• Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

It is currently 14 December 2024, 05:37

 [SOLVED] Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

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  1. Topic title should contain: the device's manufacturer, full model and the brief description of problem.
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#1 Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by ARSiq • 17 January 2024, 15:57
I got this board after someone droped a screw on it with battery conected. Result is in picture.
Image
I replaced PU4501, repaired missing track and now i have 3,3V. KBC was overheating, so i repleced it too.
I have 3,3V, 5V, 1.05V, but after pressing power switch all i get is orange LED near power connector, working only as long as switch is pressed. DCBATOUT is only 12V on power supply, or 16 on battery, so i changed PU4401 too. Did not help. All tranzistors around it are OK.
Any advice please.
TIA Matus.

Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by Google Adsense [BOT] • 17 January 2024, 15:57

#2 Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by matic • 18 January 2024, 16:59
Hello!

Measure the resistances to ground on all coils.

#3 Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by ARSiq • 19 January 2024, 11:01
PL4501 9,4K
PL4701 10 ohm
PL4802 6,3 ohm
PL4801 6,3 ohm
PL5001 35 ohm
PL5201 47,5 ohm
PL4401 52k
PL5101 570ohm
PL4502 56k

#4 Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by Machine • 19 January 2024, 11:40
Measurements taken after pressing the power on button.
Measure the voltages on pins 4, 18, 27, 36, 52, 122, 128 of KBC.
Measure the voltages on pin 126 of the KBC in the following cases:
to power OFF
with power on pressed
to power "ON".

#5 Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by ARSiq • 19 January 2024, 14:32
Pin 4 3,3V in all cases
Pin18 1,18V in all cases
Pin27 3,3V in all cases
Pin36 3,27 in all cases
Pin52 0,55V in all cases
Pin122 2,88 in all cases
Pin128 3,2V in all cases

#7 Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by ARSiq • 19 January 2024, 15:47
resistane 99,4k
PIN 8 PU5101 0V in all states
U4001
1 3,3V
3 0V
5 0V
8 3,3V
14 0V
in all states

#8 Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on  [SOLVED] 

by matic • 19 January 2024, 16:24
- Measure the voltages to ground on both pins of quartzs X1802, X2401 (if both are present). It's best to measure it with an oscilloscope, if you don't have it, measure with a multimeter.
- Measure the voltage to ground on pin 3 of diode D2503.
Diode D2503 pinout:
Image
- Measure the voltages to ground on pins 5, 25, 29, 30, 31, 54, 66, 69, 88, 121 of KBC chip.

- Measure the voltages to ground on pins 52, 127 of KBC chip in the following cases:
a) Power button released.
b) Power button pressed.

#9 Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by ARSiq • 22 January 2024, 15:56
Suddenly i have short on 5V rail. 2 chips gone. Im done with it, throwing it in trash.
Thank you very much for your time and help.

Re: Dell Latitude 3500 Bolt-L UMA MB 17938-1 wont power on

by Google Adsense [BOT] • 22 January 2024, 15:56
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