HP ProBook 4510s Short Circuit

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • branch592
    Member
    • Apr 2011
    • 19
    • USA

    #1

    HP ProBook 4510s Short Circuit

    Got an HP ProBook 4510s as a stripped down shell from my local Goodwill Store. Was able to easily get it working. Unfortunately, there was a loose screw in the machine. While using it, I closed the lid to put it to sleep then turned it over to read the model number off the bottom of the machine. When turned right side up, the machine would not come to life. Seems the screw shorted something out. Found it stuck against the metal frame on the bottom of the board that holds the heatsink on. My iGo power adapter shuts down every time I plug it in to the motherboard. Hard to check the board with no power. Don't have the battery for this machine at present.

    Started by checking all the MOSFETs (see below) seen in the schematics. HP ProBook 4510s (pn FN068UT) Laptop Motherboard Schematic diagram.pdf (Attachment from another forum post). Its similar to my machine but uses DDR2 memory instead of DDR3 on my board. Looked for readings less than 30 ohms. Found several. Q5, Q12, Q16, and Q1017 are all low side transistors for the power controllers. Q1054 is my choice for the culprit (page 7 of the schematics). The ohms readings for it are way off compared to the others of its type on the board (Q3, Q6, Q11, Q1016). (link to datasheet)

    So the questions are:

    1. Is this the likely cause of the short circuit?
    2. Are there any more parts I should check?
    3. This is a very small surface mount part. 3.3 mm or 1/8 inch square leadless package. Can this be safely removed with ChipQuik or do I need to seek out the services of someone equiped with "proper" desoldering tools? All I have is a soldering iron and a Black and Decker heat gun (I think its 850 degrees on low and 1100 degrees on high).

    Thanks.



    MOSFET Readings:

    Q2 FDS6690AS
    Source to Gate = 106.2K
    Source to Drain = 3033
    Gate to Drain = 106K

    Q3 SI7326DN <<< Same As Q1054
    Source to Gate = 104K
    Source to Drain = 1718
    Gate to Drain = 97.3K

    Q5 FDS6690AS
    Source to Gate = 106.2K
    Source to Drain = 30.1 <<<<<<<<<<<<<------------- ????????????
    Gate to Drain = 106.3K

    Q6 SI7326DN <<< Same As Q1054
    Source to Gate = 105K
    Source to Drain = 1137
    Gate to Drain = 104.1K

    Q10 SI7686DP
    Source to Gate = 100.9K
    Source to Drain = 1129
    Gate to Drain = 97.9K

    Q11 SI7326DN <<< Same As Q1054
    Source to Gate = 90.1K
    Source to Drain = 1281
    Gate to Drain = 95.2K

    Q12 FDMS8660S
    Source to Gate = 98.9K
    Source to Drain = 21.3 <<< Same As Q16 -- Probably OK
    Gate to Drain = 92.9K

    Q14 FDC655BN --- Marked as 5581 --- 6-pin
    Source to Gate = 4.35M
    Source to Drain = 24.41K
    Gate to Drain = 4.33M

    Q15 SI7726DN --- Marked as 7702
    Source to Gate = 91.1K
    Source to Drain = 15.5K
    Gate to Drain = 97.1K

    Q16 FDMS8660S
    Source to Gate = 99.5K
    Source to Drain = 21.4 <<< Same As Q12 -- Probably OK
    Gate to Drain = 92.2K

    Q19 SI7686DP
    Source to Gate = 101.5K
    Source to Drain = 1134
    Gate to Drain = 98.5K

    Q21 FDC655BN --- Marked as 5581 --- 6-pin
    Source to Gate = 3.47M
    Source to Drain = 2047
    Gate to Drain = 3.44M

    Q22 SI7726DN --- Marked as 7702
    Source to Gate = 91K
    Source to Drain = 1120
    Gate to Drain = 91.5K

    Q1016 SI7326DN <<< Same As Q1054
    Source to Gate = 101.2K
    Source to Drain = 1153
    Gate to Drain = 7.17K

    Q1017 FDS6676AS
    Source to Gate = 106.4K
    Source to Drain = 51.1 <<<<<<<<<<<<<<--------------- ?????????
    Gate to Drain = 109K

    Q1029 TPC8121
    Source to Gate = 15.87K
    Source to Drain = 124K
    Gate to Drain = 137.3K

    Q1030 FDMC8884
    Source to Gate = .524M
    Source to Drain = 32.45K
    Gate to Drain = .519M

    Q1031 FDMC4435BZ
    Source to Gate = 46.7K
    Source to Drain = 7.08K
    Gate to Drain = 57.9K

    Q1032 FDMC4435BZ
    Source to Gate = 218.8K
    Source to Drain = 24.51K
    Gate to Drain = 246.0K

    Q1054 SI7326DN
    Source to Gate = 16.9
    Source to Drain = 4.5 <<<<<<<<<<<<<------------- Culprit !!!
    Gate to Drain = 20.2

    Q1063 FDMC8884
    Source to Gate = 96.6K
    Source to Drain = 123.1K
    Gate to Drain = 211K
    Attached Files
    Last edited by branch592; 03-14-2012, 09:44 PM. Reason: Adding info to post
  • b700029
    Banned
    • Sep 2010
    • 640

    #2
    Re: HP ProBook 4510s Short Circuit

    1. It depends what got shorted.

    2. Check the MOSFETs first. With them removed you can also check if any of the main power rails still have a short on them.

    3. Very small indeed. You will need hot air but 850/1100 sounds way too hot. A proper hot air rework station is recommended.

    You cannot check parts accurately in-circuit, especially ones with high-impedance inputs like MOSFETs. Even the multimeter charging up the gate can cause them to conduct.

    I would remove Q1054, Q22, Q11, and Q15 and see if that clears the short. If it does, then check each one separately out-of-circuit. With them still removed, plug in the adapter and ensure you get 3.3Vsb and 5Vsb (pins 8 and 17 of U10). Then unplug and ensure there are no shorts on the main 5V and 3.3V rails.

    Comment

    • branch592
      Member
      • Apr 2011
      • 19
      • USA

      #3
      Re: HP ProBook 4510s Short Circuit

      Going to get a local guy to replace several suspect transistors (Q1054, Q1055, Q1056) on this motherboard. He's been repairing laptops for over a decade. Don't have the money to buy a good rework station since I didn't win the MegaMillions jackpot.

      Hopefully that will get things running.

      One final question. The schematics show Q1055 as a PMV65XP. But the markings on the PMV65XP on the board, there are several, don't match. Those markings look like WM9, but the closest I found was a NXP Semiconductors PMV65XP marked as %M9. Are these the same? The dimensions of my chip is approximately 3mm by 1mm. Have attached a photo of another chip the schematic refers to as an PMV65XP with the same markings. Thanks for the help.
      Attached Files

      Comment

      • jetadm123
        Badcaps Legend
        • Feb 2010
        • 2169

        #4
        Re: HP ProBook 4510s Short Circuit

        Since they are probably using an internal factory code, it's a good thing you have the schematic. I suspect the difference between the "W" and the "%" would identify which country or factory the chip was made at. Several companies use such product codes on their smd components and without a schematic, it can be very difficult to identify the component.

        Comment

        • megatech
          New Member
          • Jun 2013
          • 4
          • nigeria

          #5
          Re: HP ProBook 4510s Short Circuit

          It's helpfull

          Comment

          • neelix baby
            New Member
            • Nov 2013
            • 5
            • Macedonia

            #6
            Re: HP ProBook 4510s Short Circuit

            HP ProBook 4520s XT943UT schematic anyone?

            Comment

            Related Topics

            Collapse

            • tofik
              MOSFET equivalent K8A60DA
              by tofik
              Hello guys,

              I have a shorted MOSFET K8A60DA with the following characteristics:
              Type Designator: TK8A60DA
              Marking Code: K8A60DA
              Type of Transistor: MOSFET
              Type of Control Channel: N -Channel
              Maximum Power Dissipation (Pd): 45 W
              Maximum Drain-Source Voltage |Vds|: 600 V
              Maximum Gate-Source Voltage |Vgs|: 30 V
              Maximum Gate-Threshold Voltage |Vgs(th)|: 4 V
              Maximum Drain Current |Id|: 7.5 A
              Maximum Junction Temperature (Tj): 150 °C
              Total Gate Charge (Qg): 20 nC
              Rise Time (tr): 25 nS
              Drain-Source
              ...
              07-19-2023, 05:18 AM
            • Jane
              How do you test MOSFET in laptops ?
              by Jane
              I tried to use this method:

              Testing an N-channel MOSFET:

              Step 1: Discharge the Gate (turn off the MOSFET)
              Place the black probe (COM) on the Source (S) and the red probe on the Drain (D). The multimeter should show no continuity (high resistance or "OL" – open line).
              Then, touch the black probe to the Source (S) and the red probe to the Gate (G). This discharges any stored charge in the Gate, turning the MOSFET off.

              Step 2: Charge the Gate (turn on the MOSFET)
              Now, place the red probe on the Gate (G) and the black probe on the
              ...
              09-27-2024, 03:31 AM
            • gpx
              HP 250 G5 (LA-D704P with a Core i7-6500U) won't POST
              by gpx
              Hi everyone, I am hoping for a little help with an HP 250 G5 with motherboard LA-D704P with a Core i7-6500U. I am new to board repair but keen to learn.

              I am sorry this post is quite long but I was trying to systematically work my way through things.

              I don't know the history of the board – I bought it as part of a job lot.

              I have attached a number of photos of both sides of the board. I cannot seem to find a schematic or boardview online.

              When plugged in to DC power the power LED lights and the battery seems to charge. It will not...
              06-18-2021, 10:39 AM
            • tantr13
              Lenovo Ideapad 5 14ITL05 not powering on
              by tantr13
              Hi everyone,
              This is my first post so I'm hoping to get some help on this awesome forum. As a preface, I'm an amateur at electronics, especially troubleshooting complicated devices like laptops. However, I'm trying to develop a skill for it so I can learn how these devices work and how to repair them without continuing the wasteful tradition of throwing them away and buying new. 🤮

              I've had a Lenovo Ideapad 5 14ITL05 for a few years now, with motherboard LA-K321P. I would never leave it plugged in unless I was using it, and always turned it off after I was done, but last week...
              06-28-2024, 06:28 PM
            • Cuboy
              HP probook 4510s mosfet issue
              by Cuboy
              Hello,

              I am currently trying to help a ONG by volunteering to help repair laptops, it's something that i have been into since 2017, always watching videos, on discords, forums etc...

              I have an HP ProBook 4510s laptop that does not power on and has no indicator lights, which suggests an issue with the power supply or the motherboard.

              I started by verifying that there is voltage at the input of the motherboard, confirming that the power adapter is working correctly. However, when I checked the voltage at the output of the first MOSFET (Q1032), I found 19V at...
              03-16-2024, 10:29 AM
            • Loading...
            • No more items.
            Working...