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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no video on iMac g4 20

I bought an Imac g4 20"1,25 Ghz, for a few euro's, with no video on the screen.

The guy told me: i think the video issue is about a cracked video-cable. Oke, the risk was mine.

Well, it could be possibly anything of course, so i went on searching for the problem.

Indeed, no video, not even a grey display.

Bought a mini-vga>vga cable: but alas, still no succes.

I was able to start in Target mode hooking it up to my powerbook g4, the 80GB HD appeared on the screen

was able to read it and removed personal things from the previous owner. Imac starts up, sounds the chime, reads DVD's, so there is a little bit of hope....

what i'n gonna doe is: 1 replace pram battery first and at the same time inspect the video connection of the logicboard, upgrade ram (original 256MB now). if that does not work out, remove the neck, check the inverter, etc.

to be continued (iguess....)

every suggestion how to solve this prob and make a wonderfull Imac is more them welcome.

Luuk Sollie

Update

Hello there,

things are getting better.

with a mini-vga tot vga adapter from Apple (thrird party adapter did not work) i do have a picture on an external lcd-monitor.

I added 1 GB ram and an airport card, installed Leopard (runs fast enough)

but still no picture on the internal lcd, which is recognized by the way,

not a sign that it is trying to give a pciture, it stays black, with a torchlight there is nothing to see (in case the inverter is broken.

(but mic works, sleep light is blinking when activated),

My question is: does it make sense to open the lcd housing and check whether the cables are properly connected, or do i have to open the Imac, and check the LB connections (next step).

any advice is more than welcome.

Luuk Sollie

Update

Still working (but not every day :) on this Imac g4 20. Will the video cable from an Imac g4 17" fit into the 20" version? Or will it be possible to replace the 20" with a 17" LC from Imac g4?

Answered! View the answer I have this problem too

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If your external monitor is not working via your mini vga (if that's the correct hook up), then you're not generating a video signal and the GPU is gone. Nothing to do but replace the logic board. You'll need to stay with the same GHz board as the earlier ones have different power connectors.

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thanks Mayer, bit i thought G4 Imac is only capable of mirroring the original lcd on an external monitor, so: if you don't have a display on your lcd there's nothing to mirror :).

there's a patch somewhere to make an extended desktop possible,but i can't install it because the lcd fails.

is there any change the video chip got lose and resolder it? (the so called "reflow - procedure? (I did it several tmies with a windows laptop).

and indeed:mini-vga is the correct hook-up.

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Your logic on mirroring is faulty. It's true if your monitor is working, but your's is not. The second monitor tells us if your machine is generating a picture and may be fine on an external, telling us that the break is between the GPU and the LCD.

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My iMac has the same issue with LCD. I found LCD itself was defective (idtech m201z2 ).

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Luuk will be eternally grateful.
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