Re: lenovo Yoga 910-13IKB black screen
This is why you're the grandmaster in these parts......
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Re: Crazy behaviour Acer 573G
You're reporting conflicting things. Initially you said that after boot everything works fine. Now you are saying that some devices also do not appear in Windows.
If the latter is the case, you are looking at power problems or some fault related to PCI.
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Re: Dell 1564 does not charge battery
ACAV_IN on this board is produced from charger's ACOK, which is a key signal indicating that the external power is functioning. If this signal comes out of the charger intact (3.3 v) but shows up as some other voltage in the ALW power switching circuit, then it is clearly a problem that needs to be fixed.
PQ1 is a P-channel mosfet. It is open only if the voltage on the gate is lower than the voltage on the input. If you're seeing same voltage on all three pins, the chances are the mosfet is blown. Measure gate to drain and source...
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Re: lenovo Yoga 910-13IKB black screen
It's possible, yes. You can test the RAM by measuring the 3.3, 1.5/1.35 and the reference voltage that's half of the 1.5/1.35 one. Don't forget to look at the power ok and enable signals.
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Re: lenovo Yoga 910-13IKB black screen
I see what you mean. Is this a netpad or some other miniature laptop? Having 8v for VIN would be a very.. unorthodox approach. I still dont think this would normally be the case, but I guess everything is possible.
If 8V is the correct voltage, and the machine stops initializing before the graphic core is powered up, that's the part of the initialization sequence you will have to look at. I'd begin with standard RTC battery, oscillators, and coil resistance checks.
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Re: Acer 5349 charging problem
Stop guessing, debug the circuit....
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Re: Crazy behaviour Acer 573G
Unless for some reason there's an incorrect BIOS version installed, I would exclude it, yes. The chances of a flash chip being corrupt enough to ignore a significant chunks of periphery but nothing else are doubtful. I'm less certain about the ITE but this would be easily testable by checking the enable signals on the secondary power supplies.
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Re: lenovo Yoga 910-13IKB black screen
What do you mean first big coil? The 20V rail has no coils on it. After the initial switching mechanism, it is distributed to secondary power supplies, none of whom should be accepting or producing 8V. So whatever coil you're measuring at isn't 20V and, more importantly, there is not and can not be anything like 8V anywhere on the board. You are looking at a fault. Please identify the coil.
You need to test every rail, not just the cpu and graphics ones.
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Re: Lbss139lt1g
It absolutely can be fixed. It'll require skillz, a dremel, a microscope and UV mask & light but it can be fixed.
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Re: lenovo Yoga 910-13IKB black screen
Please identify the board correctly and post schematics.
I dont think there should be anything like 8V anywhere on the board.
GPU power up is nearly the last stage of the power sequence and you should be speculating about the stage before that failing.
To measure low resistance rails, use ohm mode and not diode mode.
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Re: lenovo v510-15ikb rev: f DA0LV6MB6F0
Entirely possible one of the rails can't sustain its normative load. You will have to test.
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Re: Acer 5349 charging problem
It's a typical problem, actually. Something wrong with the charger circuit.
Please identify the board correctly.
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Re: Crazy behaviour Acer 573G
Here's your schematic [url]https://drive.google.com/file/d/1GtIJA4OlvxEpO8SCrtuTzpTbdVAg6pDv/view[/url]
You can start exploring the specifics.Re: Crazy behaviour Acer 573G<br /> ...the specifics.Re: Crazy behaviour Acer 573G
Here's your schematic [url]https://drive.google.com/file/d/1GtIJA4OlvxEpO8SCrtuTzpTbdVAg6pDv/view[/url]
You can start exploring the spe
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Re: Crazy behaviour Acer 573G
Please identify the board correctly.
4.8 is a little low. Do you have a lab PSU? You should look for a pattern in power draw. What do you mean spin up regularly? Do they come up and down in a cycle?
Because all the periphery you're describing feeds off 3.3/5 power rails, you should probably start looking there first. Look for things that overheat, low resistances, suspiciously looking elements and solder.
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Re: lenovo v510-15ikb rev: f DA0LV6MB6F0
Probably related to overheating or protection triggering due to [false] power draw. You need to check the cooling system, the temperature sensors and all power rails.
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Re: Troubleshoot working laptop HP 840 G1 ?
I dont know the correct voltage off the top of my head. The schematic for this or similar HP laptop will contain the exact values. You can think of the middle pin as connected to the positive wire with a resistor but in practice this is not the case. As I said, there is a circuit in the charger that can lower this voltage in real time, as a protection method. This also means that if you are powering the machine with a lab PSU, which is a very useful thing to do because it lets you monitor the current draw, you need to lie to the board...
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Re: Asus 1001PXD REV. 1.1 blinking led light
Very simple, identify the IC next to it. If this is feeding a big chip like the CPU it may very well be the normal resistance for that rail....
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Re: lenovo E520 no start main LGG-1 MB10292-2
Sorry I will have to look at this again later on, at work right now
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