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A1311 820-3126 iMac with frequent wait cursor SBBOD

Outofwhack

Outofwhack

Member
A customer has sent me there 2011 A1311 iMac for memory upgrade and SSD upgrade in the hope of getting some use out of it.
But its plagued with the spinning beach ball of death (SBBOD) after virtually every user interaction and it lasts for several minutes.
Ive tried two different MacOS versions - no change.

Ive now realised my batch of rather expensive laptop schematics has no iMac boards afaik.
So I have really no resources to help with iMacs - no schematics, no diagnostic software.

Can anyone point me to any diagnostics tools or technique of determining what is causing this behaviour and solving it?

It has AMD Radeon HD 6750M 512MB graphics and once in a blue moon I have out of the corner of my eye seen a flash of the top quarter of the screen.
Can the graphics chip be disabled to use an onboard graphics chip to see if it causing it or am I barking up the wrong tree?
 
2informaticos

2informaticos

Administrator
Staff member
You cannot disable GPU.
As a quick test, you can heat it to 180-200 degrees for 15-20s.

May get more information runing corresponding EFI ASD test.
 
Outofwhack

Outofwhack

Member
Thanks again 2informaticos,

How do I get hold of the corresponding EFI ASD test?

In case this reveals a particular area of trouble are there schematics available for iMacs so I could locate the device?

Is there a way to determine why the OS is displaying the wait cursor? core dump?
 
Outofwhack

Outofwhack

Member
Ive installed a new 1TB SSD and installed High Sierra but still incessant SBBOD.
So it looks like I need to get hold of ASD 3S145. How do I get hold of it? Searches just take me to what look like dodgy sites.
 
Outofwhack

Outofwhack

Member
Many thanks for the diagnostics - HD temp issue - Im looking at the numerous different suggestions for hacking the ribbon cable on this no-sensor iMac. that Ive added an Adata SSD to.
 
2informaticos

2informaticos

Administrator
Staff member
Just short to ground the dedicated pin on the SSD's SATA connector.

You should post 820-xxxx code, when you start a thread!
 
Outofwhack

Outofwhack

Member
Ive shorted to ground pin 7 to GND (pin 1) on a SATA extension cable and it has had the desired effect of getting rid of the high temperature indication :)

But attempts at cloning to the drive using Disk Utility and carbon copy cloner results in complaints of S.M.A.R.T status errors.
Should I have snipped line 7 beyond the grounding so the SSD doesn't get side effects from having its pin grounded?
 
2informaticos

2informaticos

Administrator
Staff member
I suppose you was looking some schematic; no idea if from SATA stantard layout, or some iMac.
Unfortunately, your board model is still kept in secret.
 
Outofwhack

Outofwhack

Member
Yes sorry Ive updated the title now. I have managed to work out its a 820-3126 logic board on this iMac although only by comparing its layout with what 820 logic boards sell as a logic board for an A1311 - I haven't removed the board yet and I think the actual board number must be on the hidden side. Ive just had success cloning the old spinning HDD to an SSD using CloneZilla on a PC avoiding any S.M.A.R.T errors.

So I'm quite happy at the moment and just wondering if the grounding of the pin on the ADATA SU630 was upsetting operations and should be left to float.
I am about to put that SSD back in the iMac and wonder if I will see more S.M.A.R.T errors reported.
 
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Outofwhack

Outofwhack

Member
Thats a good question - how I came to the conclusion to join pin1 to pin7 which now looks like joining two grounds together.

Before I figure out why I did this do you mind if I ask another question on logistics....

With the LCD screen removed from the iMac will video be available via the Thunderbolt socket?
 
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Outofwhack

Outofwhack

Member
I don't understand what you just said. I am wondering whether video is output via thunderbolt when the logic board realises the LCD panel is not connected.
 
2informaticos

2informaticos

Administrator
Staff member
You don't need to have internal LCD connected, to get external video.
If no internal LCD is detected, external video is forced of course.
 
Outofwhack

Outofwhack

Member
Thanks for confirming that! Then I have two thunderbolt to HDMI leads that don't work - do they need to be genuine Apple leads I wonder....
 
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