820-00239 - short PP3V3_G3H

[Palhano]

Clean board, stuck at 5v.

I checked the LDOs lines of the CD3215 and everything is normal.

I found a short on the PP3V3_G3H line, trying to find where the short was, the board started working again and the short disappeared. 10 minutes later it stopped working and the short came back.

I injected voltage, it only pulls 0.05a and nothing heats up.

 

[2informaticos]

What is the exact ohm resistance of the short?

BTW, allow 10-15s since power is removed, before checking diode mode, or ohm scale.

 

[Palhano]

Yes, I always wait to download.

In ohms, it's reading 4.9

 

[2informaticos]

I suspect a capacitor with internal fracture.

 

[Palhano]

Any suggestion?
I analyzed all the components of the line, I replaced 2 that were ugly. But I can't find the short one. Maybe some CD3215 or other IC?

 

[2informaticos]

If the ohm value is around 5 ohm, you can't inject important current.
Nothing will get really hot.
You may need a thermal camera to detect small temperature differences on the board.

Start injecting low voltage.
Higher voltage causes bit more current and internal fracture may get clean.
The short will disappear, until that fracture get shorted again.