Re: MacBook 2011 A1286 power cycle, no chime
Tried flashing the BIOS, tried two different images I found online. It didn't help, the machine acts the same way it did before, so probably not a BIOS issue.
I kinda have a feeling the main symptom I should diagnose is no power in SMC bypass, just a small twitch from the fans, ticking sound from the board.
durchfall
Member
Last Activity: 07-18-2024, 07:35 AM
Joined: 12-14-2022
Location: Prague
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Re: MacBook 2011 A1286 power cycle, no chime
Just did some continuity checks for good measure, all pins of the BIOS chip are connected where they should be.Leave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
CPU vcore stays at 1.15V even without memory, but does beep. Shouldn't that mean the CPU is ok?
BIOS chip area looks fine, no visible corrosion. I did not ty programming the BIOS, don't I need an image with cleared ME region and modified for my serial number? Sorry if this question is dumb, I've only ever flashed BIOS chips on PCs.
Yes, I wrote this into NVRAM nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00. That's all I did as the GPU chip is removed from the board and it did work just...Leave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
I don't see a spike. It just goes from 0 to 5V, then to 0V again when fans stop, 5V when fans start and this repeats. But like I said, not sure if my crappy multimeter could detect a spike. I have a slightly better multimeter at home, can try that on Monday.Leave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
Never mind, I had J5800 unplugged, after plugging it back in I get PP5V_S4_P18V5S5 and 18.5V boost just fine. It doesn't seem to be jumping, but I don't own a good multimeter, so no way to truly check I suppose.Leave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
dellxps15, do you mean PP5V_S4_P18V5S5? That's 0V. We might be onto something.Leave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
Will give that a try and post my results.
Any idea why it doesn't start in SMC bypass mode at all? Fans just twitch once and then you can hear a ticking sound from the board, almost like short circuit protection kicking in.
Could it ba a problem that the GPU and VRAM have been physically removed from the board? But it worked in this state before...
Is there a way of doing NVRAM reset by shorting pads or something? Wanted to try NVRAM reset, but the machine doesn't respond to command option P R.Leave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
reformatt, this is way more than I'm willing to invest in this machine, I got it for free after all. Besides, would it even help me? It worked fine with just an NVRAM variable to switch to IGP, it started doing this after RAM upgrade.Leave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
PLT_RST_CPU_BUF_L is 1.05VLeave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
820-2915-A. PLT_RESET_L is 3.35V.Last edited by durchfall; 01-17-2023, 10:12 AM.Leave a comment:
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Re: MacBook 2011 A1286 power cycle, no chime
No ideas? Is there a mistake in my post that nobody comments? Not enough/too much information? I'd like to fix this thing, but it cost me nothing and I'm not willing to put any money into it, so getting it fixed professionally is not an option. So if I can't fix it myself, in the trash it goes unfortunately.Leave a comment:
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MacBook 2011 A1286 power cycle, no chime
I have a MacBook Pro 15" late 2011, it has a dead GPU and was sent to a repair center for this issue multiple times, the last time the original owner of this machine decided to not fix it anymore. The repair center returned the machine, but they desoldered the GPU and VRAM, it just physically isn't there anymore. The machine did originally work, we'll get to it.
What it does now: does not turn on in SMC bypass mode, the fans just twitch and I can hear a ticking sound from the board, almost like there was a short circuit. But in normal mode it does start, fans spin for about 10 seconds,... -
Re: New Members - please post your introductions here
Hi, I'm just a sysadmin who fixes electronics as a hobby. I'm not an expert and hope to find valuable information in this forum.Leave a comment:
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