Resolved Bad graphics card?

[rgwoehr]

I have a mid-2007 iMac, 2.4Ghz, 2GB RAM, with an ATI 2600 pro. When I press the power button, it would chime and boot up but there was no video output from both the internal LCD and an external monitor. When I connected via screen sharing and opened System Profiler, nothing showed up under Graphics/Displays. When I opened it up to look at the diagnostic LEDs, the #4 LED was off or would flicker (the flickering only happened once).

After doing some research I bought a used graphics card, and when I installed it, it wouldn't chime at all. I can hear the hard drive spin up and then the fans start spinning at the maximum RPM. Diagnostic LED #4 still stayed off. I tried resetting the SMC but it didn't help. If I remove the graphics card it boots normally. Is this new graphics card bad or is it something else?

 

[jav6454]

Which GPU did you buy to replace it with? Also, call me crazy, but I don't think 2007 iMacs had a replaceable GPU.

 

[rgwoehr]

I bought a 2600 Pro. They have an MXM slot for the GPU. I forgot to mention that it's a 20" if that makes any difference.

 

[jav6454]

I bought a 2600 Pro. They have an MXM slot for the GPU. I forgot to mention that it's a 20" if that makes any difference.

Then it might have not been the GPU and it could well be the logic board. However that is very unlikely. I guess I would recommend returning the GPU you bought or go for an exchange for another card to test.

 

[rgwoehr]

I pulled out the graphics card and started it up and LED #3, which indicates that the computer and the video card are communicating, stays lit. I'm guessing that means it's the logic board, since it thinks it's communicating with a graphics card that isn't installed.

 

[rgwoehr]

I finally got a replacement logic board and installed it, and I'm having the same problems. It was supposedly tested and fully functional. If that's true then is it possible that both graphics cards I have are bad? It won't POST with one of them and with the other one it boots but doesn't recognize it. With no GPU installed LED #3 still lights up.

 

[rgwoehr]

Then it might have not been the GPU and it could well be the logic board. However that is very unlikely. I guess I would recommend returning the GPU you bought or go for an exchange for another card to test.

Just thought I would update the thread now that the problem is solved. You were right, the graphics card I bought was bad. I took one out of a known working machine and put it in the other iMac and it worked fine.