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820-3332-a no power up missing PPBUS_G3H
- Thread starter lukazmac
- Start date
U7000 shouldn't get hot.
"changed u7000"
Which was the reason to change it?
Resistance to ground (diode mode) at L7030?
Do you get steady 3V42 and SMC_RESET_L?
Check Q7030/35and C7025.
"changed u7000"
Which was the reason to change it?
Resistance to ground (diode mode) at L7030?
Do you get steady 3V42 and SMC_RESET_L?
Check Q7030/35and C7025.
"ressistance to ground on L7030 - 1.6 OHM"
So you powered up a shorted board...
Remove F7040/41 and see where the short remains.
Do NOT power the board again, until short is gone.
So you powered up a shorted board...
Remove F7040/41 and see where the short remains.
Do NOT power the board again, until short is gone.
So the short is on the system side.
Now check which big coil gest the same value (1.6 ohm) to ground.
Start with L7510/20/30 and L7550/60.
Now check which big coil gest the same value (1.6 ohm) to ground.
Start with L7510/20/30 and L7550/60.
Check which one gives lower ohm value to PPBUS_G3H.
That one will disclose the burnt high-side MOSFET.
In fact these coils are in group of 2-3.
If you get 3-3.5 ohms is OK.
Less than 0.5 ohm will point you to the culprit.
After that, measure G-S ohm value for the respective MOSFETs of the group.
Usually one from 2, or 3 connected in the same rail is shorted.
That one will disclose the burnt high-side MOSFET.
In fact these coils are in group of 2-3.
If you get 3-3.5 ohms is OK.
Less than 0.5 ohm will point you to the culprit.
After that, measure G-S ohm value for the respective MOSFETs of the group.
Usually one from 2, or 3 connected in the same rail is shorted.