So let’s get this out of the best way first. I do know this PC may be very outdated now. I received it totally free from a pal and with my “greater than newbie” electronics restore knowlege, I wish to study additional and if doable repair this pc.
Diagnosing:
Plugging within the AC cable, it stays OFF. Upon urgent the facility button, I can hear followers, HDD and disc reader come to life and stay like that, followers keep at a low velocity like throughout regular operation. No chime, nothing.
After seeing this, I made a decision to swap RAM, attempt all of the slots with only one stick and swap in between 2 ram sticks for every slot at a time. Nothing. So I knew it was time to take it aside, after eradicating the display screen and discovering diagnostic LEDs, after plugging in AC cable, LED1 is inexperienced, which is an efficient signal. After urgent the facility button, LED1 stays on however all different LEDs are off. Followers spinning, now going to MAX velocity after 15 seconds because it ought to when unplugging temp sensor on the display screen, and all the things stays as talked about earlier than. The actual fact followers go full velocity tells me that motherboard works, however important elements do not get correct energy to work. That is the place I received caught as I do not wish to disassemble the iMac additional earlier than doing a little extra analysis. It does react to the facility button, shuts down after holding it down and all.
I wasn’t capable of finding this actual downside anyplace on the web, so I’m asking in your assist. From my analysis it seems as if the facility provide switches on however the motherboard doesn’t energy on correctly, perhaps defective voltage regulators, PSU not sending correct voltage, who is aware of.
My pal gave it to me considering the GPU is useless however I do not assume so from the prognosis up to now. Possibly each, GPU and motherboard are defective, I’m misplaced because it could possibly be something with these machines. It appears that evidently the PSU works by the truth that all accent components get energy however it might simply be “mendacity” to me.
Can anybody present steering on triage or restore for this classic of Mac and described signs?