DreamPC2006 died again probably because of usb port/plug misalignment on pins.

Well you are half right, I design computer based security systems so I am constantly working with the tech but I still enjoy setting up elaborate systems at home also.

Perhaps after a large number of years I will get bored.

That's probably latchup on the Southbridge, from the mis-connected header. The Southbridge is probably ruined. The one under the aluminum heatsink next to the three USB2 headers.

I have a floor lamp with an adjustable arm on it, that I use for lighting the PC when working inside. Makes a big difference. Plenty of light, so I can move wiring safely.

When fitting USB headers, turn off all power. You can do that by switching the PC off at the back. Or, unplug the PC. That's to ensure there is no +5VSB inside the chassis (which also powers the USB header). Then fit the header. Fitting one of those headers with the power on, is asking for trouble.

And like it says in the motherboard manuals, if the computer has both IEEE1394 headers and USB2 headers, they have the same pin pattern. Don't install the USB2 header on a IEEE1394 2x5. Both have the keying pin in the same place.

Paul

Well this explains it quite nicely it seems.

I suspect the following happened.

Since the PC is not grounded as so many in this world, the 110 volts which is on the ground wire through the PC entered into the P+7 P+6 lines... probably going through the entire PC and back into the audio system.

I'd be lucky if everything else still works.

A nice example why ground is dangerous to equipment.

Also why 110 volts must be on case and not dumped back to eletricity grid is beyond me.

Probably another stupid design.

Bye, Skybuck.

Blame: PC designers.

There fixed that for ya.

Quite strange how my Sharp TV still works after 20 years, but these latest usb port/audio crap shit doesnt. Bleh !

At least I dont attach so much stuff to my Sharp TV.

Conclusion: attaching stuff is spark prone.

Bye, Skybuck.

Why you need a ground in electrical wiring: Unfortunately, the life you save (by proper grounding) will probably be yours.

Well, if you're correct, there's a simple solution. Purchase a surplus 25kw isolation transformer (two phase) and use it to isolate your entire apartment from both the power grid and earth ground. (A fork lift may be required for installation). Since there will be no voltage between your lines and ground, it will be safe for you to break off all the grounding pins on all your equipment. I use a smaller version of the same isolation transformer idea on my lab bench when working on switching power supplies, so that grounding the oscilloscope doesn't create a smoking wire. However, you will need to be rigorous and diligent with your power line isolation efforts. If one phase accidentally hits earth ground, anything that gets between any of the other phases and earth ground will be electrocuted.

Here's what may be a sample of such an installation:

R.I.P. in advance.

Only if you did not unplug it first.

Alright, you've trapped me again,

It is there because you did not ground it. There's circuitry in your PSU that essentially forms a high resistance path from line to Ground(=your case). As your ground pin(and case) are not connected, it will freely float to some voltage between the two phases.

You have something(_very_ roughly) like the following. L | | |both R very large(leakage from capacitors etc...) | | *---*---< you can touch this point, | | but it hurts. It's the case and | | the local, unconnected ground pin. | | --- C_case | | --- | | GND

Do not expect weird behaviour, if you use equipment in different ways than what it was designed for. It is like pulling slime from your nose with a power drill.

Even if you tried to 'dump' the 110V back to the grid you could not do it without ground connection. The wall plug fits both ways, so line and neutral wire can be swapped at random. You can therefore not connect the case to the neutral pin that the PSU sees, as that may in fact be the live one. You'd get electrocuted as soon as you touch it. Even if the wall plugs were keyed, neutral may not be at ground potential, as it carries return current and will drift around a bit. The ground bracket on the plug will _always_ fit to the ground contacts, so that is the 'only' sane reference point for your case. Yes, certain consumer equipment has just two pin plugs, but that stuff is designed to work that way.

En el artículo , Johann Klammer escribió:

Nice analogy. :)