.96**
| Generated by [PCPartPicker](https://pcpartpicker.com) 2020-11-29 02:59 EST-0500 |

 

[In2Photos]

Check the case standoffs for the motherboard. Make sure they are only in the spots you need for your mobo and remove any others that could be contacting the mobo.

 

[21Jumper]

Check the case standoffs for the motherboard. Make sure they are only in the spots you need for your mobo and remove any others that could be contacting the mobo.

Ok I can try that. What effect would those have though? For future reference.

 

[In2Photos]

Ok I can try that. What effect would those have though? For future reference.

If there is a standoff contacting an exposed part of the mobo it can cause a short which could lead to no post or even a failure of the mobo or other components.

 

[7beauties]

Hey guys,

I just created a new system (parts list below) and I was diligent enough to test everything out of the case. It POSTed fine and recognized all the RAM and the CPU.

After I put it in the case though, now it won’t. Everything turns on including all the RGB but no signal seems to be coming out of the HDMI.

The only difference was that I used extension cable kits for the 24-pin, CPU and PCI-E power. But I’ve since taken those out in the process of elimination and plugged the original cables in, but still getting the same problem.

Here’s everything else I’ve tried:

- plugging the GPU in a different slot
- used one of the Display Ports on the GPU (in both the original and the other slot I tried)
- clear CMOS
- re-seeded all cables and RAM
- taking out one stick of RAM
- used a different GPU (my old GTX 660 from the system I’m replacing)

I think that’s it. I wouldn’t be going out of my mind if it hadn’t posted earlier but since it did, I just can’t think of what else I may have done. Only thing I haven’t done is remove and re-seed the CPU but that’s just because I don’t have any thermal paste on hand right now.

Thanks in advance!

[PCPartPicker Part List](https://pcpartpicker.com/list/zKN7Cz)

Type|Item|Price
:----|:----|:----
**CPU** | [AMD Ryzen 7 2700X 3.7 GHz 8-Core Processor](https://pcpartpicker.com/product/bddxFT/amd-ryzen-7-2700x-37ghz-8-core-processor-yd270xbgafbox) | $229.99 @ Newegg
**Motherboard** | [Asus ROG STRIX B450-F GAMING ATX AM4 Motherboard](https://pcpartpicker.com/product/XQgzK8/asus-rog-strix-b450-f-gaming-atx-am4-motherboard-strix-b450-f-gaming) | $119.99 @ Newegg
**Memory** | [OLOy WarHawk RGB 16 GB (2 x 8 GB) DDR4-3200 CL16 Memory](https://pcpartpicker.com/product/tRsnTW/oloy-warhawk-rgb-16-gb-2-x-8-gb-ddr4-3200-memory-md4u083216beda) | $57.99 @ Newegg
**Video Card** | [ASRock Radeon RX 5500 XT 8 GB Phantom Gaming D OC Video Card](https://pcpartpicker.com/product/H9tKHx/asrock-radeon-rx-5500-xt-8-gb-phantom-gaming-d-oc-video-card-rx5500xt-pgd-8go) | $368.00 @ Amazon
**Case** | [Phanteks Eclipse P300A Mesh ATX Mid Tower Case](https://pcpartpicker.com/product/crqBD3/phanteks-eclipse-p300a-mesh-atx-mid-tower-case-ph-ec300atg_bk01) | $49.99 @ Newegg
**Case Fan** | [In Win Sirius Loop ASL 50 CFM 120 mm Fans 3-Pack](https://pcpartpicker.com/product/NWWfrH/in-win-sirius-loop-asl120-50-cfm-120-mm-fans-3-pack-asl120fan-3pk) | $29.00
| *Prices include shipping, taxes, rebates, and discounts* |
| Total (before mail-in rebates) | $864.96
| Mail-in rebates | -$10.00
| **Total** | **$854.96**
| Generated by [PCPartPicker](https://pcpartpicker.com) 2020-11-29 02:59 EST-0500 |

Pardon me, but why did you test components before installation? All CPUs today require a 4-6 pin power tap close by. Is that cable attached? Check every part of the start/off header of your motherboard. Trace the green/white wire from your case's power switch; the plug is labeled 'power' or 'pwr' and use your motherboard's manual to know where this connector goes to. That could be your problem. Please let us know how you resolve this. Thank you.

 

[Steltek]

Pardon me, but why did you test components before installation?

Experienced system builders learn this trick fairly quickly as parts that are DOA out of the box aren't uncommon (especially motherboards, video cards and memory modules due to poor quality control by manufacturers).

It is always a good idea to test your components so you know everything is in working order before you waste time mounting them in the case, only to have to start tearing things out to troubleshoot. With some cases, this is a major undertaking depending upon case size and component placement. It is far easier to test outside the case where you can quickly move and swap components.

The easiest and quickest way to do it is to place the motherboard on a non-conductive surface such as a cardboard box, mount the CPU/cooler, add a memory module, and the video card (if the system doesn't have integrated graphics). It also doesn't hurt to add any NVMe drives (if only to ensure they are detected by the BIOS). Carefully plug in the PSU cables, turn on the PSU switch (if it has one) and post the system with a screwdriver to short the motherboard power switch pins (or, if the motherboard has one, use its onboard power switch). If everything works, great, proceed with installation. If it doesn't, start pulling and swapping parts until you figure out what is bad.

In OP's case, they knew going in they had good components because they tested before installation. Because pre-installation testing was done, in this case the immediate logical first step would be to check for a case mounting issue between the motherboard and case (usually resulting from an improperly placed case standoff creating an electrical short or ground loop). The OP didn't post back, so I presume that @In2Photos ' suggestion likely solved the problem.

 

[7beauties]

Steltek, you certainly know a lot more than I do. You might be right about a stand-off creating a ground or short problem. Please let us know how you resolve this so that we'll know. I know that you'll resolve this. Thank you.