renanbianchi Posted May 10, 2020 Report Share Posted May 10, 2020 (edited) Hey guys, i' got this 1.6 PSU that seems to be turning the 12v line OFF after some time until it stops feeding it at all. The PSU was burned and repaired by other than me. It seems to be working perfectly, as i made a jumper from the 12v capacitor and it does indeed boot and work for hours, so it must be some component that's responsible for turning off the 12v line on it that is shorted or not operating properly. The thing is, i can't see any damaged component. All the other lines do work and the power button does seem to function. I've been trying to track what component turns off the 12v line when i turn off the console, but to do that i'd need a spare 1.6 PSU which i don't have at the moment. It's a Delta PSU by the way. I've made another post on this forum about the issue but it was in the wrong section. Also i didn't had a clue about what was making the PSU turn off until i found it was the 12v line. Edited May 10, 2020 by renanbianchi Quote Link to comment Share on other sites More sharing options...
SS_Dave Posted May 10, 2020 Report Share Posted May 10, 2020 I have seen posts suggesting that the a rectifier has failed and that's causing a low 12 volt supply. There is 2 on this heat sink I would suspect the bigger one is the 5 volt and the smaller one for the 12 volt I would test the 12 volt switch transistor 1st. The metal tab should read approx 12 volt with the Xbox in standby(plugged in and not on) and the same when running if the reading drops when running then look at the rectifier pack if no change in voltage then I would replace that part. Maybe upload a pic of both sides of the power supply. Cheers SS Dave Soft modding is like masturbating, It gets the job done but it's nothing like the real thing. Quote Link to comment Share on other sites More sharing options...
renanbianchi Posted May 11, 2020 Author Report Share Posted May 11, 2020 (edited) On 5/1/2020 at 7:09 PM, SS_Dave said: Are the caps near the 20 pin power connector on the main board in good condition? Maybe post some pic's of the power supply and the main board? Cheers SS Dave Soft modding is like masturbating, It gets the job done but it's nothing like the real thing. Hey Dave, thanks for the reply. I did test the motherboard with another psu, so it is working fine. The switches do seem to be working fine, so I'm trying to track what component would be bad. Maybe one of those little black transistors could be the culprit? There isn't any damaged resistor nor diode that I saw. All the caps on the PSU have been properly replaced so they're working fine. Pictures have been attached. As you can see, i've replaced a lot of components on this board lol. But it is working perfectly except the 12v line not turning on. Edited May 11, 2020 by renanbianchi Quote Link to comment Share on other sites More sharing options...
renanbianchi Posted May 11, 2020 Author Report Share Posted May 11, 2020 (edited) I've found the problem. The rectifier was good and working perfectly. I've traced it after studying how that MOSFet transistor works. It needs a higher voltage to be turned on, so i traced back to find that there was a 13V source that should go to it, but it was measuring 0.3V only, so the mosfet would never turn on. So I've found the culprit, it was a Shorted zenner diode just behind the mosfet. I've replaced and got it back to work! Thanks for your help, as it convinced me to study how it worked and find the problem. Edited May 11, 2020 by renanbianchi Quote Link to comment Share on other sites More sharing options...
SS_Dave Posted May 11, 2020 Report Share Posted May 11, 2020 Well done that's really good to here you have fixed it. Cheers SS Dave Soft modding is like masturbating, It gets the job done but it's nothing like the real thing. 1 Quote Link to comment Share on other sites More sharing options...
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