I need help before I cry.

[tom18230]

why does your brother have a 600w corsair just lying around.... stranger and stranger

It's the way he rolls.

To be honest, you can find anything in his flat. He builds alot of pc's for friends and stuff, so often has spare components lying around. I think one of his friends bought that PSU and realised they needed less power so just bought a new one and gave this to my brother so he could find a use for it.

[Thorsson]

I wish I had a few friends like that!

Just thought I'd ask - you are absolutely sure you have the jumper on the right pins now, aren't you? It would do just what you describe (i.e. nothing) if the CMOS jumper were on the wrong pins.

[MadduckUK]

I think one of his friends bought that PSU and realised they needed less power so just bought a new one and gave this to my brother so he could find a use for it.

as i said, stranger and stranger.. and stranger..

[tom18230]

If you saw my brother, you'd understand. I've heard rumours that he can divide by zero.

Jumper is on 1st and 2nd pins.

[SiM]

Why don't you just ask him to take a look at the pc then?

[tom18230]

Why don't you just ask him to take a look at the pc then?

He's coming up tomorrow to look at it.

[peterb]

Is there a power switch on the back ofthe PSU - near the manins connector? If so, check that you haven't inadvertently switched it off!!!

You could try disconnecting the power switch connector and putting a 20p coin against the two power pins.... the power button might be broke, unlikely, but worth the 20 seconds it would take to do....

This is the soft power switch on the front of the case - be VERY careful doing this - although it is no more than 12 Volts (won't harm you) there is a risk of doing damage to the mobo by shorting more than one. However it is worth checking that the connector from the front panelbutton is connected and connected to the correct two pins.

[Blitzen]

I wasn't suggesting he does this with the PSU plugged in! By the time he has dismantled the PC, and removed the PSU, the caps would have discharged themselves, either through the ccts themselves, or through the bleed resistors that should be connected across them for that purpose!

(The caps on the mains side of the inverter will charge up to about 300 volts, which would bring tears to your eyes, although unlikely to be fatal as they would discharge across a hand - they float wrt earth - and anyway they will discharge quite quickly.

The caps on the output side will charge to the rail voltage, 5V or 12V and is not in itself dangerous, although if you shorted them while they were charged, you would get quite a spark. - depending on the value of the capacitor - remembering that charge (in coulombs) =CV where C is in Farads, and the stored engery (in joules) = CV^2 - again C is in Farads) so a 1000 microfarad capacity charged to 300 volts stores about 90 joules - and being DC is less harmful than the AC equivalent - still give you a belt though!!)

But perhaps I should have added a caveat that you do need to be very careful removing the covers from a PSU - it isn't something to be done lightly, and apart from anything else, may void the warranty. And if you do work on a PSU that has been live in the last hour or so, it is a wise precaution to connect a low value resistor (say 1Kohm) across the main smoothing/ripple capacitors for a few seconds to ensure they are safely discharged.

+++++++++++++++++++++++++++++++++++++++++++++

Back on topic - starting up the mobo with the CMOS battery disconnected would be unlikely to 'fry' the board. The battery is only there to supply power to maintain the CMOS memory while main power is not available to the board, ie when it isn't connected to mains (doesn't have to be powered up - remember that LED that glows?) Removing the jumper disconnects the battery, I don't know if placing it on the other two pins actually does anything (such as shorting the CMOS power input to earth, but even if it does, it is unlikely to cause harm

It is also unlikely to damage the BIOS, which is electical eraseable programmable ROM (EEPROM) which as the title suggests, is erased by applying a voltage to a programming pin, and this is done under the control of utility software - otherwise the bios holds its contents undisturbed.

(Note that I have used the word unlikely - voltage spikes etc can do funny things to electronics, but there are more probable causes for the problem which need to be eliminated before going down the road of despair!)

More likely is that the OP has disturbed a connection to the mobo somewhere while tinkering inside and that is the cause of the problem.

The solution, as has been pointed out, is to stop panicking, inspect the inside of the machine for loose wires etc ,and if necessary to a rebuild, carefully and methodically. It is probably easier to do that outside the case, as that enables a visual check to be made more easily, and once working, gives confidence that all is OK. Then it can be carefully and methodically built back into the case.

Thorsen has described the precise steps very concisely in an earlier post.

As in depth as your post here was, i dont think it helped. Its very in thorough (although one or two points are wrong).
An interesting read none the less though

The can caps will hold a charge far longer than you suggest btw. Thats what they supposed to do Some of the voltage can discharge hours after shutdown.(I saw a little fella in a LARGE electronics manufacturing plant in Korea learn this the hard way - poor bugger but it was funny) The best way to expel this charge is unplug the PSU from the wall, switch it off (if it has a switch) then hold in the power button. This though, still will not completely discharge them.

Your mention of a 1Kohm Res confused me a little aswell. If you can get near enough to connect, the chances are the caps will be fully discharged anyway (through your arm probably).

[Az00123]

Hi, i had this problem with my ip35 dark raider too, so i sent it back to scan and they said they tested it and no faults were found. They also said that they updated the BIOS for me (dunno how they did it when i couldn't get anything to display)

Anyway, when i turned it off, I couldn't turn it back on like you, to be able to turn it on again I had to put jumper to clear, take out battery and remove all power connectors for 15 mins, then I'd be able to put everything back and turn it on but still no display. I tried using diff RAM sticks in slot 1 and there was still no display, I'm gonna try doing what jamena said once i get the board back

[peterb]

As in depth as your post here was, i dont think it helped. Its very in thorough (although one or two points are wrong).
An interesting read none the less though.

<----snip----->

Thank you for the (backhanded? ) compliment!

Capacitors do hold their charge for a long time - if they are not connected in a cct - the only discharge path is self leakage (which can be quite high for an electrolytic) - but in the case of a PSU they are connected to other components so the charge will leak away - and quite quickly. This is particularly relevant and applicable to the high voltage side of the PSU where the incoming mains is recified to form the input to the inverter. A good design would have bleed resistors across them, but cheap 'n' nasty PSUs don't always conform to good design!

(I have just pulled apart a rather cheap and nasty PSU that I've had lying around, and the two smoothing capacitors on the input side are 330 microfarad, 200V devices (under rated in my opinion) but I haven't looked deep enough to see if bleed resistors are present.)

The output side capacitors are around 2,200 microfarad but form part of a LC filter circuit (the output of the inverter is at a high frequency) but as the voltage is low they are harmless - although if they were shorted when charged, you would get quite a healthy spark as the internal impedance is low.

There is the relaxation effect - high voltage paper or mylar or other synthetic dry dielectric can recover charge - so while they may have been safely discharged, they can recover charge and exhibit a high valtage at the terminals some hours later, but this is only really a danger in higfh voltage (over 1KV) devices, and is why they are usually supplied with a shorting link across the terminals. Again, one installed, they present little risk from that effect because of the other devices in cct with them. This was particularly applicable to the capacitors used in voltage multiplier ccts for the EHT supplies in CRT monitors - typically 25KV - although I would never advocate tampering with those as apart from the elecrical hazards, there are other hazards associated with ionising radiation production and the associated shielding. The only other place where you would find that in a domestic environment would be in the PSU for the magnetron in a microwave oven. (In industry you would find similar congurations in power supplies for travelling wave tubes and magnetrons in radar and other high power RF generators, and in high voltage experimental laboratories - but that is not really relevant to this discussion!)

As for applying a 1K resistor, I would apply that using insulated pliers to hold the device - and perhaps I should have been more explicit in the instructions!

There was another comment about "being a little cavalier in suggesting he take the PSU apart" - however if something has been dropped into a PSU - and poses a risk to it - and it can't be retrieved, then there is no alternative, other than junking the unit and replacing it, but perhaps I should have emphasised the safety aspect a bit more.

So - to set the record straight (and we have gone a bit off topic!)

Taking apart a power supply is not somethingto undertake lightly or without some understanding of how these devices work, and what the risks are. If in doubt - don't!

[tom18230]

My brother had a look at it. We tried everything you said, and more.

Took the whole thing apart and put just the mobo, psu, cpu and heatsink outside the case on cardboard. Still nothing.

Definately the mobo, so I've sent it to be RMA'ed today. Should have a new mobo soon. Cheers guys.

Oh yeah, I also found the jumper - inside the PSU. When I took it all out, it just fell right out the PSU. Tried the jumper-less PSU, same thing .