Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Laptops, Tablets, and Mobile Devices
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 10-19-2021, 12:45 AM   #21
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

Quote:
Originally Posted by Andreasbest View Post
Hello again.
PL5 one side is indeed grounded but i think is normal, all rest coils are fine, no shortcircuits to ground.
Indeed both sides are grounded, wrong measure before (probably probe needed some more pressure on lead)
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 05:02 AM   #22
Sephir0th
Badcaps Veteran
 
Sephir0th's Avatar
 
Join Date: Oct 2020
City & State: Wangerland
My Country: Deutschland
Line Voltage: 230VAC 50Hz
I'm a: Hobbyist Tech
Posts: 318
Default Re: Dell E5440 completely dead

Ok. So it seems most of the parts on the supicious rail were checkd, except PQ5 and PU701, right?
Sephir0th is offline   Reply With Quote
Old 10-19-2021, 05:43 AM   #23
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

Quote:
Originally Posted by Sephir0th View Post
Ok. So it seems most of the parts on the supicious rail were checkd, except PQ5 and PU701, right?
Seems so, what do you suggest?
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 06:09 AM   #24
Sephir0th
Badcaps Veteran
 
Sephir0th's Avatar
 
Join Date: Oct 2020
City & State: Wangerland
My Country: Deutschland
Line Voltage: 230VAC 50Hz
I'm a: Hobbyist Tech
Posts: 318
Default Re: Dell E5440 completely dead

Unfortunately i can't find datasheet right no for PU701, but you can at least check whether 19V reach Pin1 and of course, you can check each pin for short to GND
Sephir0th is offline   Reply With Quote
Old 10-19-2021, 06:39 AM   #25
Spider1211
Badcaps Veteran
 
Join Date: Oct 2019
City & State: Morcellement
My Country: Mauritius
Line Voltage: 230VAC, 50Hz
I'm a: Knowledge Seeker
Posts: 501
Default Re: Dell E5440 completely dead

How many amps is the board taking?
Spider1211 is offline   Reply With Quote
Old 10-19-2021, 06:40 AM   #26
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

5 6 7 14 15 & 32 are grounded
Pin #1 receives 19.5v
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 06:41 AM   #27
Spider1211
Badcaps Veteran
 
Join Date: Oct 2019
City & State: Morcellement
My Country: Mauritius
Line Voltage: 230VAC, 50Hz
I'm a: Knowledge Seeker
Posts: 501
Default Re: Dell E5440 completely dead

How many amperes? Do you have a bench power supply? If yes, set it to 19.5V and power the board from it.
Spider1211 is offline   Reply With Quote
Old 10-19-2021, 06:41 AM   #28
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

Quote:
Originally Posted by Spider1211 View Post
How many amps is the board taking?
You mean if i apply 19v directly to DC_IN?
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 06:44 AM   #29
Spider1211
Badcaps Veteran
 
Join Date: Oct 2019
City & State: Morcellement
My Country: Mauritius
Line Voltage: 230VAC, 50Hz
I'm a: Knowledge Seeker
Posts: 501
Default Re: Dell E5440 completely dead

Check where the DC adaptor connects to the motherboard. Apply power from your power supply on the DC connector pins, just make sure which is +ve and -ve first.
Spider1211 is offline   Reply With Quote
Old 10-19-2021, 07:20 AM   #30
Sephir0th
Badcaps Veteran
 
Sephir0th's Avatar
 
Join Date: Oct 2020
City & State: Wangerland
My Country: Deutschland
Line Voltage: 230VAC 50Hz
I'm a: Hobbyist Tech
Posts: 318
Default Re: Dell E5440 completely dead

PU701 Pin 6 & 15 short to GND means Main Power Rail short to GND. How could that Be missed before?

Last edited by Sephir0th; 10-19-2021 at 07:23 AM..
Sephir0th is offline   Reply With Quote
Old 10-19-2021, 08:05 AM   #31
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

Quote:
Originally Posted by Sephir0th View Post
PU701 Pin 6 & 15 short to GND means Main Power Rail short to GND. How could that Be missed before?
Yes i can confirm pin 6 and 15 of PU701 are both grounded.
What do you suggest?
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 08:10 AM   #32
Spider1211
Badcaps Veteran
 
Join Date: Oct 2019
City & State: Morcellement
My Country: Mauritius
Line Voltage: 230VAC, 50Hz
I'm a: Knowledge Seeker
Posts: 501
Default Re: Dell E5440 completely dead

Do a visual check first to identify if something is physically damaged, otherwise Inject voltage on that line and see what gets hot. As always, start with 1V 1A then increase amp slowly if needed.
Spider1211 is offline   Reply With Quote
Old 10-19-2021, 08:11 AM   #33
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

Did visual inspection before, totally clean mb.
Gonna inject voltage and report in 2 mins
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 08:15 AM   #34
Sephir0th
Badcaps Veteran
 
Sephir0th's Avatar
 
Join Date: Oct 2020
City & State: Wangerland
My Country: Deutschland
Line Voltage: 230VAC 50Hz
I'm a: Hobbyist Tech
Posts: 318
Default Re: Dell E5440 completely dead

First, Share exact Résistance to GND there in Ohms Mode, Range 200 or Auto-Range to exclude a Short with a step down Circuit.
Sephir0th is offline   Reply With Quote
Old 10-19-2021, 08:19 AM   #35
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

When i set it to Ω shows 20Ω not 0.
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 08:20 AM   #36
Sephir0th
Badcaps Veteran
 
Sephir0th's Avatar
 
Join Date: Oct 2020
City & State: Wangerland
My Country: Deutschland
Line Voltage: 230VAC 50Hz
I'm a: Hobbyist Tech
Posts: 318
Default Re: Dell E5440 completely dead

20 Ohms are probably Bad News. Now you have to Check Resistance to GND of each coil. Look for a similar value...
Sephir0th is offline   Reply With Quote
Old 10-19-2021, 08:40 AM   #37
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

I see same value only on PL400 (both pins) all other coils have values way beyond this.
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 08:49 AM   #38
Sephir0th
Badcaps Veteran
 
Sephir0th's Avatar
 
Join Date: Oct 2020
City & State: Wangerland
My Country: Deutschland
Line Voltage: 230VAC 50Hz
I'm a: Hobbyist Tech
Posts: 318
Default Re: Dell E5440 completely dead

That's fine then. So Voltage injection Like mentioned before. Pay Attention especially To PU401 and PU701.
Sephir0th is offline   Reply With Quote
Old 10-19-2021, 08:51 AM   #39
Andreasbest
Badcaps Veteran
 
Join Date: Aug 2014
City & State: Around the country...
My Country: Hellas ( Greece )
I'm a: Knowledge Seeker
Posts: 731
Default Re: Dell E5440 completely dead

I inject voltage on pin 6 (+) and GND (-), 1v 1a and drown only 0.4A, no shortcircuit indication.
Andreasbest is offline   Reply With Quote
Old 10-19-2021, 08:52 AM   #40
Spider1211
Badcaps Veteran
 
Join Date: Oct 2019
City & State: Morcellement
My Country: Mauritius
Line Voltage: 230VAC, 50Hz
I'm a: Knowledge Seeker
Posts: 501
Default Re: Dell E5440 completely dead

They both share a common line through PR400. You could try removing PR400 to see which side is 20Ohms.

I suspect it might be a faulty PU701. These are fairly easy to remove and resolder. I'd try removing it and see if the 20Ohms is still there. Or you could just inject voltage, but with 20Ohms at 1V, I doubt anything will get hot (expected 0.05A flow).
Spider1211 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums © 2003 - 2022
Powered by vBulletin ®
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 08:35 PM.
Did you find this forum helpful?