PSU works, but connected to motherboard does not

[Behemot]

Re: PSU works, but connected to motherboard does not

I replaced all 4 primary diodes 2a05 with R207, because I didnt found 2a05, but can I replace these diodes with kbp06 bridge rectifier ?

2A diodes are probably OK for 200-300 watts. KBP06 is the same, 2A. If you have something for 3+ A, that would be better. But for testing purposes, each of those components is fine, if they are good and it does not work, than the problem is elsewhere.

Would you be able to test is voltage is present on primary capacitors? You must be sure nothing can touch anything conductive otherwise it can go bang (I often use non-conductive things to ensure the PCB cannot touch casing even if it moves). Also be extremely carefoul, there is high voltage! I suggest pluging the cable into PSU, setting up everything and than pluging the cable into wall. After taking measurement and unplugging it from electricity, be sure the capacitors are discharged before you touch anything - check their voltage using multimeter once again. I myself usually wait for the voltage to drop under 20 V, than it should be safe to manipulate.

[senz_90]

Re: PSU works, but connected to motherboard does not

You can use a series light bulb for test purpose. it makes your replacement parts doesn't blow again if something still shorted on your PSU.

read this
https://www.badcaps.net/forum/showth...ies+light+bulb
https://www.badcaps.net/forum/showth...ies+light+bulb

or maybe search on google
to find out how to connect the bulb and how to see the sign.

after the bulb lit a while and slowly dim that means no short anymore and you can test voltage across mains caps like behemot suggest.

[ciki022]

Re: PSU works, but connected to motherboard does not

I have question regarding dim light bulb tester
I am in Europe, line voltage 220 V 50Hz, and all schematics that I have found are for 110 V 60Hz, and they show that on live wire should be the switch, not the way around
In Europe, power cord can be inserted in both ways, it is simertical
Is this, to know which wire is live, is really important for this purpose ?

[Behemot]

Re: PSU works, but connected to motherboard does not

WTF, you have to use grounding! OFC it is important, want to get electrocuted?

[ciki022]

Re: PSU works, but connected to motherboard does not

Yes, my house installations have proper grounding, and I am using proper cords with ground connector ( PC power cords have the ground )
But I dont know which one is live and which one neutral, and Schuko sockets can be inserted both ways ( probably the same is in Czech Republic )

[senz_90]

Re: PSU works, but connected to motherboard does not

Yes, my house installations have proper grounding, and I am using proper cords with ground connector ( PC power cords have the ground )
But I dont know which one is live and which one neutral, and Schuko sockets can be inserted both ways ( probably the same is in Czech Republic )

buy this pen if your town available sell it. when the lamp lit, there is LIVE.
people surrounding my town use this to know where is the LIVE line to avoid shocked.

[Behemot]

Re: PSU works, but connected to motherboard does not

Yes, my house installations have proper grounding, and I am using proper cords with ground connector ( PC power cords have the ground )
But I dont know which one is live and which one neutral, and Schuko sockets can be inserted both ways ( probably the same is in Czech Republic )

Oh you are using the damned Schuko? We have grounding pin as frenchs have so you cannot plug that the other way around. It will work either way but you want to turn the phase on and off, otherwise there would be voltage all the way up to the system, only curret won't flow because of neutal turned off, but you may close the circuit if you touch something.

[m111920]

Re: PSU works, but connected to motherboard does not

I had same problem with some PSU before, problem was in PG line, (POWER_GOOD). When plugged in motherboard and turned on by shorting PS_ON to GND, all pc components started to spin but there is no post. problem is that PG line didn't have any voltage and if I remember correctly, it's supposed to give voltage few milisecunds after PC turn on

[Behemot]

Re: PSU works, but connected to motherboard does not

It should give +5 V on PG.

[m111920]

Re: PSU works, but connected to motherboard does not

C/P from wiki:

The ATX specification defines the Power-Good signal as a +5 volt (V) signal generated in the power supply when it has passed its internal self-tests and the outputs have stabilized. This normally takes between 0.1 and 0.5 seconds after the power supply is switched on. The signal is then sent to the motherboard, where it is received by the processor timer chip that controls the reset line to the processor.