Imac 21.5" 3.06ghz no chime/noscreen no led 3 and 4

I have this imac 21.5" 3.06Ghz about 2009/2010
It does not boot, the screen does not light up, there is no chime on boot up.
LED 1 turns on when power is applied,when turn on the power, I get LED 2 to turn on but that is it.
I can hear activity with the cd/dvd as I slipped a disk which I can't get out of it.
LED 3 does not turn on.
I cleaned up the graphic card, reheated applied new heatsink thermal grease etc

I think that I might have a bad logic board, maybe I need to bake that one too?

If you have encountered a problem like this and have found a solution, please let me know

Thanks


Mikercana1

More info

I forgot to mention, after I power on with the switch at the back, only lED1 and 2 are on.
And after a 15 to 30 seconds, the fan go on at full speed?


Mikecana1

Sounds like a serious hardware problem. Could be a bad power supply or logic board problem. Probably time to let an Apple technician trouble shoot it for you.

You seem to have some power getting through so may well be a dicey logic board as chscag suggests. Into the workshop for a quote.

Thanks for your reply
I do not need to take it into an Apple repair or Genius just to tell me that the logic board need to be replaced.

I thought that this was a more in depth repair group.
I am very experienced technologist who repairs just about anything without schematic diagrams. I have just finished in the last hour repaired a Imac 24" power supply, it had blown a fuse and it turns a 150uf 420Vdc capacitor was shorted.
I can do any repairs, surface mount technology is a challenge for most of us older techies.
I can work around surface mount technology, but those BGA technology coming is pure crap when it comes down to users.
Yes manufacturing it makes it easier to manage.
After a few years if there is not good heat transfer or ventilation, it overheats and creates cold joint and there is only 1 way to repair reflow completely the BGA or CPU or whatever it is.


I suspect the logic board indeed, I thought that someone who would have had a similar problem with same symptoms could have led me right to the IC where the fault is.

I do not have schematic diagram, I can figure what IC does what etc.
To try to troubleshoot from pin to pin on the logic without a schematic diagram is extremely difficult.



Thanks again for your feedback but I am looking for deeper help as I am the repair person.
I do this for the challenge, I repair most machine by myself without diagram but logic board troubleshooting is not my thing. I will try to reflow the CPU or some other BGA on that logic and will come back to you.

Thanks again
Mikecana1

I took the logic board apart again.
I was going to reflow some of the ICs, but there is only 1 small BGA ic on it.
While putting back the CPU as I had taken the heatsink apart etc.
I noticed that the pattern on the CPU socket pins was not even, it creates a patterns as all the pins are aligned in the same direction etc.
I looked more closely with the magnifier and 1 to 3 pins in 2 different area were shorted and not aligned properly. I was able to straightened out most of them but 1 of them was broken off (small pad that makes contact with CPU).
I thought that I would try the logic board again.
It is now booting, I have a screen and am able to install OSX etc.

Not sure what this pin does but it does not appear that it is used for most operations.

Mikecana1

It didn't even finished installing OSX, went back into same problem no screen, so chimes, Led 1 and 2 only after a while fans full blast

Seven years later, I wonder whether Mikecana1 came upon anything helpful. Reading the thread, I felt reassured that there are others who expect to be able to repair most equipment themselves. I put myself in this category except where microprocessors are involved, and would never take something elsewhere for repair. What satisfaction would there be in that? (I have recently repaired three inverter welders with logic (control) board faults, not power semiconductor failures, but my Mac repairs have been limited to power supply repairs and rebuilding corroded PCB tracks.)
I have looked every so often into an iMac A1200, which displays very similar behaviour (black screen, no chime, fans full on, front LED full on, 2 (of 4) diagnostic LEDs on, hard drive and optical drive running). I have checked the power supply outputs (all correct) and various mosfets near the graphics card, all with plausible voltages. Also all connecting cables and their sockets. My reading leads me to wonder whether the graphics card is faulty, but on the other hand the fault came on completely suddenly, with perfect behaviour beforehand. Graphics card faults are usually described as gradually developing.
Any ideas? Apart from substitution, is there any way of positively checking a graphics card? And is there any way of procuring a circuit diagram (schematic), perhaps with test points and voltages or waveforms marked? And is the POST process in any way accessible? (I am a 70-year old engineer, and my fluency with electronics does not really extend far into the digital era.)

An A1200 is just on fourteen years oldf Don't put any more money into an old (over six years) computers.

Old iMac

harryb2448 said:

An A1200 is just on fourteen years oldf Don't put any more money into an old (over six years) computers.

Click to expand...

Thank you for the prompt advice. I have always had 10 year old or older Macs, starting in late '90s with a b & w Classic, which was a delight to use. I have lots of old software which serves my purposes well, and which costs nothing. I try to keep out of the race between powerful new software and their need for powerful new computers, but I do move on keeping a decade or so behind the times. For some years now I have been on a 2006 20" iMac, 32 bit, but I often could do with a 24" screen. Hence efforts with the A1200, but additionally offering 64bit, which would help on internet and also enable me to use a more recent Illustrator and Photoshop which I have waiting in the wings.
Don't worry, I will not spend more than the occasional £1 or 2 on repairs; I collect plenty of scrapped equipment, from which I salvage components. One of the welders, a top-end model 10 years ago, bought cheaply (ebay) as not working, came back to life when I replaced an invisibly cracked SMD capacitor timing an SMPS for the logic board, and I know well how small a repair can sometimes produce a large benefit. But time is required for diagnosing, which usually means working out how the thing is supposed to operate. Hence my questions about the iMac fault. Other people spend time on crossword puzzles; I enjoy my choice of puzzle when there is time in the evening.
Thanks again, but has anyone the necessary technical knowledge?

I have a similar situation with my late 2009 21", 1Tb HDD, iMac that I loved and Apple quit updating it past OS High Sierra Ver. 10.13.6. After I got my new 27" I wanted to erase my old one and reinstall it to factory settings using Disk Utility. Everything went well trying to follow the instructions received. Went to reinstall by restarting but! no can do, when I turned the power on the install line takes forever to load (around and hour) after it completely finishes nothing happens, and the top of my monitor gets extremely hot. Have I missed a step or not entered a key sequence before starting to reload? I have tried this several times with the same results. Have I lost it forever? Thanks for any help on this matter.

Postoak said:

I have a similar situation with my late 2009 21", 1Tb HDD, iMac that I loved and Apple quit updating it past OS High Sierra Ver. 10.13.6. After I got my new 27" I wanted to erase my old one and reinstall it to factory settings using Disk Utility. Everything went well trying to follow the instructions received. Went to reinstall by restarting but! no can do, when I turned the power on the install line takes forever to load (around and hour) after it completely finishes nothing happens, and the top of my monitor gets extremely hot. Have I missed a step or not entered a key sequence before starting to reload? I have tried this several times with the same results. Have I lost it forever? Thanks for any help on this matter.

Click to expand...

Are you going into Recovery partition, on the 2009 iMac? Or was that erased when you wiped the drive? Do you have a bootable macOS High Sierra USB installer or the original install disc that came with the iMac?

I have found my OS X Snow Leopard install DVD, the grey iMac OS X install DVD, and a grey iMac Applications Install DVD. I must have erased everything else off the disk. If any of this will help let me know but I won't be Able to work on the old computer until tomorrow, so no hurry at all. Thanks for replying ferrarr. I'm not nearly as smart as the other person on this stuff.

It is disappointing and frustrating when something which has worked perfectly suddenly becomes useless, especially if you think that only a very minor trouble might be responsible. But in your case the 'very hot' would make me worry. Nothing you can do with software should be able to make it very hot if the hardware is all in order. I would begin by suspecting that the cooling fans are less effective than they should be, perhaps an accumulation of dust, and something about the wiping and re-installing process got the computer working hard (processor very busy) without any rest (the hour-long activity), and more in need of the cooling equipment than it had been in your regular use. What to do now? I suppose open it all up and clean it thoroughly (compressed air through heat exchangers etc). If before attempting installation you check the hard drive with disc utility does it say that the disc is good? Even if it does you could perhaps temporarily fit a spare smaller old hard drive and try installing again.
At least your computer works well enough to allow you to get started on the installation process, so I think it is likely that the hardware is undamaged.
Good luck

Very discouraging! At least I got more of my moneys worth out of it than I will this new 27" I just bought. Thanks for the suggestions anyway AndrewDun.

Don't be too discouraged! Is it the prospect of opening it up which worries you? It is a rather fiddly process, but not particularly difficult. But instead, what about first just making sure the hard drive is good, using Disc Utility and any other disc tools you can find. If the drive is beyond reproach what about trying loading the earliest OS the computer will take. If you manage to get something loaded, then there are tools you can download which read the various temperature monitors and you can find out what part is too hot (e.g. hard drive, or perhaps main processor). Then, you would at least know that everything is functional, and you might feel more inspired to dismantle and clean the innards if that is a problem.
One other thought: If you can lay your hands on an external hard drive you could try loading an OS on that rather than on the computer's internal drive and see what happens.
Good luck, Andrew.