Note to mods: please remove the first thread i posted. It had crappy title. Hopefully this will make some powermac expert look at it more likely
So i bought PowerMac G5, which worked for around an hour. Then i decided to partially strip it down and re-paste CPU, after which it still worked. However just after i added DDR2 memory into it and connected it to 220v, the mac made a loud pop noise, diagnostic leds on the front side of motherboard shortly blinked and since then, the power mac has no signs of life at all
PSU is API4fS13. There is no visibly broken component on the PSU. No bloated capacitors, no exploded mosfets, nothing.
I tested several stuff:
5V standby line seems to have some sort of voltage spike after i plug psu in (my multimeter on 20V setting displayed overrange for split second) and then settles to around 0.05V or lower.
Bridge rectifier clearly works. High voltage capacitors are getting charged and after i disconnect the PSU, they keep their high voltage for a very long time (tens of minutes), which probably means, that there is nothing to drain them to. I'd expect, that if the standby line was operating properly, they'd drain a lot faster.
I tried shorting PS_ON on the PSU to ground. Nothing happened
I tried applying 5v to standby rail on motherboard. LED lit up informing me, that i should insert CPU so motherboard very likely isn't toast
I tried manually triggering the relay, that seems to enable the non-standby lines (PSU always clicked two times after i plugged it in, but since the failure, it no longer does that, and PSU always clicked when i turned the mac on). Relay worked as expected. I could see, that the positive output from bridge rectifier goes to the relay. I presume 5v standby line just bypasses the relay.
I measured internal diodes on multiple MOSFETS and all reported pretty much same values. I also found two IGBTs (20N60C3), that have got G and E pins shorted, which is weird.
5V and 25V standby lines are next to each other, which complicates stuff quite a lot. It seems like both rails are controlled by one MOSFET and one transformer.
Should i try posting the pictures of the board and try to annotate my findings? Did anyone ever try fixing this PSU? I found one guy on this site, but he had faulty bridge rectifier and shorted MOSFETs, which i'd have detected already.
Should i post pictures of the board and try to annotate them with what i had checked?
**
So i bought PowerMac G5, which worked for around an hour. Then i decided to partially strip it down and re-paste CPU, after which it still worked. However just after i added DDR2 memory into it and connected it to 220v, the mac made a loud pop noise, diagnostic leds on the front side of motherboard shortly blinked and since then, the power mac has no signs of life at all
PSU is API4fS13. There is no visibly broken component on the PSU. No bloated capacitors, no exploded mosfets, nothing.
I tested several stuff:
5V standby line seems to have some sort of voltage spike after i plug psu in (my multimeter on 20V setting displayed overrange for split second) and then settles to around 0.05V or lower.
Bridge rectifier clearly works. High voltage capacitors are getting charged and after i disconnect the PSU, they keep their high voltage for a very long time (tens of minutes), which probably means, that there is nothing to drain them to. I'd expect, that if the standby line was operating properly, they'd drain a lot faster.
I tried shorting PS_ON on the PSU to ground. Nothing happened
I tried applying 5v to standby rail on motherboard. LED lit up informing me, that i should insert CPU so motherboard very likely isn't toast
I tried manually triggering the relay, that seems to enable the non-standby lines (PSU always clicked two times after i plugged it in, but since the failure, it no longer does that, and PSU always clicked when i turned the mac on). Relay worked as expected. I could see, that the positive output from bridge rectifier goes to the relay. I presume 5v standby line just bypasses the relay.
I measured internal diodes on multiple MOSFETS and all reported pretty much same values. I also found two IGBTs (20N60C3), that have got G and E pins shorted, which is weird.
5V and 25V standby lines are next to each other, which complicates stuff quite a lot. It seems like both rails are controlled by one MOSFET and one transformer.
Should i try posting the pictures of the board and try to annotate my findings? Did anyone ever try fixing this PSU? I found one guy on this site, but he had faulty bridge rectifier and shorted MOSFETs, which i'd have detected already.
Should i post pictures of the board and try to annotate them with what i had checked?
**
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