Today I tried to shoot the problem, powered the PSU on, followed the 324V path to the transformers.
First I found the 324V on the right big one, then the same voltage is passed to the small one via 1 ohm 1/4W resistor and it turns out the resistor is cracked!
I replaced the resistor and powered on the unit again and there wasn't any voltage even the mains voltage is off, because the plus fuse is blown!
Should I replace the fuse and try again?
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Hi, could you please check my latest update to the thread?
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You could also buy yourself a diff probe...say a TA041....then you can probe it.
i presume the tny280 is set up as a flyback, so can you see if the input voltage is getting to it or not?
You are right you shoudl be able to see voltage between drain and source.....if its not working you should get the rectified hv dc...but if its working you will get the switching of the drain.
So are you gong to see that the TNY280 works first?
But Betwixt is right there is a connection that yuo can make with those pc power supplies that you need to make to get it to work....this is needed when you have the PSU removed from the PC, which is what you have done there.
Thanks for the tips, I checked the diff probe, I think it would be a nice tool to have, but how it works?
Yes, I hope you check my latest post today.
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OK, I connected another power cable and hoped it won't blow up something, but it went well.
I checked the voltages, now I'm getting 5V on the purple rail, but 0V on the other cables.
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Now this is my analysis for the two transformers. According to #22
The TNY280 is supplying the standby voltage, that's why I'm getting 5V on the purple rail.
The ICE2PCS02 is supplying the main output transformer, so if nothing on the output rails then this IC could be broken.