iMac in reboot loop black screen and chime, keyboard not recognize.

Question

iMac Intel 24" EMC 2134 and 2211

Model A1225 / Mid 2007 and Early 2008 / 2.4, 2.8, or 3.06 GHz Core 2 Duo processor

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Jim @jimks

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Gönderildi: 5 May 2020

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iMac in reboot loop black screen and chime, keyboard not recognize.

Hi,

First of all, I have to thanks the all community on Ifixit. So many Topics helped me so much. Now I guess it is my time to ask you guys some help, please.

My iMac (VM831NV60KM) suddenly stopped working while I was using it.

Now, it’s rebooting in loop with black light, chime, fan but no keyboard recognized .

LED Diagnostic showed 4 LED lights are working. all ON, I mean.

I’m wondering if the problem can be the CPU, Logic Board, or power supply? CPU and power supply should work if the all 4 LED lights are on, isn’t? So it’s the Logic Board?

Thanks for your help.

cheers

Jim

Bu soruyu yanıtla Ben de bu sorunu yaşıyorum

Bu iyi bir soru mu?

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3 Yorum

Hi @mayer any chance to have your expertise on that please ? I have read many many of your expertises and you’ve always been meticulous and pro. Some articles close to my issue have been checked for you, so I am wondering if you can help me a bit please ?

thank you jim

Jim tarafından 6 May 2020

What type of keyboard are you using?

mayer tarafından 6 May 2020

Hi @mayer thanks for replying.

I use a USB apple one. I plugged a USB computer mouse, I have seen its light. but couldn't see any lights from the keyboard, I tried with a another keyboard but not a apple one, no light as well.

so I did all the commands like, ALT, D, Cmd + R, alt + Cmd + P + R, obviously it didnt worked.

I tried to boot the imac with a usb key. everything was the same. It is just rebooting in loop.

Jim tarafından 6 May 2020

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5 Cevap

Hi @mayer any chance to have your expertise on that please ? I have read many many of your expertises and you’ve always been meticulous and pro. Some articles close to my issue have been checked for you, so I am wondering if you can help me a bit please ?

thank you jim — Jim
Hi @mayer thanks for replying.

I use a USB apple one. I plugged a USB computer mouse, I have seen its light. but couldn't see any lights from the keyboard, I tried with a another keyboard but not a apple one, no light as well.

so I did all the commands like, ALT, D, Cmd + R, alt + Cmd + P + R, obviously it didnt worked.

I tried to boot the imac with a usb key. everything was the same. It is just rebooting in loop. — Jim

mayer @mayer İtibar: 685,3b MacHale Enterprises 3,4b 1,1b 2,6b · Answer 1 · 2020-05-07T08:49:14-07:00

En Yararlı Yanıt

mayer @mayer

İtibar: 685,3b

MacHale Enterprises

3,4b

1,1b

2,6b

Gönderildi: 7 May 2020

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Apple iMac 24-Inch "Core 2 Duo" 3.06 (Early 2008) Specs

Identifiers: Early 2008 - MB398LL/A - iMac8,1 - A1225 - 2211

This is a very unusual case.

I would first try the keyboard in all the USB slots.

I would be inclined to go for the power supply first. These things can partially fail and supply power to things and not others. Pull it and look for bad capacitors (cans). This was a major issue about the time your machine was produced. Bad caps may have swollen tops and/or show leakage.

UPDATE 5/26/20

If I remember correctly, this machine came with system installation DVDs. Please insert the install DVD, hold down the C key and boot from it and tell us your results.

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We Computing @wecomputing İtibar: 67 3 · Answer 2 · 2020-05-05T13:40:44-07:00

We Computing @wecomputing

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hi , i doubt it is the CPU , they are rare to go faulty but logic board -Yes if not light at all after 5 min ,

all the best

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1 Yorum:

Hi, thanks !! Well, I am happy to buy a Logic Board and replace it but I'd like to be quite sure. Yep back light then chime then it reboots. 4 led lights are On. Any more advices or things to check ?

Jim tarafından 5 May 2020

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Jim @jimks İtibar: 1 1 · Answer 3 · 2020-05-08T06:51:35-07:00

Jim @jimks

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Hi @mayer

I checked all usb nothing worked.

i checked the power supply but I have no idea of what is good or wrong so here some pictures

one place looks darker… like I said I don’t know if it’s normal or not.

then when I remove the thin cable, the “thermal paste” ? Had a crack but still in place.

Aslo I just remember, before the imac crashed, days before I had the screen turning black for few seconds or even minutes…while i was working with.

thanks @mayer

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I'm not seeing anything unusual on the power supply. Next carefully examine the logic board looking for a burned component.

mayer tarafından 8 May 2020

I will check then. do you think there will be any issue with the little thermal paste's crack ?

Jim tarafından 8 May 2020

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Jim @jimks İtibar: 1 1 · Answer 4 · 2020-05-08T11:32:39-07:00

Jim @jimks

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The logic board is even more fine

i mean nothing looking bad noticeable.

So yes like I said. Before the iMac crashed. I had the screen turning black for no reason. Sometime secs sometime minutes. I don’t know if that can help

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@mayer or anyone, any recommendations ? thanks

have a great day

jim

Jim tarafından 11 May 2020

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