A1278 Random crashes 820-2530

[cruiser_]

Hi,
I'm having a go at this Macbook pro mid 2009 laptop I've got for chips bare bones. It's a pretty interesting case...Fresh thermal paste, clean the fan, inserted HD, memory sticks, clean OS install. CPU temps 70-100C.

Laptop seems to be working ok for a number of days. I can run benchmarks all day long, browse the internet etc. I reboot it every now and then (bear in mind, still keeping it pretty hot). At one of these times - it won't boot to OS.

Command V shows some random kernel panics (no mention of GPU).
HD filesystem gets corrupt - to a point where fsck cannot fix it (on another macos). While in this condition it can even crash reboot on OS installer.

After it cools down I can reinstall the OS and the story repeats itself. Regardless whether its running off of battery or AC.

Memtest86 can run for hours, no memory issues. As mentioned before, benchmarks can run for hours, no issues, no glitches, no reboots.

What gives?

Did some measurements and I am wondering if it is normal for the PPVCORE_S0 to fluctuate?
Any idea what could be causing this strange behavior?

PPVCORE_S0_CPU - starts at 0,994V ? full boot down to 0.90V then to 0.75V
PPVCORE_S0_MCP - 1,005V (C7565)
PP1V05_S0 - 1,068V
PP1V1R1V05_S5 - 1,061V
PPBUS_G3H_CPU_ISNS - 12,57V
PP1V05_S0 - 1,068V
PP1V5_S0 - 1,492V
PP3V42_G3H - 3,40V - resistance to ground (black lead) - 53,3k (C4650)
PPVIN_S5_IMVP6_VIN - 12,58V
PPV5_S0 - 5,01V

[mon2]

Re: A1278 Random crashes 820-2530

Hi. Yes, believe that the logic boards we have repaired are with the same fault as yours. The latest one, the client was complaining that she could barely touch the enclosure of the macbook from too much heat. She felt it would catch fire and stored it in her bathtub (without water of course) for safety.

After the referenced tantalum cap - cool as a whistle and no more flaky results / random crashes. See more for details.

https://store.rossmanngroup.com/d3-c...0-1-piece.html


Review this video - we have repaired a few of these logic boards by using the recommended larger size tantalum cap:

https://youtu.be/NfY6vTQthiE

For future readers, we used the following part from Arrow with success:

EEFGX0E331R PANASONIC
Cap Aluminum Polymer 330uF 2.5VDC 20% (7.3 X 4.3)

Update: Here is a great replacement for this defective cap (in stock @ Arrow):

https://www.arrow.com/en/products/ee...31r6/panasonic

rated @ 7500mA

[cruiser_]

Re: A1278 Random crashes 820-2530

hi @mon2,
I read about this issue and watched Louises (and others) video too. Thought this was an issue on slightly newer boards though?

"C7771 is a tantalum cap that you read 0.331v on instead of 1.05v on, this might help you. Most of the time, it is a bad capacitor. It is too small and the single small tantalum cap is not fit for this circuit, it dies, and causes machine to not turn on when it gets cold. You can confirm this cap is bad with a small bit of heat - it will work again until it cools down."

It seems in my case things work grand when cold and I am getting a steady 1.05V there?

[piernov]

Re: A1278 Random crashes 820-2530

A1278 != A1286

https://logi.wiki/index.php/A1286/A1297_Common_Issues

HDD & HDD cable replaced?

[cruiser_]

Re: A1278 Random crashes 820-2530

hi piernov. Different HDD/SSD tried and yes, the cable was replaced according to previous owner.

What's puzzling me is that it happens over such a long period of time. Perhaps some idea what to 'stress' more?
I am thinking some massive disk benchmarks running over and over again - but I am not aware of one that would actually verify what's being read back from disk is what had been written to it.

[cruiser_]

Re: A1278 Random crashes 820-2530

hmm... I disconnected the disk and DVD drive, now I'm in a state where the OS installer boots, keeps loading and restarts at 'examining volumes' or earlier. suffice to say when it cools down, things normalize.
is it 'normal' for the board itself to get to a 50/60 degrees Celsius mark?

[mon2]

Re: A1278 Random crashes 820-2530

To me, it sounds high. The heatsink is mounted properly ? Are you using thermal paste or thermal pads under the heatsink ? We have used the T-Global brad of thermal pads - bought from Digikey. We met T-Global (Taiwan) at past trade fairs in Hong Kong and they claimed to be the leaders in the field. A bit more cost but we are pleased with the results on reworking iMAC cards and CPUs with their products.

[macattack600]

Re: A1278 Random crashes 820-2530

Memtest is not all that great I've used it and still had to swap memory try once more seating 1 at time and different sticks too.


Does the MCP feel burning hot? The installer loading over and over really does not sound good.


Run ASD and see what that says

[cruiser_]

Re: A1278 Random crashes 820-2530

@mon2 i replaced the paste on MCP & CPU with arctic cooling one, also cleaned the vents etc.

@macattack600 - great suggestion, that's exactly what I have started doing since yesterday. I have been testing it with just one stick in.

Installed BigSur with opencore, now running f3 read/f3 write and memtester at the same time repeatedly, so far so good with just one stick in.
Cannot run ASD (don't know how to get there with opencore patched OS...'D' makes no difference in the boot process). Is there another way of opening it?t

I've been using memtest86 successfuly on PCs and it never failed me in finding bad RAM. Is this different on MACs?

[cruiser_]

Re: A1278 Random crashes 820-2530

A quick update.. after a few weeks of stable operation with one stick, today the macbook did not reboot (repeatable kernel panic).

Booting off memtest86 gets stuck at 'getting memory size' or does not show anything at all. tried two memory sticks at this point with little difference. disk and dvd disconnected.

I've gone through the vcore voltages, MCP voltages, SATA voltages etc. all look nice and steady.

What gives? :\