Sudden drop in network signal strength from desktop to router

[ThumperStrauss]

The download and upload speed on my P7-1459 suddenly dropped to about 6.6Mbps download and 0.8Mbps upload, instead of the usual 55Mbps download and 10Mbps upload. I am not sure what caused the change. The desktop has not moved, nor has the router. No new software was installed, although I did vaccum away the dust from the inside computer case, not touching the motherboard.

I did the same speed test from my Samsung S8 on the same WiFi network and the same physical location. The phone gives the usual higher speed. So, as far as I can tell, the issue is not the Nighthawk R7000 router on a 2. GHz 802.11n protocol.

DIAGNOSTICS

The Windows Network Diagnostic lists the signal strength at -74db in connecting to a 2.4 GHz 802.11n connection. But My Samsung S8 from the same physical location lists the signal strength at -50dBm.

SPECS
Description: Ralink RT5390R 802.11bgn Wi-Fi Adapter
Driver version: 5.0.57.0

HP INFO

Product number: MXX23912BG

WHAT I TRIED

1. Used Windows Network Diagnostics and reset the Network Apater. No improvement.
2. Restarted the  Nighthawk R7000 router. No improvement.
3. I downloaded the Ralink driver updates from HP from[edit]See specs below. No improvement.
4. Ran the HP PC Hardware Diagnostic . WiFi test PASSED.

[Paul_Tikkanen · Accepted solution]

Hi:

The only suggestion I can offer would be to open up the PC and make sure that you did not dislodge the antenna cable(s) from the wifi card when you vacuumed out the PC.

The antenna cables are thin and delicate and it doesn't take much to knock one loose.

Blowing or sucking air from a vacuum cleaner or a can of compressed air could be enough to cause that to happen.

The wifi card is lying flat on the motherboard and it you can see a picture of it on your PC's specs page.

You can see the gold contacts on each side of the top of the wifi card, where the cables snap onto.

https://support.hp.com/ca-en/document/c03520500

The parts list indicates there should be a single antenna cable attached to the card.

http://partsurfer.hp.com/Search.aspx?searchText=H3Y57AA

[ThumperStrauss]

Thank you. You were correct. The antenna had come loose. After placing it in what I know realize was the the empty screw hole, it had no effect. I realize that I should have placed it in the tiny round hole next to the #1 side. 

Funny story, I tried placing it in the tiny hole when the computer was turned on (so that I could see the effect right away), but lost control of the wire and it touched the a chip on the motherboard, which caused the computer to immediately turn off. I turned on and tried again with the same result (didn't learn my lesson). When I tried to turn the computer on, I got the yellow lights (and beeps) flashing five times at the top front of the tower. This signifies a problem with the RAM or motherboard. After making sure that the RAM was in and trying each RAM one at a time to rule out faulty RAM, it appears the motherboard has failed. Hope anyone reading this learns from my experience. I guess I was due for a new computer anyhow.

[Paul_Tikkanen]

You're very welcome.

Sorry that you shorted out the motherboard.

It definitely is not easy working with those tiny antenna wires.

I always shut down and unplug the PC when working inside it.

I even press the power button after I unplug the PC to drain any residual power from the motherboard.