⟐ Answered 五月 30, 2026 at 7:28 GMT-7

根据网上进行reset pram, smc, 都无法恢复

请教各位

⟐ Answered 八月 18, 2025 at 9:57 GMT-7

⟐ Answered 九月 24, 2024 at 20:24 GMT-7

我只用了一年多

⟐ Commented 六月 28, 2026 at 15:18 GMT-7

I have an iMac 2009, 21,5" which has been working well until last week. First there was some flickering and sometimes a black display. Since yesterday the display seems not to work anymore.

I have found the apple technicians guide for this iMac online and tried some of the solutions described there. I did a SMC/PVRAM Reset, but this did not solve the problem.

To determine if it's the gpu I connected an external monitor -> everyhing working fine on the external monitor.

It seems that the LED backlight isn't working anymore, because if you use a flashlight you can see everything on the internal screen.

I asked at a local repair store but they told me (without looking at the device...) that it was either the LCD panel, which would cost almost 500€/650$ to replace or the SATA/Board (Logic board?) which would even be more expensive.

My question is whether it's possible to determine if it is the logic board, ta cable connection, the Backlight controller or the LCD-Panel.

Thanks fpr your answers,

Max

⟐ Commented 六月 27, 2026 at 12:28 GMT-7

I've removed the power supply and I'm measuring the voltage. With no load, they all read 11.88V (any of the right pins with any of the left pins). Then I press the switch on button, all pins go down a little (like 11.82V) but the rightmost left pin + any of the right pins read ~9.22 for one second, they go up to 11.88V, then down again, then up and down, etc.

In a picture I've found on the internet, this "rightmost left pin" is marked as ground.

The point is: is this behavior right? Should the ground pin have 12V, 0V, or what?

Ps.: I'm from Brazil and English is not my first language.

Red: negative pins
yellow: neutral (? maybe not) pin
blue: positive

PSU details

Model details

Voltage reading between any one positive and one negative pin

Voltage between neutral and any positive pin when computer is trying to boot up. The reading fluctuates between 11.8V and 9.2V consistently - i.e., when trying to boot up voltage goes down, fan spins briefly, stop, voltage goes up, rinse and repeat

Reading between any negative pin and neutral pin when the process described above is happening. Voltage goes from zero to 2.5V at the same time the above process is going from 11.8V to 9.2V

Demonstration of how I'm measuring things. In this example, one negative pin (black probe, left), one positive pin (red probe, right)

mobo for reference (side 1)

mobo for reference (side 2)

Extra information: all tests were done with RAM installed and with no RAM installed, same results. Also, sometimes, for no clear reason (at least to me), after probing the mobo randomly with my multimeter (hoping some fairy could tell me what's wrong :-D ), the mini boots up - I hear the chime. But after turning it off and then on again, the miracle stops working.

⟐ Edited by author 六月 27, 2026 at 11:30 GMT-7

I deconstructed my iMac and made it into a functioning external monitor after it broke.

I want to re use the iSense camera by making it a USB device. I have heard of people soldering the cables onto a USB for use. The issue is, there is 7 wires and I am not sure which wires to attach to the USB as they only have 4 connections. I have attached an image.

Thanks in advance

⟐ Commented 六月 22, 2026 at 8:01 GMT-7

I would be happy to post a 'technique' article showing people how to access and test the power supply in this model if someone can help me determine their proper output values and connector pins.

⟐ Commented 六月 21, 2026 at 14:07 GMT-7

⟐ Commented 六月 15, 2026 at 6:26 GMT-7

But what I don't know is if I can only upgrade to a low power chip (S suffix) or if I can upgrade to a full power desktop chip (no suffix). I've seen people upgrade their i5 2400S 27" iMacs to i7 2600, but I've never seen anyone tried a CPU upgrade on a 21.5" imac before let alone the highest end CPU offering from Apple on the 21.5" Mid-2011 iMac is only an i7 2600S.

Now the performance difference between the i7 2600S and i7 2600 is negligible for me, but the problem is I can't souce any i7 2600S but I can fine loads of people selling their i7 2600.

So if anyone can answer, please do as I will apreciate it greatly and if anyone is selling or knows someone who sells an i7 2600S that can ship to Indonesia please answer too. :) Thanks in advance.

⟐ Commented 六月 14, 2026 at 2:13 GMT-7

Turns out iFixit sent me one too many adhesive stripes of the same type and left the other one out. Iam missing the 02 adhesive strip and have the 01 adhesive strip two times.

I have now cut it in proper form and was wondering if I would have to redo this job once ifixit will provide replacement.

I couldnt leave it open and the glass laying around as I got a little kid at home.

here are some Images:

looking forward to your replies. I really dont want to do this again. It seems like it would only be 2/3% of the adhesive strip missing, I personally think its fine as it will stand on a desk and be rarely touched.

Thanks in advance!

⟐ Commented 六月 09, 2026 at 1:56 GMT-7

UPDATE 5/19/15

This problem is becoming much greater with my customers. The anti-virus programs are not blocking sites like "pchelpandsupport.biz" which locks up Safari. Anyone have better suggestions on preventing this kind of attack?

UPDATE 6/6/15

got'um

MacKeeper refund ads will run on Facebook as part of class-action lawsuit settlement

http://www.pcworld.com/article/2927032/a...

UPDATE 1/12/17

Phishing & Other Suspicious Emailsbold text

http://www.apple.com/legal/more-resource...

⟐ Commented 六月 06, 2026 at 0:02 GMT-7

⟐ Edited by author 六月 05, 2026 at 18:46 GMT-7

⟐ Answered 五月 27, 2026 at 6:05 GMT-7

⟐ Answer edited 五月 26, 2026 at 9:16 GMT-7

One end clips to the underside of the “power button assembly”, and another clips to the “antenna housing”.

PICOEZMATE is what the wire and connector are called.

edit: This seems to be the way

https://www.youtube.com/watch?v=dhEsgx8O...

⟐ Answer edited 五月 30, 2026 at 5:59 GMT-7

When I connected an external VGA monitor, I saw it did boot to the “No boot device” screen, which was expected since the original HDD was removed due to failure.

Eventually a MacOS install CD got stuck, so I opened it up and removed it manually. After that, the behavior changed. It now chimes with the green power LED, then as the external monitor briefly detects a signal, it shuts off.

If I try again right after, the power LED comes on but nothing else happens. No chime, no video, nothing until I power it off manually. After unplugging for a few seconds and plugging back in, it goes back to the initial state where it chimes and then shuts off when it should show video on both CRT and external display.

What can I do? I replaced the PRAM battery and it made no difference. It also shuts off before I can do a PRAM reset (Opt+Cmd+P+R), and the physical PRAM button hasn’t helped either.

Trickle voltages seem normal, but when it reaches the “power LED only” state, the down-converter board trickle voltages are lower than normal.

I can also hear the high-voltage crackling as it powers off, so I assume the CRT is receiving power in some way. One other thing of note is that either the speakers, or the down converter board make a high pitched sound, I'll attempt to identify the source later today.

⟐ Commented 五月 19, 2026 at 3:45 GMT-7