Originally known as "The New iMac" the iMac G4 was created to replace the iMac G3 as Apple's all-in-one desktop computer. The G4 is easily recognizable by its swiveling monitor mounted above the hemispherical computer. Steve Jobs quoted it as being "a design that will last till the next decade."

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iMac g4 problems when displaying black colour! What is the problem?

Hi,

I've recently bought an iMac g4 on Ebay!

I've noticed a couple of things that are really really strange.

All hardware is ok, it boots up smoothly and everything else is ok. The problem is when displaying pure black backgrounds or deep black colour. I notice blue flashing lines and dots all over the screen (invisible with other colors in the background). What is the cause? Inverter, LCD panel, loose connector on logic board, gpu?

Second question is that The seller said it was a 17", 1.25 ghz, 2gb ram model which should be named powermac 6,1 in system profile.

I've found it has powermac 6,3 which should distinguish 20" model.

I think that previous owner has changed screen and probably messed up with display or something.

Any advice? Should I try buying a new LCD panel?

Answered! View the answer I have this problem too

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What are the last three figures of your serial number?

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This is the whole serial W83490R8QB7

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Apple iMac G4/1.25 17-Inch "FP" (USB 2.0) Specs

Identifiers: iMac USB 2.0 - M9168LL/A - PowerMac6,1 - N/A - N/A

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See if the serial number in the system profiler is the same as the one on the bottom plate.

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Connect to an external monitor before spending any money. If you see the same thing its the GPU/VGC logic board acting up. If you don't its in the internal display chain… most likely the LCD.

If this answer is acceptable please remember to return and mark it.

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It was my first thought! I've already ordered a mini VGA to VGA adapter which is almost impossible to find here in Italy :( ordered one from China on eBay and waiting for the item to arrive.

If it's ok and the problem is in the display, what do you suggest? It's faulty LCD panel and it could be as simple as changing it??

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As I said I'd wait until the test result is in…it could be the VPU (it's old solder can fracture if one of the legs is not making good contact that could cause the problem) the video display data cable/connector or the LCD… here's a link that may be helpful or encouraging.

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