Diagnosing short to ground issue. pcb from an e scooter

[Leefreeman97]

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?

[petehall347]

check the regulator

[khalillll]

Before that, disconnect any cables connected to the board.
Inject the low voltage and see which component is getting hot

[Leefreeman97]

Which one is the regulator please?

[Leefreeman97]

Also, when injecting voltage where would I put the positive wire in the picture please?

[stj]

kia117 is a regulator, so is the 6pin chip

[Leefreeman97]

How can I check it and in what mode on the multimeter please

[petehall347]

How can I check it and in what mode on the multimeter please

see if its shorted

[Leefreeman97]

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?

[khalillll]

Before that, disconnect any cables connected to the board.
Inject the low voltage and see which component is getting hot

On beep mode, check if there’s a short on 3.3 V or 12 V (continuous beep). Then try voltage injection: lower the voltage and inject on the positive rails. On the regulator Vout, don’t exceed 3 V, and see which component is getting hot

[Leefreeman97]

Thank you where is 3.3v please

[Leefreeman97]

There is a continuous beep between 12v and ground pin you pointed out in the picture.

[stj]

check between the 3 pins on the 117, if any combination beep then remove it and test again.

[Leefreeman97]

Do I test from ground plane to each pin of the 117?

[khalillll]

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.

[Leefreeman97]

So I test between ground and the input leg of 117 in resistance mode right?

[petehall347]

here it is

[Leefreeman97]

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?

[khalillll]

The ground is shared and connected all over the board.
Pin 1 of the regulator or the board itself is the same

[Leefreeman97]

Thank you So I test between the ground leg of 117 (pin 1) and input voltage leg of 117 (pin 2)