Hello, I have a pcb from an e scooter which had a faulty diode but even after removing it from circuit, it still has a short to ground on the three components circled. I have removed every cap on the board and tested one by one and the short is still there and all the caps test ok. Could this be because I haven’t put a diode back on it yet or where do I go next please?
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check the regulator -
Before that, disconnect any cables connected to the board.
Inject the low voltage and see which component is getting hotComment
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Which one is the regulator please?Comment
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Also, when injecting voltage where would I put the positive wire in the picture please?Comment
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kia117 is a regulator, so is the 6pin chip
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How can I check it and in what mode on the multimeter pleaseComment
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Which pins on the regulator do I test to see if it’s shorted please and in what mode on the multimeter also in or out of circuit?Comment
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Thank you where is 3.3v pleaseComment
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There is a continuous beep between 12v and ground pin you pointed out in the picture.Comment
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check between the 3 pins on the 117, if any combination beep then remove it and test again.
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Do I test from ground plane to each pin of the 117?Comment
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Clearly, this regulator is giving 3.3V on the output. Check now between ground and the output, then between ground and the input on the 1117 regulator. See which one shows lower resistance. Or, try injecting a low voltage on the VIN, VOUT, or the 12V line. Any component on the board that takes high current will heat up quickly. Or you can use the multimeter in ohm mode to find the pin that gives the lowest resistance to ground. That's all.Attached FilesComment
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So I test between ground and the input leg of 117 in resistance mode right?Comment
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here it is
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So I test between the ground leg of 117 (pin 1) and input voltage leg of 117 (pin 2) or the ground plane of the pcb itself please?Comment
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The ground is shared and connected all over the board.
Pin 1 of the regulator or the board itself is the sameComment
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Thank you So I test between the ground leg of 117 (pin 1) and input voltage leg of 117 (pin 2)Comment
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hello everyone , working zebronics power suply 450 watts , 5v ,3.3v givin short to ground black wire, also in circuit at output, resistor was charred but shows right values , after removing resistors 39ohms, 51 ohms, there was no short , no continuity beeps with ground , but after replacing new resistors (now i am not switching it on) ,again short still exists . when i put bigger ohm resistor like 100k ohm , no short beeping sound comes , lower ohm resistor gives continuity beeps ,other big ones donest , as its a working psu , i am confused what to remove now or how to go further now .
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Hi everyone,
I'm having a serious issue with my ASUS Zephyrus GA401I (4 years old, worked perfectly until recently). The system is lagging heavily, even in the BIOS, and is charging extremely slowly (a few percent in hours), making it nearly unusable. I suspect a motherboard or power delivery issue.
Symptoms:- Severe lag across the system, including BIOS navigation.
- Slow boot times and unresponsive performance in Windows.
- Battery charges very slowly (e.g., ~5% in 2–3 hours).
- No error messages or BSODs, just extreme sluggishness.
What I've Tried:- Replaced
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Hi everyone,
I'm having an issue with my Lenovo ThinkPad P43s. The laptop does not power on when the internal battery is connected, but it works fine on AC power alone (battery disconnected). Once the battery is reconnected, the system becomes completely unresponsive — no lights, no fan spin, nothing.
Here's what I've tried so far:- Power/EC reset (held power button for 60 seconds with battery and AC disconnected)
- Booted successfully on AC power only with the battery disconnected
- Visual inspection of the battery — no swelling, burn marks, or connector damage
- Battery
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Hello everyone,
I'm currently diagnosing a MacBook Pro A1707 motherboard that does not power on. I've gathered some data but am stuck and need expert advice.
Note that i'm a beginner in electronics and i'm trying to learn while trying to repair this macbook that my work gave me. I'm really curious and love understanding how thing works and i already learned so much.
Only one usb c port is taking 20v and have 12.5v on PPBUS_G3H. when trying other ports, 2 are not going to 20v and one is going to 20v but the CD3215 is getting really hot.
Observations... -
Hello everyone,
Firstly sorry for my english, french guy inside.
I brought a macbook pro A1708 - 820-00840 logic board, wasn't powering on.
History is a day, nothing happened when opening the laptop.
Nothing special inside, no corrosion, no liquid damage, never opened.
First, with the logicboard alone on the desk, mesures are :
5v017 and 0.000 amp. nothing else.
Finding a short on the PP3V3_G3H_VR, but not on the PP3V3_G3H (0.540 on diode mode), PPDCIN_G3H_CHGR_R present (5,1 volts) PPVIN_G3H_P3V3G3H around 4.1 volts. PM_EN_P3V3_G3H...
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