Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

[sikocan]

Dell Vostro 5490
Service Tag: G8T7NW2
Motherboard Model: Mantis CML 18778-1

Schematics: Attached in the Google Drive folder.
BRD File: Attached in the Google Drive folder.
Video of the issue: https://youtu.be/bIXaiiub664 (Also on Google Drive)

Google Drive link: https://drive.google.com/drive/folde...j_?usp=sharing

I've attached Resistance Readings at 200ohms range. Voltage Readings, with and without power button being pressed. Detailed board pictures. Old and new BIOS files attached.


Problem: No DC Jack LED when plugged in and the unit will not power on. When power button is pressed, the DC Jack LED becomes Orange, but only as long as you hold it. If you let go of the power button, Orange LED will stop. No reaction on fan. Battery does not charge. Stays at current battery voltage at 8.85V even after leaving it connected for longer time. When DC Jack is plugged in, battery voltage is 12.56V.

The following are the attempts so far:
1. Disconnected every other component such as WiFi chip, Keyboard, Keyboard Backlight, TrackPad, Daugther board, Speaker, LCD and CMOS battery. Same result, except for Fan. Same result.
2. 2 other Genuine Dell chargers + Type-C to Dell Charger tip as shown in video. Same result.
3. There are 2 Chips, 8MB and 16MB, I have flashed both from https://shorturl.at/cr015 VinaFix (Files are in the Google Drive. Old backed up BIOS files are also on the Google Drive).
4. I noticed PU4403 & PU4405 N-Channel Mosfets are AON7380, Gate to Source would be shorted to 0 ohms when charger is in.. When I remove the MOSFET, outside the board, it closes and opens fine and no short between G & S. I have replaced it with MOSFET AON7466 which main difference is the Rds ON Vgs at 10V is 0.7 ohms difference which shouldn't make much difference. Same issue with this MOSFET. So when the MOSFET is installed, no power applied, G & S are normal, not shorted, high resistance, as soon as Power is applied, it'll go to 0.
5. I've replaced with new ISL9538HRTZ on PU4401.

Measurements of importance:
CMOS battery 2.99V

Battery Cells look good, not swollen/pregnant. Tried 2 more batteries, same issue.

[mon2]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Gate to Source would be shorted to 0 ohms when charger is in..

Be sure to measure RESISTANCE or DIODE mode readings with no power to the logic board.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Good to know, but these measurements are when power is not in the board. Residence and diode mode, no power.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Voltage readings for ISL9538HRTZ

1. 12.58
2. 12.58
3. 12.58
4. 13.12
5. 11.07
6. 7.96
7. 1.91
8. 5.16
9. 1.98
10. 1.95
11. 8.04
12. 13.07
13. 9.8
14. 20.35
15. 20.35
16. 20.25
17. 20.17
18. 5.16
19. 3.98
20. 0
21. 3.36
22. 3.36
23. 3.34
24. 3.36
25. 2.82
26. 0
27. 0
28. 1.42
29. 0
30. 0
31. 12.43
32. 12.58

[mon2]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Measure the voltages on PU4415. This is a P-channel mosfet so gate must be lower than the voltage being passed between source / drain. Need to check if it is leaking.

The mosfets @ PU4403-PU4406 are N-channel mosfets. They require the gate voltage to be higher than the source / drain voltage but the present measurements do not show a boosted voltage.

Is a battery connected ? Connect it and check if the 19V_DCBATOUT is at a proper value.

[BalkanBoy]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Since you said you got LED only while power button is pressed I would say it's got something to do with EC, either faulty firmware or chip itself, but I'm just guessing.

[mcplslg123]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Need to know the voltage on pin1-4-8 of dc in fets as that will only confirm whether b+ rail is powered or not. No dc jack light may be 'coz of absence of 3V LDO.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Hi all,

Values for PU4415
PIN 123, 19.682V (SOURCE)
PIN 4, 1.80V (GATE)
PIN 5678, 19.68V (DRAIN)

Values for PU4301
PIN 123, 19.682V (SOURCE)
PIN 4, 3.20V (GATE)
PIN 5678, 19.68V (DRAIN)

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

19V_DCBATOUT without Charger, but only battery in, 0.10V. With charger in, 19.68V. Thanks

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Since EC looks good condition physically, it maybe ok. However there is 2 BIOS like chips so I'm assuming, I could be wrong, it does get firmware from the smaller chip. I still suspect something wrong with main power rail or something else short down the track of power lines in S0 states causing main power rail to be shutdown.

[Sephir0th]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

It would be new for me to assume something from nothing more than the "good" physical condition. From your readings the The DC-IN area seems to be perfectly fine with chrger only. Upcoming power rails confirms that, so i wouldn't waste more time with the charging controller and the mosfets here. it's just some weird design. Please repeat the voltage measurements of ISL9538HRTZ with battery only.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

As mentioned earlier, 19V_DCBATOUT without Charger, but only battery in, 0.10V. so I'm not sure what 0.10v from battery will tell you, but I'll check tomorrow for you anyway.

[Sephir0th]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

That's already clarified and i'm ofc not interested in the voltage of the Main power rail for this reason but in what the charging controller does and doesn't with only battery present.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Hi mate,

Attached are the Voltage of pins without Charger, only Battery.
Pin 1 0
Pin 2 0
Pin 3 0
Pin 4 0
Pin 5 0.17
Pin 6 0
Pin 7 0.417
Pin 8 0
Pin 9 0.17
Pin 10 0
Pin 11 0.08 and increasing, like charging a capacitor
Pin 12 0
Pin 13 0.03
Pin 14 0
Pin 15 0
Pin 16 0
Pin 17 0
Pin 18 0
Pin 19 0
Pin 20 0
Pin 21 0
Pin 22 0
Pin 23 0
Pin 24 0
Pin 25 0
Pin 26 0.2
Pin 27 0
Pin 28 0
Pin 29 0
Pin 30 0
Pin 31 0.417
Pin 32 0

[mon2]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

That is a lot of zeros. The charger IC is not being powered in battery only mode.

Measure the voltage to ground of usb_adt. Use 30v or higher dc volts scale of your meter.

You can check at u7418 and again at PD4401.

Post the measurement.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

Voltage to ground of usb_adt is 0.0187. DC jack and Battery Connected
0.0028 with Battery only.
Resistance just in case without any power 90k ohms.

[mcplslg123]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

With only charger plugged in, 3V LDO is present?? It seems like a dead battery. Have you tried with new Battery? Your dc-in section is working perfectly.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

I've ordered a new battery just in case, waiting delivery. In the time being, 3V LDO is present, 3.37V at PU4501 Pins 16 & 17 with charger connected.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

By the way, I did try 2 different batteries with different health conditions - same result. Regardless, new battery will be Excellent health, let's see. But it should still turn on from DC Jack source. Intriguing.

[sikocan]

Re: Dell Vostro 5490 Not turning on. Orange LED when power button pressed only

New Battery
Voltage at the battery when it's not connected to board. 0V which is normal for protecion reasons.

When ONLY Battery connected to motherboard:
Voltage at BT+ (Battery connector on board) 11.17
Voltage at PR4407 11.17
Voltage at SDC_IN 0.09

ONLY Battery connected. No Charger.
1. 11.17
2. 11.17
3. 11.17
4. 4.86
5.
6. 0
7.
8. 5.16
9. 0
10. 0
11. 0
12. 4.85
13. 0.099
14. 0.079
15. 0.079
16. 0.079
17. 11.10
18. 5.16
19. 0
20. 0
21. 0
22. 0
23. 0
24. 0
25. 0
26. 0
27. 0
28. 0
29. 0
30. 0
31. 11.19
32. 3.13