Hallo @ all,
my name is Torsten, I am german but living in Paraguay. My profession is graduate engineer for electronic components.
Yesterday here we have had a power blackout and after this my computer does not work anymore. If I started it, it swiched off after 2 - 3 seconds. CMOS-reset does not show effect.
So I removed all components inside apart from the cpu and fan and connect only the power connectors for the mainboard. The error code tells me 3 beeps - memory missing. That is correct and it does not switch off. So I think that the cpu works. But if I test the voltage I see that the 12V only amounts 10,6V and so, if I connect more components, it switchs off again.
Than I test it for a short time without the cpu-fan (using 12V) - the same. Changing the power supply shows the same, so I am sure the powersupply works correctly.
Also if I disconnect the mainboard from power and connect all my 5 drives to the power supply the voltage is constant 12V. It only breaks if I connect the mainboard.
Does anybody have some information to this effect? What can I do? Which components are using this voltage at the board? I was looking for consumers of the 12V at the mailboard, but it is nearly hopeless to find something without a wiring diagram. I found that all the fan-connectors have the 12V and near the cpu are two FETs (SUB70N03), a coil and 3 electrolytic capacitors which are connected with the 12V-voltage. The transistors (it seems) are o.k.
What next? I dont like to change the mainboard, because the boards they can get here are very bad. I would like to repair my board, but for this I need a little help. May be I will found help here at the forum, I hope so.
Best regards
tomue