Power supply on way out?

**Richardd150** · 25-01-2013, 08:31 AM

Thanks pctek and KarameaDave and linw.
In one of those mid-night aha moments (tested this morning) I've found it's something to do with the recently purchased USB hub. Essentially, hub plugged in any of the rear ports (2.0 or 3.0, makes no diff) and the problem occurs, plug into front 2.0 ports , no prob.
To add to the story with the back ports. If I push the start button with the hub connected, the problem occurs, if then I pull the hub's cable out of the port (with no intermediate steps) the PC proceeds to boot as normal without me doing anything else!!! It's like pushing the start button primes the start up but the presence of the hub connection blocks it, remove the connection and the start up process carries on without having to do anything else. Weird, huh?
I've also tested the "bad" wall socket potential by doing a shorter test run than the marathon I ran last night, using that power point and without the hub connected - no issues except when I connected the hub.
So, I think I've eliminated the dying PSU and "bad" power point "suspects". Investigations are now focussing on potentially dodgy usb hub and or rear USB ports.
Any insights much appreciated, as always!

**dugimodo** · 25-01-2013, 08:50 AM

That's a weird one, is it a powered USB hub and if so does removing the power from it work the same as unplugging it?
The only Idea I have is there is a minor earth loop raising the voltage on the earth slightly. The PC starts up the power supply by earthing a pin (the green wire on the 24 pin plug), maybe if there is some voltage on the earth it doesn't detect properly.

I'd suspect that either the Hub is faulty or the rear USB ports are, difficult to prove though.

**Richardd150** · 25-01-2013, 09:44 AM

It is powered and I'll test your suggestion this evening. Thanks!

It's a seven port hub with 3x 2.0 and 4x 3.0 ports.

**Richardd150** · 25-01-2013, 05:21 PM

Originally Posted by dugimodo

That's a weird one, is it a powered USB hub and if so does removing the power from it work the same as unplugging it?
The only Idea I have is there is a minor earth loop raising the voltage on the earth slightly. The PC starts up the power supply by earthing a pin (the green wire on the 24 pin plug), maybe if there is some voltage on the earth it doesn't detect properly.

I'd suspect that either the Hub is faulty or the rear USB ports are, difficult to prove though.

Thanks for the suggestion!

So, I replicated the problem with the rear 3.0 usb port i.e. powered down, plugged in the hub (including power supply for powered hub) and the problem occurred (i.e. did not power up when I pushed the start button), then simply as the next step I turned the hub off at the wall - Bingo, just like in post #11 ..."the PC proceeds to boot as normal without me doing anything else!!! It's like pushing the start button primes the start up but the presence of the hub connection blocks it, remove the connection and the start up process carries on without having to do anything else.".

I think that's a strong indicator for the issue being with the hub rather than the port as it wasn't the removal of the hub (which continued to be powered by the usb port) connection, but removal of the external power supply to the hub that did the trick. Is that sound reasoning?

**Digby** · 25-01-2013, 07:28 PM

Geez
That would be a worry
I hope it got it fixed.
I was going to suggest that he takes out the fuse in his switch board until he gets a sparky there.

Good lessons for us all - try the pc in a different room on different circuit.

But I wonder if other things were running on that plug ?

**Richardd150** · 25-01-2013, 07:56 PM

Originally Posted by Digby

Geez
That would be a worry
I hope it got it fixed.
I was going to suggest that he takes out the fuse in his switch board until he gets a sparky there.

Good lessons for us all - try the pc in a different room on different circuit.

But I wonder if other things were running on that plug ?

Just the PC (inc monitor), printer and speakers. That's not unusual, is it?
I'm confident it's nothing to do with the house wiring (or surge protector or). I'm more and more confident that it's the usb hub.
Doing some more tests now.

**Richardd150** · 25-01-2013, 08:51 PM

Ladies and gentlemen of the forum, I have something a little embarrassing to share, but in the interest of others learning from my experience I'm willing to show my blushes

I found this little gem of a download that had previously eluded me - "USB 3.0 hub- RENESAS-USB3-Host-Driver- update (for those who have RENESAS host chipset on their motherboards with compatible issues to run mbeat USB3.0 hub )". I vaguely recalled a message popping up in the past that my hub would perform better if connected to such a "3.0" hub. However, the hub appeared to be working.

Downloaded and applied, my PC happily powers down, powers up and reboots without a hitch. I'm still mystified as to why it appeared to be related to whether the hub was externally powered or not.

Thank you one and all.