Locking the BIOS?

[petersmart]

Re: Locking the BIOS?

Phew ..... There are so many electrical things that could go wrong by and or with not using standoffs, namely a solid reliable ground path for the mb, that I simply can't begin to fathom how the mb might still be running. Never mind permanently damaged.

Go HERE and get that mb some standoffs and screws. And after they're installed pray to the Deity of choice that you haven't permanently damaged the mb or another component or components that resides on the mb.

Wrong. Just wrong ............ The board has probably been arcing ............ against the I/O backplate looking for a ground. Then ZAP ............ It discharges .............

No it IS connected and earthed via the screws going through the cardboard to the backplate - the m/b isn't just floating which would make it impossible to connect anything to it - but I will connect standoffs just to be really safe.

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[- wardog -]

Re: Locking the BIOS?

No it IS connected and earthed via the screws going through the cardboard to the backplate - the m/b isn't just floating which would make it impossible to connect anything to it - but I will connect standoffs just to be really safe.
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Turning the screws tight enough to make a reliable ground while using a compressible material such as cardboard/paperboard won't, IMHO, provide a lasting and permanent path for ground. I'm of the opinion what you're experiencing bears this out. Hence the reason all mb's have a highly conductive ring that surrounds every mounting hole that the screw tightens to when threaded into each standoff.

When we initially build them up, out of the case and on a box, there isn't anything that can electrically make contact with any of the electrical pathways of the mb. Electricity follows the path provided.

And it's assumed that afterwards, when it installed in the case using standoffs, that all electrical paths are tight and secure. Hence why we go back over the screws a second(or third) time making damn sure we didn't miss one. Electricity follows the path provided.

Give electricity a chance, such as you have here, to take a path with lessor resistance and you create an intermittent short that will arc. Creating damaging discharges.

[petersmart]

Re: Locking the BIOS?

Turning the screws tight enough to make a reliable ground while using a compressible material such as cardboard/paperboard won't, IMHO, provide a lasting and permanent path for ground. I'm of the opinion what you're experiencing bears this out. Hence the reason all mb's have a highly conductive ring that surrounds every mounting hole that the screw tightens to when threaded into each standoff.

When we initially build them up, out of the case and on a box, there isn't anything that can electrically make contact with any of the electrical pathways of the mb. Electricity follows the path provided.

And it's assumed that afterwards, when it installed in the case using standoffs, that all electrical paths are tight and secure. Hence why we go back over the screws a second(or third) time making damn sure we didn't miss one. Electricity follows the path provided.

Give electricity a chance, such as you have here, to take a path with lessor resistance and you create an intermittent short that will arc. Creating damaging discharges.

I believe you could be right as this morning when I turned a light on in the kitchen the PC started up - I have it set up to turn on when I turn on the main power supply to it or press a key on the keyboard.

MMM - time to install proper standoffs.

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[- wardog -]

Re: Locking the BIOS?

I believe you could be right as this morning when I turned a light on in the kitchen the PC started up - I have it set up to turn on when I turn on the main power supply to it or press a key on the keyboard.

MMM - time to install proper standoffs.

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Get however many standoffs as there are mounting holes on this particular mb. No more or no less. Extra's installed are NOT a bonus. Placement is crucial.

And tighten the standoffs down to the mb tray before lowering the mb and fastening it down with the screws.

hehe, turned on via a wall switch ..................

[profJim]

Re: Locking the BIOS?

Sounds like a real turn on to me

[petersmart]

Re: Locking the BIOS?

The reason why I wasn't too worried about standoffs was that a few years ago I got a mb which came complete with plastic standoffs so never really associated them with electricity supply.

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[parsec]

Re: Locking the BIOS?

While I agree you MUST use standoffs, your cardboard insulator was not a bad idea, even if it did not work perfectly. OTOH, I look at the hundreds of bare contacts floating a few millimeters above the mother board tray when standoffs are used, and I think, is this really a good system? It works, but just barely.

I would not feel bad if I were you, it could be worse. A recent post mentioned how someone was removing their mobo to RMA it, when the PC started... because the PS was on, still connected to the board, and connected to AC power!

[petersmart]

Re: Locking the BIOS?

While I agree you MUST use standoffs, your cardboard insulator was not a bad idea, even if it did not work perfectly. OTOH, I look at the hundreds of bare contacts floating a few millimeters above the mother board tray when standoffs are used, and I think, is this really a good system? It works, but just barely.

I would not feel bad if I were you, it could be worse. A recent post mentioned how someone was removing their mobo to RMA it, when the PC started... because the PS was on, still connected to the board, and connected to AC power!

But does the MB actually use the metal chassis of the case as an earth?

Because it seems a particularly bad idea to me if I think about it (which I never have before), and looking at another mb it doesn't actually look as if it does, since there doesn't seem to be a backplane in that area (or any area really) - all of the back of the mb is varnished except where the flow soldering has taken place and the scews on the front side also seem to have no electrical connection to anything with the standoffs merely acting to provide placement and rigidity to the mb and stop it from shorting out via the soldered connections.

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[parsec]

Re: Locking the BIOS?

The earthing of the chassis is not necessarily related here, as much as short circuits on the mother board, when the component pins on the bottom of the board touch the mother board tray/case under it. Yes that part may be painted, but the pins/wires on the bottom of the board may scratch through the paint, and zap, a short.

Regarding earthing/grounding of the case, let's start with the PS. The PS case is connected to the third wire earth/ground wire of the AC power cord. The PS case is screwed to the PC chassis with four screws. Yes, the PS case and PC case are painted, but at least one of the screws will wear off the paint, or touch bare metal on the screw threads.

Also, the screw holes on the mobo have contacts around the holes that are conductive. Metal standoffs screwed into the case are making electrical contact with it, and the mobo screws touch the standoffs and mobo contacts.

Then there are all the earth/ground wires from the PS cables to the mobo. That does not cover everything, but it's clear that the number of earth/ground connections between the mobo, PS, and PC case are many.

[synack]

Re: Locking the BIOS?

Electrically speaking earth ground is actually a voltage reference point. having a power supply earthed with the motherboard not earthed *CAN* produce extreme voltages... but it's pretty rare. however having the MB grounded as well as the power supply to the same reference point (earth) eliminates that problem entirely

This is one of the reasons why I dislike when people put their motherboard on a table... they are relying on the power supply manufacturer to provide a proper ground reference to the motherboard.

Floating ground is a bad thing, read this

[petersmart]

Re: Locking the BIOS?

Electrically speaking earth ground is actually a voltage reference point. having a power supply earthed with the motherboard not earthed *CAN* produce extreme voltages... but it's pretty rare. however having the MB grounded as well as the power supply to the same reference point (earth) eliminates that problem entirely

This is one of the reasons why I dislike when people put their motherboard on a table... they are relying on the power supply manufacturer to provide a proper ground reference to the motherboard.

Floating ground is a bad thing, read this

But surely the mb is earthed - through the main power supply plug to the board - the 24 pin plug and the 4 pin plug?

And as I say a few years ago I got a mb with plastic standoffs supplied by the mb manufacture themselves.

And after Googling this it seems most opinion is that the standoffs are only there to stop shorts from the underside of the board.

And the reference you supply seems to deal mostly with electrical appliances where an unintentional floating ground can be lethal.

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