Re: Macbook Pro 820-00840-A 20V but not turning on
Hello, thank you.
My symptom actually ended up changing. It may have ended up happening after changing U7000, I can't remember if I measured PPBUS_G3H after replacing this IC or if I only checked with the ammeter for activity after replacement. Either way I now have a steady 13V on PPBUS_G3H and the current consumption on the ammeter goes between 0mA and 10mA. Still no power though and I do not measure activity on any other voltage rail.
As for history, I don't know much. There is no sign of liquid...
TVMexicana
Member
Last Activity: 07-20-2020, 09:40 PM
Joined: 03-30-2019
Location: Chicago
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Macbook Pro 820-00840-A 20V but not turning on
Hello all,
I'm trying to figure out the issue with this macbook pro. It will not turn on or charge. When I plug in the charger using my USB-C ammeter I can see the voltage go from 5V to 11.7V to 20V but there is no current consumption. PP3V3_G3H is present. PPBUS_G3H attempts to go on but goes back off after only a very brief second. I do not see any short on PPBUS_G3H nor do I see any other obvious shorts on the other power rails that come after it. I removed U7650 to isolate all power rails that are created from it and I still get the same symptom. I also tried to replace U7000... -
Lenovo G510 black screen
Hello all,
I'm trying to figure out the issue with this Lenovo. Symptom is the computer will power on and the fan will spin but nothing ever really happens. When it turns on I can see that the LCD comes alive except for the backlight, the LCD is not displaying any logos or any bios screen, simply seems to go black as if all the pixels activate. When hooked up to an external monitor through HDMI nothing appears on screen. I can feel that the CPU gets a bit hot as if there is activity. All power rails seem to be okay during my very brief look around for the issue. I have attempted... -
Re: Alienware 15 not charging
Great tip!
However it seems both new and old batteries are the same. I ran diagnostics with the old battery whith basically the same results. Old battery is only at 65% health but should still be able to charge fine.
The bios shows charger as the correct 180W charger.Leave a comment:
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Re: Alienware 15 not charging
Hello, the battery was replaced and it made no difference. Here is the results from the diagnostic....Leave a comment:
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Re: Alienware 15 not charging
I'm not sure of the exact model of the laptop besides "alienware 15", the label at the bottom has faded away. Motherboard is LA-B751P and the schematic is attached below....Leave a comment:
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Alienware 15 not charging
Hello all,
I have an Alienware 15 laptop that is not charging the battery. When I plug in the adapter it shows as charging sometimes and sometimes not, but always recognizes the adapter is being used. Either way it never actually charges. When it does show up as charging it'll say something like "5 minutes remaining" even though the battery is only at 1% at this point. Changing the battery was already attrempted and this made no difference.
When I measure the voltage at the battery I notice when I plug in the adapter that the voltage briefly goes up to 18V...Last edited by TVMexicana; 11-11-2019, 06:37 PM. -
Re: Lenovo Yoga 710-11ISK Only White Light
Anyone?Leave a comment:
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Re: Lenovo Yoga 710-11ISK Only White Light
How can I flash the bios this way? Have only done it before with a booting computer. Also checked for available bios chips but none available for this computer. Anyway to clear cmos on this board?Last edited by TVMexicana; 06-13-2019, 09:42 AM.Leave a comment:
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Re: Lenovo Yoga 710-11ISK Only White Light
Forgot to mention that on those two coils PL601 I get the same resistance to ground as if they are both supposed to be feeding into the CPU. Is there a schematic out there for this thing?Last edited by TVMexicana; 06-12-2019, 10:05 PM.Leave a comment:
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Lenovo Yoga 710-11ISK Only White Light
Hello all,
I have this Lenovo Yoga 710 which does nothing but give a blinking orange charger light and a white power light. The screen does not turn on, I don't see anything on the LCD even when shining a light and when i hit the caps lock button I get no light there either.
I tried checking voltages on the motherboard and the only thing that seems a little odd to me is that next to the CPU there are two large coils PL601 and PL603 of which PL601 produces 0.86V and PL603 produces nothing.
While the computer is on the CPU does get hot as if something... -
Re: HP Touchsmart 310 DA0NZ2MB6F0 No Boot
Techtiger that was the fix! Thank you. I originally had a missing power rail but after repairing this nothing was happening.
Can you explain to me why this was the fix? What does this method of reset do exactly?Leave a comment:
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HP Touchsmart 310 DA0NZ2MB6F0 No Boot
Hello all,
I have this computer HP touchsmart 310 with DA0NZ2MB6F0 motherboard. The issue is that it turns on but doesn't do much else. No HP logo on screen, no backlight, no hard drive activity (it turns on), no nothing. Hard drive spins up but does not do much besides spin. No signs of life besides everything going on. I tried resetting with the power button and also tried clearing the CMOS. Anyone have any other advice as to what the issue here could be? I appreciate it, thanks. -
Re: HP 15Z shorted QFN with weird ID
thanks guys, i lost track of this project but it seems it is indeed this SY8286BRAC, online pictures show something that looks identical except for last 3 digits. Are there known more common replacements for this IC?Last edited by TVMexicana; 05-30-2019, 08:38 AM.Leave a comment:
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Lenovo Yoga 3 NM-A381 No Power
Hello all,
I'm trying to repair this motherboard which will not turn on. Initially I found a short on +5VALW the always on 5V rail and it turned out to be a shorted U8 which is a usb power supply. I replaced this part but despite the short being gone now, the rail does not turn on. I tried removing the part again and it makes no difference. When i force enable PU202 to turn on it will make +5VALW just fine but it squeals a bit. If i isolate this output the squeal goes away. It seems something draws too much current perhaps but there is no low resistance reading from this line to...Last edited by TVMexicana; 05-25-2019, 11:39 PM. -
Re: Macbook Pro A1502 Slow and No Fan with Error Codes
Sorry, completely forgot to post the motherboard no. It is an 820-00164A. Will report my findings in a bit.Leave a comment:
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Macbook Pro A1502 Slow and No Fan with Error Codes
Hello all,
In the process of diagnosing this issue. This macbook boots up and everything but is thermal throttling, has the kernel_task process taking up 300% CPU and has no fan spinning. When I run hardware diagnostic the fan does spin properly but the problem won't go away. Have tried NVRAM and SMC reset. Hardware diagnostic gives me codes PPN001 and PFM006.
I am going to be taking the board to find possible corrosion issues and I already see a ground plane that has some dark patina, there might be more on the opposite side of the board.
Any ideas... -
HP 15Z shorted QFN with weird ID
Hello all,
I am continuing to trouble shoot motherboards. This time around I have found a bad QFN chip responsible for one of the power rails in this HP 15z-cd000. It is a DC-DC converter circuit. Dead short to ground through this IC. I'd like to replace it but the number on it is probably propiertary, it is marked something like AWV70H or possibly AWV709, or AWV7DH. I can't exactly tel but googling does not give me any results. I'd really love to be able to replace it as I think it's the only issue with this MB. I'm gonna try to dig through some junkboards and see if I can find... -
HP 15z Motherboard: G94C DAG94CMB6D0 Rev D
Hello,
Am trying to repair this motherboard and need some info on a bad QFN Chip. Does anyone have a schematic for it? I'd hugely appreciate it. Thanks! z Either that or if you can help me figure out what this QFN chip is which is marked AWV70H. It's part of a DC-DC Supply Circuit.
HP 15z-cd000 G94C DAG94CMB6D0 Rev D Motherboard.Last edited by TVMexicana; 05-16-2019, 04:47 PM. -
Re: HP G7 no signs of life DAR18DMB6D0
I replaced the part but no change. Pretty sure I soldered it properly too.
I still don't have some of the vital signs we talked about. PCH is not being taken out of reset, RSMRST isn't going high. DNBSWON does not go down when I push power.
I will go through the check list again tomorrow but in the meantime do you have any other ideas of what I could check?
One thing I did discover is that the hall effect sensor looks to be shorted, when i put a magnet on it the state of the output will not change. I...Last edited by TVMexicana; 04-26-2019, 11:16 PM.Leave a comment:
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