Help - iMac wont boot.

snollup

Trying to start my iMac and am getting a white screen with apple logo & and status bar. This stays on this screen for about a minute. Status bar makes it about 1\4 of the way across and then the machine shuts down. Is there anything I can do to force this to start or has the hard drive failed?

Thanks.

muggyog

Can you start it in single user mode or what happens if you hold the 'alt' key on power up? Sounds like a firmware update loop.

snollup

Ran disk utility, was unable to repair so had to reformat. In the middle of reinstalling os and then it's back to backup! Am hoping the disk is ok as after I reformatted I was able to verify the disk ok. Hears hoping!

Greentree_uk

I'd say you'll need to replace that hard drive. seen this a few times now and the hdd always needed replacing.

snollup

Greentree_uk wrote: »

I'd say you'll need to replace that hard drive. seen this a few times now and the hdd always needed replacing.

Any idea of what a new HD will cost for a 2008 intel iMac?

barryj

snollup wrote: »

Any idea of what a new HD will cost for a 2008 intel iMac?

50-100 euro depending on size/brand you want. Bit more if you want one of the new-fangled 3TB models.

- barry

snollup

barryj wrote: »

50-100 euro depending on size/brand you want. Bit more if you want one of the new-fangled 3TB models.

- barry

cool, that's not as bad as I thought.

Ranicand

snollup wrote: »

cool, that's not as bad as I thought.

For me the most important thing on a computer drive is the photos they can not be replaced I hope you had them backed up?

akaspike

Greentree_uk wrote: »

I'd say you'll need to replace that hard drive. seen this a few times now and the hdd always needed replacing.

This happened myself a few weeks ago, the Imac was 2 weeks old. The repair took a week but was cover under warranty. Make sure you back up asap

Liameter

Ranicand wrote: »

For me the most important thing on a computer drive is the photos they can not be replaced I hope you had them backed up?

Most people have no idea that a backup drive is an essential part of any computer system. Until they lose their precious photos!
http://www.glodark.com/computer.htm

snollup

So, ended up bring m iMac into the lovely people in Compub (Swords) and the installed a new 1tb hard drive for me. Brought the machine home and started to put all my data back on from my externel hard drive that I back up to. All good so far....

When playing songs in iTunes the machine suddenly stops playing the media & the machine seems to go to sleep. Harddrive & fans see to go quite & screen goes black. When you hit the space bar that machine comes back to life.

Then I notice that the machine takes an age to shutdown & restart. Also the top & back of the iMac seem to be very hot to touch.

So I ran the hardware test that is available on the original discs that came with the machine and the following error was returned 4sns/1/40000000: Tp OP-95.546.

Am waiting on the extended tent to finish but I am a little concerned. When I googled the error code results seemed to point to the logic board.

Anyone ever seen this before.

Thanks.

Greentree_uk

sounds like another excellent repair from CompuB... but perhaps you haven't run the software updates yet?

snollup

Greentree_uk wrote: »

sounds like another excellent repair from CompuB... but perhaps you haven't run the software updates yet?

No, in software fully up-to-date.

snollup

After a little more digging around it looks like there's a chance that resetting the PRAM and NVRAM may cure it. Will try this tonight.

If not it looks like it may need a new logic board. Any idea of the cos of a new logic board for a 2007 24" iMac (Intel).

barryj

snollup wrote: »

After a little more digging around it looks like there's a chance that resetting the PRAM and NVRAM may cure it. Will try this tonight.

If not it looks like it may need a new logic board. Any idea of the cos of a new logic board for a 2007 24" iMac (Intel).

You can get an idea of Apple part costs on this website.

http://www.applemacparts.co.uk/

If it's a logic board for that age machine, you might want to start considering a new machine. You'd probably pick up a refurb 21.5" imac for not much more than the cost of the repair. Logic boards are expensive.

- barry

eco2live

There is a temp sensor on the HD that goes to the logic board. If they did not put back in the same model hard drive you can have problems.

You can check this yourself by downloading istat and looking at the HD fan and temp. If the hard drive fan starts to go past 2000rpm while the machine is not doing much then that is the problem.

Have you noticed that the imac is nosier then usual because of the fans?

snollup

barryj wrote: »

You can get an idea of Apple part costs on this website.

http://www.applemacparts.co.uk/

If it's a logic board for that age machine, you might want to start considering a new machine. You'd probably pick up a refurb 21.5" imac for not much more than the cost of the repair. Logic boards are expensive.

- barry

Let's hope logic board is not the problem then!

eco2live wrote: »

There is a temp sensor on the HD that goes to the logic board. If they did not put back in the same model hard drive you can have problems.

You can check this yourself by downloading istat and looking at the HD fan and temp. If the hard drive fan starts to go past 2000rpm while the machine is not doing much then that is the problem.

Have you noticed that the imac is nosier then usual because of the fans?

Will check this when I get home tonight.

snollup

I've now reset the PRAM and re-run the testing disc & it passed. Downloaded istat and CPU fan is running at 1199rpm. My problem now is the time it's taking to start, well over a minute.

Any ideas?

Liameter

Surely the fan WON'T start until the CPU warms up?

snollup

Liameter wrote: »

Surely the fan WON'T start until the CPU warms up?

Not entirely sure what you mean here. However the machine has been on for an hour or so and HD fan still spinning at 1199rpm.

Edit: Just noticed now that CPU fan is spinning at 3271rpm. Is that normal? Seems very high compared to the HD fan? Not particularly noisy though.

muggyog

I wouldn't get overly concerned about fan speed, its temperatures that are the real issue. If your Mac gets too hot the thermal cutout kicks in and shuts the machine down. Have you done a sbin/fsck -f in single user mode on the new drive? When you say a delay in starting, do you mean how long it takes to come to login screen? If so open your Console app and check 'all messages' log. Entries are time stamped so you will get an indication of whats wrong.

Liameter

I was referring to your last statement about the CPU fan taking time to start.

...CPU fan is running at 1199rpm. My problem now is the time it's taking to start...

snollup

muggyog wrote: »

I wouldn't get overly concerned about fan speed, its temperatures that are the real issue. If your Mac gets too hot the thermal cutout kicks in and shuts the machine down. Have you done a sbin/fsck -f in single user mode on the new drive? When you say a delay in starting, do you mean how long it takes to come to login screen? If so open your Console app and check 'all messages' log. Entries are time stamped so you will get an indication of whats wrong.

First off, thanks all for you help with this. Am learning lots about the workings of my iMac.

@ muggyou: Regarding the startup times. I am referring to the time it is taking to bring uo the logon screen. About 1min 30secs.

I would not have the knowledge to run the sbin command I'm afraid. However, it is a brand new HD if that counts for anything.

Again with the log files, I have taken a look & nothing jumps out but I'm no expert so am probably missing something.

The temperature of the machine is of major concern. Below are the readings from iStat:

HD: 52, CPU: 44: Airport Card: 57, Ambient: 22, GPU: 58, GPU Diode: 60, GPU Heatsink: 58, HD Bay: 55. (all in degrees Celsius).

muggyog

Single user mode = Press & hold 'command' (apple) and 'S' keys on power up. When the text stops scrolling, type sbin/fsck -f and wait. See if it fixes anything (fsck=file system check). Type 'logout' to bring you to Mac login window ( or restart ).

Paste the part of your log from startup to when it finishes loading all the drivers and turns on power management ( i.e. the problem area = 1&1/2 mins ).

You might also run the Activity monitor app and see what is running because obviously overactivity will cause overheating. See is anything eating CPU resources.

snollup

muggyog wrote: »

Single user mode = Press & hold 'command' (apple) and 'S' keys on power up. When the text stops scrolling, type sbin/fsck -f and wait. See if it fixes anything (fsck=file system check). Type 'logout' to bring you to Mac login window ( or restart ).

Paste the part of your log from startup to when it finishes loading all the drivers and turns on power management ( i.e. the problem area = 1&1/2 mins ).

You might also run the Activity monitor app and see what is running because obviously overactivity will cause overheating. See is anything eating CPU resources.

Thanks for this, will try tonight.

snollup

Can anyone tell me what temperature the CPU & HD should be at when running? The back of the machine seems very hot to the touch.

Thanks.

Greentree_uk

why don't you take it back to CompuB and complain it isn't working properly since you got it back?

snollup

Greentree_uk wrote: »

why don't you take it back to CompuB and complain it isn't working properly since you got it back?

Plan to on Monday (if there open).