⟐ Commented April 04, 2026 at 5:38 MST

I have everything you need (or so I think) to use my imac lcd panel (panel LM240WU2 ( SL) ( B4 ) ) as a monitor for other pc

http://i62.tinypic.com/112e876.jpg

http://i61.tinypic.com/2mwxct2.jpg

also I connect the cable from the inverter to the lcd

this http://i59.tinypic.com/f10dts.jpg to http://i57.tinypic.com/f2itxd.jpg

Connect the power cord from the iMac ( white ) energy to the panel. and I connect the power adapter to the board vga 12V 2A

but does not work , connect via a PC to give vga video signal and does not work

do I wrong ?

Help please :(

⟐ Answered April 02, 2026 at 23:00 MST

⟐ Answer accepted March 31, 2026 at 12:30 MST

I got horizontal lines over the display! During the warranty period they replaced the board ( it blacked out ) and now this is happening. They refused to replace the device saying out of warranty and asked to replace it :-|. They were not even sure that changing the display will fix the issue. I am hesitant to replace the screen as I am better off to buy a new one rather keep repairing the faulty product.

Is there any way to fix it?

Tried
- Reinstall the OS
- External Display = Works fine
- Reseating those 3 cables

Lines kind of flickers, may be some lose cables?

Please help

⟐ Answered March 29, 2026 at 1:03 MST

• One big 12 pin molex connector connected to the logic board.
• One small 2 pin connector connected to the power button.
• One small 7 pin connector, connected to the logic board via a flat cable.

The big 12 pin molex connector is apparently the 12V rail. It's also confirmed by the schematic.

The 2 pin connector for power button is probably a passthrough to the logic button. The PSU usually needs a PS_ON pin to be pulled to the ground to keep on, if it's like an ATX PSU.

The 7 pin connector probably has that PS_ON pin, along with some other pins. I'm trying to figure out their functions. According to the schematic, they are:

1. PWR_BTN_R
2. GND
3. SMC_ACDC_ID_R
4. TSNS_ACDC_N
5. TSNS_ACDC_P
6. GND
7. BURSTMODE_EN_R_L

So, it confirms my suspicion about the power button. Pin 1 must be the power button pass-through. I looked up burst mode, which I probably don't need to worry about. But I'm unclear about the rest 3:

• SMC_ACDC_ID_R
• TSNS_ACDC (Positive and Negative)

Can someone shed some light on them?

P.S. does anyone know what kind of connector it is? I hate cutting the original cable. Worst case, I can solder wires to the PCB but it's kinda hard to do with the connector in place.

Schematic:

Connector:

⟐ Commented March 26, 2026 at 17:18 MST

My iMac is a 2019 5K iMac 27in with an Intel i9 processor at 3.6GHz. (iMac19,1 - EMC 3194)

After putting Arctic Silver MX-6 on the heat sink and reassembling the Mac, when I start it up it is very slow to boot and is very sluggish. The fan is running at full speed.

I have reset the SMC and the PRAM several times, and have checked and re-checked all the cable connections to no avail.

It is running Sequoia 15.7.4.

Has anyone got any suggestions for a fix?

⟐ Answered March 25, 2026 at 15:53 MST

⟐ Commented March 25, 2026 at 6:10 MST

⟐ Commented March 24, 2026 at 12:44 MST

Nothing happens when I press the power button other than a small hum.

Removing the display gives me access to the LEDs showing 1 and 2 are lit but nothing from 3 or 4.

The 2600 is a known working chip and the 2500s still works fine in the board.

Please help.

⟐ Answered March 24, 2026 at 10:54 MST

TLDR: T2 / PCH related kernel panic if CPU is hot for a long time, boots only after I let it cool down. No kernel panic during normal/light use. Possibly a faulty component on the motherboard that has a bad connection? Possible fix if opened?

EDIT: More tests in the comments

Long version:

I obtained a faulty 2020 iMac 5K with an i7-10700K and 5500XT to be used as a DIY 5K project base. The ad said that the GPU is faulty, it randomly restarts but during normal use, no problem.

The screen is the most important for me (only slight pink hue around the edge, no problem), I did not really care about the issue but here is what I discovered and it made me more interested in fixing the issue.

I benchmarked the GPU using Heaven Benchmark for 1-2 hours running at max fan speed, the GPU was at 80-90 degrees and it did not restart.

Then I benchmarked the CPU using Cinebench, survived 10 minute single-core but crashed 2-3 seconds after starting multi-core. Later when it cooled down, I tested the multi-core again and it lasted a lot longer but not 10 minutes.

When it restarts, sometimes it crashes on boot but mostly it gets to the login screen, can stay there for hours but after entering my password and it would start loading everything, it crashes until I let it cool down so it has a thermal headroom or something. Macs Fan Control turns up the fan speed immediately after login but still not early enough, I also turned off Intel Turbo Boost to decrease the temp generation.

The kernel panic logs (when present) show T2 / PCH / SEP related crashes (BAD MAGIC, x86 global reset detected - CORE 0 is the one that panicked / void AppleEmbeddedPCIeUpLinkMgmt::_linkInterruptAction(IOInterruptEventSource *, int): A link timeout has been seen after 650000 microseconds and 49999 iterations - CORE 0 is the one that panicked

But the weird thing is that I have been using this thing everyday for basic tasks, logging in, sleeping, passwd auth, everything seems to be working as usual. I guess normal tasks use the T2 as well but it does not heat up that much maybe?

What I'm planning to do in the coming weeks is to open it up, check visual defects on the motherboard, get an LGA1200 PC motherboard to test if the CPU is okay or not.

This whole issue seems to be only happening when the CPU is over 75-80 degrees for longer period of time when the nearby components are also heated up, I suspect a faulty connection somewhere that is when hot, not connecting correctly. Maybe the T2 chip's connection is bad or something?

What do you think, what would be the best steps to troubleshoot this issue? Is there a tool that only stress tests the T2 chip and not the CPU? Maybe a feature in macOS that really stresses that?

Thank you in advance!

⟐ Commented March 24, 2026 at 8:41 MST

⟐ Answered March 24, 2026 at 7:40 MST

⟐ Commented March 20, 2026 at 5:16 MST

But while trying to close the iMac screen, all adhesives lined up, I connected the display's power cable and ribbon cable. Mistakenly, I lifted the display while trying to align bottom and ouch....the ribbon cable (vsync cable??) pulled out from its connector argh.....

I connected it back and closed the iMac. When I powered up there was a green vertical line (which was gone after a min) and the gray/black thick stripe about 1.5inch wide. This stripe stays all the time from boot to shutdown.

Tried SMC reset, PRAM reset... no luck.

I doubt the ribbon cable damage (is it vsync cable)...now I'm skeptical to reopen to play around without knowing what could be the issue.

Many questions on my mind....did I damage the display? Is the ribbon cable replaceable (I tried googling for spare part couldn't find a proper lead)?

Any help would be much appreciated thanks.

Finally fixed the expensive mistake :)

Had a local shop fix my system in Dubai

Also the iFixit adhesive strips and the removal tool are a must have!

[linked product missing or disabled: IF173-005]

⟐ Answered March 19, 2026 at 12:01 MST

⟐ Commented March 17, 2026 at 14:09 MST

This is my cousin's iMac. She told me she was using it one day and heard a loud pop and then the iMac lost power and it would not turn on any more. I was unsure if the problem might be the very expensive AC adapter or the computer itself so I took the computer to a Mac store in a nearby town. They tried plugging a known good AC adapter in to the iMac but it still did not turn on so it seems the iMac is the problem.

Today I took the screen off to have a look at the circuit boards inside to check if there might be something obviously damaged like an exploded capacitor. So far I've seen only one side of the two boards but I don't see anything wrong yet.

I read in another thread that there may be some diagnostic LEDs on the board which may give me some hints about the status of the computer. I tried plugging in the AC adapter, with the screen off, but I did not see any LEDs light up. I did notice there is a tiny button on the main circuit board and it may have three tiny LEDs next to it. I thought about pressing the button to see what would happen but I'd rather not do that unless I know exactly what that button is supposed to do. What does it do?

Should I proceed to disconnect the cables from the main circuit board and take it out to have a look at the backside?

⟐ Edited March 16, 2026 at 21:47 MST

Looking at this product here, it does not say if it causes the issues or not. Just to update mac for the firmware.

What's the performance gain if I would already have a SSD instead of a HDD?

What is so special about the Apple blade SSDs that others have problems waking from sleep?

⟐ Answered March 16, 2026 at 1:38 MST

Than I installed the OS X Leopard and connected with the time machine to restore the backup files.

This took multiple hours and this morning I got the message restore complete please reboot. which I did but now after rebooting the gray screen turns to a dark gray screen and the message in a black box appears "Restart computer by holding down the button..." Unfortunately everytime I do this I end up with the same screen.

I run disk utilities and repair disk, but can't detect any problems.

⟐ Commented March 11, 2026 at 12:57 MST

⟐ Commented March 10, 2026 at 20:40 MST

I want to update my Mac pro a little

now there is an opportunity to buy DDR3 2400 (as in the picture)

Can you please tell me if I can use such a memory? (factory memory has a lower frequency)

Here is the label

⟐ Answered March 04, 2026 at 7:29 MST

Do I have to change the power supply as well?

⟐ Commented February 27, 2026 at 6:04 MST