Mac Mini WiFi Issues

[F.Garvin]

Hello - I purchased a 2014 Mac Mini. I took it apart a few days ago to install a SSD. Everything seemed to go well. I installed the OS via WiFi and then upgraded to Sierra the same day. The WiFi worked fine the first couple days, but then today I went to put some files on the external drive I have connected to it, when I came back the WiFi wasn't working and it was turned off, which it was not when I left it.

I went to turn on, but it tells me it cannot connect and perhaps my password is wrong. I ran the diagnostic, but that offered some very simple solutions like making sure it's on and I don't know how to read the diagnostic report the troubleshooter generated. I tried rebooting the Mini and the router, but neither worked. I don't think the card is working because it only sees the network I was using before, while my Windows notebook can see 10+ other networks. Is there anything else I can try to fix this? My Mini is under warranty, but the Apple store is far and I'm sure they'll frown on me taking it apart. Thanks for any help.
[doublepost=1500197322][/doublepost]It seems I should have done some reading before posting, cause I have an 8TB external drive hooked to the Mini. Once I unmounted and unplugged it, WiFi started working. Is there some way I can use the drive if I set it far enough away? Thanks again.

 

[Fishrrman]

Electrical interference from the USB3 cable is interfering with the wifi.
Known problem...

 

[Partron22]

Get a a better cable. IDK if wrapping current cable in aluminum foil will work, but it might.

 

[F.Garvin]

Get a a better cable.

Thanks for the replies. Is there a known better cable? Thanks again.

 

[Partron22]

The cable that came with my Sabrent drive caddy caused problems.
A generic Amazon USB3 cable worked fine. -> They may have switched suppliers by now.

 

[F.Garvin]

Thanks Partron. I just got off the phone with Apple support and they were saying it was electrical interference coming from the hard drive, not the cable. They asked if I moved the drive further away, did it help, which it seemed to, though it was slight and may have been within in the margin of error. I'm wondering if get a new cable, will it help? Thanks again.

 

[Partron22]

As Fishrrman said cables are a known problem. Drive could do it too, but I've not seen that.
Try some aluminum foil between the devices. Likely no need for a full Faraday cage. If it's the drive housing, covering that with foil should make a difference.

 

[Fishrrman]

The best cable to use is an -ethernet- cable to the Mini, if you can swing it...

 

[F.Garvin]

I bought another cable. It's a 10'er, so if nothing else, hopefully I can move it farther away and that'll help. Thanks for the replies.