Mid 2008 iMac Boot issue

[wolrabn]

Hi All

wondered if anyone can shed a light on this.

iMac mid 08 recently went capput. Was working fine then restarted itself suddenly. It did that a couple of times so I ran through Disk Utility and repaired permissions etc all seemed ok and passed checks, upgraded to El Capitan latest revision and left it a bit. It then restarted itself again only this time failed to boot.

Its now stuck on permanent white screen post chime.

Tried PRAM reset - which results in the mac restarting but again sits on white screen.
No other keyboard functions appear to work, cannot boot to install DVD, Hardware check etc.
Eject does not work so cannot remove install media. Right click does not eject either.

I have removed HDD and booted with NO HDD present - same issue.
I have removed HDD and replaced with new HDD - same issue
I have removed RAM individually, when removing both I receive beeps indicating no RAM.
I have disconnected all devices other than power lead again with no success.
I have unplugged completely for at least 15 mins to reset SMC.

Fans spin fine, green LED light on board when connecting to power.

Any suggestions to resolve? I realise this is an old machine however up until now its been a rock so I'm hoping there's still life in the old dog yet.

 

[keysofanxiety]

You've tried pretty much everything.

What about through an external monitor? Does it show the same thing (white screen) or does the external monitor not even flash into life?

 

[wolrabn]

You've tried pretty much everything.

What about through an external monitor? Does it show the same thing (white screen) or does the external monitor not even flash into life?

hmm... must admit I didn't try that one. luckily I have output adapter. As a test will connect later on and will post feedback

 

[wolrabn]

hmm... must admit I didn't try that one. luckily I have output adapter. As a test will connect later on and will post feedback

Nope... No luck :-( any other ideas?

 

[nambuccaheadsau]

When you do the SMC reset, did you remove the plug from the rear of the iMac to reset it? Sometimes unplugging from mains is not enough.

Also any chance you are using a surge protector? After that all is pretty glum!

 

[wolrabn]

When you do the SMC reset, did you remove the plug from the rear of the iMac to reset it? Sometimes unplugging from mains is not enough.

Also any chance you are using a surge protector? After that all is pretty glum!

ITS ALIVE!!!

So after a lot of digging online and suggestions here I decided to create a USB bootable disk instead of using DVD. Disconnected both DVD drive + Hard Drive, Mounted original Leopard USB Boot and booted holding C and the miracle that is the Apple logo appeared.

At this point I then shut down and reinserted the original hard drive and booted. Bizarrely after its white screen sabbatical it seems to have given it the shunt it needed and has booted.

I am currently typing on it. Going to reconnect the optical drive back in tomorrow and see if this was possibly the weird cause of issues all along.

Anyway, thanks for your help/suggestions. If anyone has a similar issue I would suggest trying to boot from USB minus both optical + HDD inserted.