Introdução
The 24-inch 2007 and 2008 iMac's have four diagnostic LEDs on the logic board that can help troubleshoot the computer. A little disassembly is required to locate and observe the LED's. This guide is based on information sourced from the applicable Apple service manual.
**LED interpretation is also applicable to the iMac Intel 20" EMC 2133 and 2210**
O que você precisa
-
-
Loosen the single Phillips screw in the center of the access door.
-
Remove the access door from your iMac.
-
-
Ferramenta utilizada neste passo:Heavy-Duty Suction Cups (Pair)$14.95
-
Stick two suction cups to opposing corners of the glass panel.
Save $15 dollars and use a plunger. Works perfectly.
Perhaps not so elegant but equally effective without any adverse effects to either... try a vacuum cleaner.
The same kind of suction cups are available from Harbor Freight Tools (Item # 62715) for $2.99 each or $5.98/pair (plus sales tax).
-
-
-
Gently pull the glass panel straight up off the iMac.
The glass panel is somewhat thin and should come away quite easily without much force so be gentle.
To reinstall the glass, I lined up the bottom edge first, then pivoted the top in. The magnets pulled it quickly into place.
-
-
-
-
Remove the following 12 screws securing the front bezel to the rear case:
-
Eight 13 mm T8 Torx screws
-
Four 25 mm T8 Torx screws
-
Six 13 mm T8 Torx screws
-
Four 25 mm T8 Torx screws
-
Two 35 mm T8 Torx screws
I only had two 25 mm T8 Torx on my model. (The two inner orange circles as shown in the diagram.)
I don't know if this is different but i am in the process of disassembling a 24' imac emc: 2134. i have only: (2) 25 mm T8 screws the inner two on the bottom of the screen. I have (4) 13 mm t8 screws the outer most holes on the bottom and the 2 holes on the right side of the monitor above the drive entrance and the remaining holes are (6) 11 mm t8 screws
I have the same screws as ccarter on a 2211 except on the bottom row there are only 4 screws total, the longer ones go in the middle two.
My 2211 has a different screw configuration.
2 - 32mm long screws towards the middle of the bottom edge
4 - 18mm long screws (2 at the corners of the bottom edge and 2 along the right edge)
6 - 13mm screws along top and left edges
Mine is the same — two very long, four medium, and six short. Also my T9 worked better than my T8 which was a bit loose.
I have the same screws as Christian. The key is to make sure all screws are flush to the surface, so that the glass can be held up by the magnets.
On mine, for the red circles, I had the six 13mm Torx plus two 25mm Torx. It's not indicated in the picture here, but the 25mm Torx went on either side of the optical drive.
I marked next to each hole with a pencil "S, M or L" to indicate which length screw goes where. No guess work on reassembly.
-
-
-
Gently lift the front bezel from its top edge off the rear case. It helps to use your thumbs to push down very gently on the corners of the display.
-
Once the top edge of the front bezel has cleared the rear case, rotate the front bezel toward the stand and lift it off the rear case.
Looking at the meaning of the LEDS
i've got 3 LEDS on but i don't get a chime or the screen.
i am going to check the inverter voltages but can only find info for the 20" macs iMac Intel 20" EMC 2210 Power Supply Output Voltage Test
does anyone know where i can get info for the 24"
i have the same thing, 3 LEDs on but no chime and no screen.
what is the fix? and problem?
Bill -
-
-
-
Disconnect the microphone cable connector, removing tape as necessary.
I also skipped disconnecting the microphone cable. I have a large table and I stacked some books next to the iMac. There was plenty of cable for the bezel to fold nicely over the top of the iMac.
I used the floor instead of a table and left the cable connected.
-
-
-
Locate the Diagnostic LED's between the RAM slots and the SATA connector.
-
LED 1 - Indicates that the trickle voltage from the power supply is detected by the main logic board. This LED will remain ON while the iMac is connected to the AC power. The LED will remain on even when the computer has been shut down or put to sleep. The LED will turn off only if the AC power is disconnected or the power supply is faulty.
-
LED 2 - Indicates that the main logic board has detected proper power from the power supply when the computer is turned on. This LED will be ON when the computer is turned on and the power supply is working correctly.
-
LED 3 - Indicates that the computer and the video card are communicating. This LED will be ON when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement.
-
LED 4 - Indicates that the computer and the LCD display panel are communicating. This LED will be ON when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement.
I have LED 1,2 and 3 lighting up, LED 4 is off. Does that indicate a videocard issue?
3 leds appear to be the correct status - LED power supply and logic board tests
Hi friend, Your model is 24” a1225 emc2211? I have exactly the same problem...
According to the led test it is a problem of the connection of the display or the video card, but I am almost sure that it is power supply, Did you find any solution?
Victor -
LED 1 lights when I plug in the power. As soon as I touch the power button, LED 1 goes off, and nothing else. All LEDs are off. Unplug and replug and LED 1 lights. This indicates there's no problem with the power supply.
I'm fixing the oft-defective NVIDIA GeForce 8800 GS GPU. I reflowed the GPU and am in the process of seeing if the reflow worked. Before disassembly, the machine could turn on. Now nothing. During the process, I cracked the connector on the power inverter cable that goes from the power supply to the back of of the display.
In my interest to get my iMac together, I placed the single dangling wire on its pin, then placed the two intact sides of the inverter connector on either side. (Gluing the connector together just didn't work.) I plan to order a replacement cable as soon as I can.
Could this wonky cable connection cause the whole system to not function? I think it could, but thought I'd ask. Any other thoughts or gotchas from people who've done this type of work?
Ok, display is black, I have led #1 lit when power is connected, led #2 comes on and stays on when power button is pressed, the fans come on, it checks the optical drive, I hear faint hard drive noise, but led #3 & led #4 do not come on. And I do not get a startup sound. What would this indicate?
Any update on this? I seem to be having the same problem.
2008 24" iMac EMC 2211 Model 8,1 no power. I removed bezel and looked for Led lights. Non lit up. I'm thinking power supply? Thoughts. Video card? Thanks in advance.
it’s possible, I have the same issue. The #1 light is on when plugged in but soon as I press the power button it is gone….then no lights at all. Let it sit for 10 minutes plug it back in …no lights …nothing. I think maybe the power supply. I don’t think you can tell if it’s anything else like the logic board unless you have a known working power supply.
I removed my screen to put in a hdd but after i put lcd back the forth light didnt come on, no display or start up tone.. cant work it out!?
Hi, I have a similar problem? Did you solve it?
On A1224 iMac i have LED 1 On. When I press power switch, led 2 turns on, but nothing more happens. I have not power on sound and fans do not turn on. What do you think is the issue? Videocard issue?
I have light one come on stays on as long as the power cords plugged in light to stays on as soon as it boots or whatever and it makes a sound like 3 stays on but light for does not come on and I have nose thing on my screen but the screen works great prior to me upgrading the paste on my GPU and CP
I get all four lcd lights on but nothing shows up on the lcd panel. Is there a way to test if it the panel or the inverter ?
Chances are you have a bad Lcd. They have fluorescent tubes that make the screen light up. Try a very high powered flash light to check for an image. If you see an I make chances are you need a new Lcd panel.
I had this issue with an old iMac that stood for ages and the onboard battery ran flat. Replaced it and the machine powered on but no beeps or display. 4th LED was off. Only once I had it apart I tried various RAM combinations and got the bong with that. Re-connected everything and all good, including the 4th LED and display. Check the ram with known good RAM and try a few times.
It was the battery! Completely dead iMac A1225 EMC 2134. Was about to recycle it but figured I’d try this tutorial. I initially had just LED 1 green- and then none when I hit the power button. I replaced the PRAM battery and instant Bong and full boot up with 4 LEDs! Thank you for this great tutorial- I would simply add to replace the battery before doing anything major like a power supply.
salve a me mi si accendono tutti e tre i primi led e il quarto no anche se lo schermo si accende ma rimane grigio ,cosa può essere? Grazie
-
To reassemble your device, follow these instructions in reverse order.
To reassemble your device, follow these instructions in reverse order.
Cancelar: não concluí este guia.
66 outras pessoas executaram este guia.
Equipe
11 comentários
Hello,
I have iMac 2008 24" When I turn on the computer no startup sound but DVD / Motherboard / CPU Fan is still on. also two green LED is static on, anyone help me....
Raza
Does anybody know where I can buy the thermopads for the 4 chips on the video card. The ones it already had were all melted and can't reuse them. I appreciate your time and help. Thank you.
Does anybody know where I can buy the thermal pads to put on the 4 chips on the video card? Any help is very appreciated. Thank you.
Imac would not boot up (LED #1 lit only) about 9 months ago so I replaced PSU at that time. iMac was working fine until recently when it would not boot up again. Only LED #1 lit so I replaced the PSU again thinking this would solve problem……it did not. Only #1 stays lit and SuperDrive starts to spin yet no fans or chime or screen.
Question: Any other checks before logic board needs to be looked at or replaced. Is it worth replacing logic board on 10 year old iMac? How long and any special tricks?
Thanks from Florida.
Imac 24 2008 3.06ghz when turn on hear the chime screen on trying to boot up the bar under Apple logo starts moves about quarter way and stops
and would not move any further ,tried holding down all suggested sorts of key combinations no success .I also tried replacing new HDD ,after replacing and switch on screen comes on and display ? at this stage I loaded the Mac OS X Snow Leopard disc in the optical drive ,it starts spinning
the Apple Logo appears and below the logo a buffering circle starts spinning and carries on and on ,nothing else happens ,tried tuning computer on and off no success ,any suggestions what could be the fault.
Jim—07/11/2019
I am also having some problem with led indications …. When i power plug plug into socket 1 led is constatnly lights, 2nd and 3rd leds on and off on and off… 4th led continuesly off.. any one gave suggestions for this problem.. i replace new power suply board also with ifixit support… but here is the problem… 2nd and 3rd on and off on and off…. What does it means any one explain.. please…
Hi all,
my iMac A1224 has the following Situation:
- LED 1: always on
- LED 2 and 3: Flashing every 6 Seconds
- LED 4: always off
Do i need a new Power Supply?
Hi all,
i replaced the power supply and it didnt fix my issue. The mag still does not switch on and boot. The LED behavior is still the same. Then i unplugged the power chord, pressed and hold the power button and plugged it on again. After a release and push again of the power button, the fans run up to full speed. LED 1-3 were constantly on. LED 4 is constantly off and there is no chime… The mac Still does not boot what could this be…?
Hi, SebastianM. Did you repair your Mac? I have the same problem :-(
JAL -
Any update? I,too, am dealing w/ same issues. Disappointing, as I really neeeeeed my Mac! Tried all and even tried using an external display. Another question: With correct adapter&connection, this should work, right, using a smart TV as display??? Just want to see something.
Hey gang-
TL;dr Replace the PRAM battery!
The full story. My 2007 24” iMac Core 2 Extreme- iMac 7,1 A1225 EMC 2134 has been sitting dead for years. Finally decided to see if it was salvageable before recycling it. So I completed this entire tutorial. For me I had LED 1- green and no others lit. When I hit the Power button, LED 1 went dark. Plugged and replugged- no help- all LEDs now dark. Not good.
So I unplugged and figured I’d wait 10 minutes. And since I was in the neighborhood, thought I might as well replace the PRAM battery. I replaced it and then plugged the Mac back in. And Bong! 4 LEDs and full boot up! Yes I know I got off easy- especially since I feared I was looking at a Power Supply replacement at the least. But by all means replace that battery before going any further! The battery simply pries up from its holder as illustrated here (for a different Mac but you get the idea.) iMac Intel 20" EMC 2133 and 2210 PRAM Battery Replacement
PH2 head necessary to remove screw.
airshack - Responder
Mine was as written, a PH1.
tpivo - Responder