Bad Display / Graphics Problem with iMac 24" 7300GT
hoping someone can help me with this.
So I assumed the problem was a faulty video card (7300GT) so I bought a new one and fitted it, correctly as I've done this a few times before.
However I'm still getting weird artefacts on the screen, thinking about it they ar different to the ones you get with the GPU overheating/sol
See the attached screenshots (a combination of red and blue repeating patterns across the screen that redraw whenever you alter the display, i.e. move a window)
So, although not totally ruling out the video card I'm at a loss as to what the problem is.
1.New GPU hasn't helped
2.Artefacts appear on startup (Not software then?)
3.Don't appear to be heat related (SMCfancontrol makes little/no difference)
4. Known working LCD does not alleviate problems
5.Logic board in good superficial condition, I can't see any obvious problems.
6. RAM known working
7. Safe mode makes no difference
So hopefully someone can figure this out?
What I'm leaning towards is
1. Bad new video card?
2. Bad VRAM?
3. Bad GPU daughtercard?
4. Bad Logic board to GPU interface?
5. Bad logic board?
6. Power Issues?
7. LCD cable problem?
Many thanks in advance!
Hook it up to an external monitor to help isolate the problem. If the artifacts are present on the external then the problem is hardware/video card related.
The 7300GT has a known issue with the capacitors on the card. The 7600GT was also an option for your iMac. They cost a bit more but you may consider it a cost effective repair vs the 7300gt loto.
Getting the same issue with an iMac using this GPU. It started right after upgrading the OS to Lion. Unplugging the computer for at least an hour "fixes" the system temporarily as it resets the SMC. Issue comes back and gets progressively worse over the course of a few days. For me, downgrading back to Snow Leopard was the "fix".