Anyone have experience with these devices that could shed some light on my troubleshooting journey. I ended up receiving this one awhile that was working and swapped out the internal HHD for an SSD following an iFixit guide and upgraded the RAM to 4GB. After a few years the system was getting pretty dirty so I was able to disassemble it again and clean out the internals and replace thermal paste on both the GPU and CPU while I had the system opened up. Upon putting the device back together I noticed that the screen would not turn on and the fans would kick in 100% and the white power light would be steady.
I took the device apart and verified that all the cables are attached properly and after looking at the green LED diagnostics on the front I noticed that only 2 out of the 4 are lit. When plugged into power the first green LED becomes lit and once I press the power button the second LED lights up but the remaining two would not illuminate.
After some investigation I read that it means that there is no communication to the GPU. I said fair enough and reseated the GPU and tested the pins with a multi-meter and was able to get continuity from the GPU to the logic board. Still no luck. I then ordered a working NVIDIA GeForce 7300GT from eBay and same thing. Black screen, fans at 100% and two green LED lights on.
After spending hours reseating connections, testing RAM and RAM slots, cables, PRAM reset, etc. I gave up for a little and just now decided to take another look at the system. I found an eBay listing for a working A1200 logic board with a CPU. After it arrived I went ahead a installed the new motherboard excited to finally be done troubleshooting and to my surprise I am still getting the same issue: Black screen, fans at 100% and two green LED lights on.
At this point the only thing I have not replaced is the power supply, screen, and case, Which at this point I would have built another system. The fact that it was working fine before I swapped out the paste and cleaned the dust baffles me. I am pretty adept with laptop/desktop tear downs and worked on hundreds of systems back in my desktop support days when I was younger so something like thermal paste is a walk in the park for me (until I met iMacs).
It would be great if someone could help shed some light and info on this iMac generation since I don't have too much experience working with these systems or any suggestions for me. I really love the look of this iMac generation and hate to scrap it and just buying another system. If you have any questions or want any pics feel free to ask!
Thanks!
I took the device apart and verified that all the cables are attached properly and after looking at the green LED diagnostics on the front I noticed that only 2 out of the 4 are lit. When plugged into power the first green LED becomes lit and once I press the power button the second LED lights up but the remaining two would not illuminate.
After some investigation I read that it means that there is no communication to the GPU. I said fair enough and reseated the GPU and tested the pins with a multi-meter and was able to get continuity from the GPU to the logic board. Still no luck. I then ordered a working NVIDIA GeForce 7300GT from eBay and same thing. Black screen, fans at 100% and two green LED lights on.
After spending hours reseating connections, testing RAM and RAM slots, cables, PRAM reset, etc. I gave up for a little and just now decided to take another look at the system. I found an eBay listing for a working A1200 logic board with a CPU. After it arrived I went ahead a installed the new motherboard excited to finally be done troubleshooting and to my surprise I am still getting the same issue: Black screen, fans at 100% and two green LED lights on.
At this point the only thing I have not replaced is the power supply, screen, and case, Which at this point I would have built another system. The fact that it was working fine before I swapped out the paste and cleaned the dust baffles me. I am pretty adept with laptop/desktop tear downs and worked on hundreds of systems back in my desktop support days when I was younger so something like thermal paste is a walk in the park for me (until I met iMacs).
It would be great if someone could help shed some light and info on this iMac generation since I don't have too much experience working with these systems or any suggestions for me. I really love the look of this iMac generation and hate to scrap it and just buying another system. If you have any questions or want any pics feel free to ask!
Thanks!
