On the side it powers up on, does it negotiate more than 5V?
Not turning on at all means an issue with the CC lines. Since it works one way but not the other I'd say the port itself being bad is very likely.
hobostove
Senior Member
Last Activity: Today, 10:41 PM
Joined: 05-08-2023
Location: Austin, TX
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Always dump a backup of the original bios. It contains DMI information (serial number, model number, etc) and your windows key. Someone can use your dump to reconstruct a new bios with the right info moved over.
When you get your programmer, post the dump here. And read this for what info is needed for the post. [URL="https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/bios-requests-only/91593-rules-update-for-bios-requests-offers-avoid-banning-read-before-posting"]https://www.badcaps.n...Leave a comment:
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Not available, yetLeave a comment:
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The switch chip may have been broken for a while, and you just noticed it because you were actively looking for a problem. Don't think it's related to the USB-C issue.
The fact that it got worse overtime and didn't just suddenly stop makes me think the port is dirty or damaged. Try to get a good look at the pins. You'll need a magnifying glass or microscope, etc.
What does the J7-C tester say on that port? Does its screen come on?Leave a comment:
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It's possible it's just a coincidence. One way to find out is you can power it up with that chip taken out. You just won't have 5V on that USB-A port, so it won't work. But everything else will work fineLeave a comment:
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Yeah, switch is definitely dead. The 5V in has only 14.5 ohms to jump to ground. No wonder is was getting so hot. Almost 2 watts going through that tiny chip!
Thermal Resistance Junction to Case, (θJC)
SOT-23-5. . .60°C/W ([B]Means it was about 120C above room temperature[/B]) 😅
Board is good. Time to order a chipYeah, switch is definitely dead. The 5V in has only 14.5 ohms to jump to ground. No wonder is was getting so hot. Almost 2 watts going through that tiny chip!
Thermal Resistance Junction to Case, (θJC)
SOT-23-5. . .60°C/W ([B]MeansLeave a comment:
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Looks like a switch/mosfet. It may have gone short. Remove it like mon said, and test resistance between each of IN, OUT, and GND pins. Should be 6 readings. Also test the board pads resistance of IN and OUT to GND. Let us know what you find.
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[ATTACH=JSON]{"alt":"Click...Leave a comment:
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Checked all the coils for shorts? Sounds like something is unhappy power-wise. Some pictures of the board especially the charger IC area would be helpful.Leave a comment:
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Have some board photos? The whole board and a shot of the chip would be helpful.
What was the original issue with the RGB before you replaced the KB? You said it got worse.Leave a comment:
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It's alive under load! I couldn't have done it without all of you, I learned a lot from this little detour. I feel a lot more confident approaching power supplies now. Big thanks to [B]прямо[/B], [B]Per Hansson[/B], [B]CapLeaker[/B], and special thanks to [B]c1q3[/B] for getting the ball rolling in the beginning. Sorry trash can, but you're going hungry today! 😉
Just a quick recap of everything it took:
TNY284 chip for 5VSB
Fusible resistor
15V Zener diode
2 transistors
CM6500UN PFC chip
all because someone dropped a screw in the...Leave a comment:
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It was my crappy tester again, loose connection. I think it's time to retire it. 12V is present after all! Next step now is to load it and see what happens 🤞Leave a comment:
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Anyone have some guidance on where to start tracking down why 12V is missing? I have 5V and 3.3VLeave a comment:
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Alright, new PFC chip arrived. Put it in, and now seeing 375 on the main cap. Tester stays on steady now, but no 12V yet. More to do!Leave a comment:
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I used AON7380. I ended up finding the first DC-in mosfets were short. Once I replaced those the low charging mosfet survived. It's charging now.Leave a comment:
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I found the low side mosfet PQ706 was shorted. I replaced it with one that tested good, but that one went short immediately. I tried another, and same thing, shorted. There's no short on the board. What could be killing these mosfets?Leave a comment:
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Okay, ordered another battery to rule that out.
The battery is at 11V right now. When I add AC power, the battery connector goes up to 19V briefly, then settles down at 11.5V, but it's not taking current. Taking off AC power, and it goes back down to 11V. I replaced the BQ chip.
I'm thinking one of the mosfets?
Datasheet: [URL]https://www.badcaps.net/forum/showthread.php?t=74069[/URL]https://Okay, ordered another batter..., then settlesLeave a comment:
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Looks like that resistor was in series with VCC going to the PFC IC. PFC IC is shorted. VCC pin is 3ohms to ground with the chip off the board. 5VSB is back with the chip off. Going to order one. I'll be back in a weekLeave a comment:
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Found an open resistor near the PFC IC, has a hole in it. Replaced it and now 5VSB is shorted again. Getting there!Leave a comment:
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What's the model of the power supply?Leave a comment:
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PFC OUT signal looks like this on the scope, pretty much nothing
[ATTACH=JSON]{"alt":"Click image for larger version Name:\timage.png Views:\t0 Size:\t303.1 KB ID:\t3615946","data-align":"none","data-attachmentid":"3615946","data-size":"full","title":"image.png"}[/ATTACH]...Leave a comment:
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