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Old 05-25-2012, 04:56 PM
Encrypted Existence Encrypted Existence is offline
 
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Default Stuck...power issues...bad board?..thoughts?

Hello all. I have an HP Probook 4510s on the bench.
Specs: 4 GB DDR 3 RAM
Intel core 2 duo
250 GB Hitachi HDD

I ran an extended self-test with gsmartcontrol on the HDD it passed. I have been unable to test any other components as you will see below.

Customer informed me that the machine wouldn't properly power on. The first thing that I did was test the AC adapter with my meter and the output was what it should be. I noticed that the power LED was not lit when the AC adapter was plugged in. The next thing I tried was turning the machine on myself with the battery connected (no AC adapter). The blue ring around the power button turned blue for a few seconds then went dark. I didn't see anything on the screen at all when the blue light was lit. Next, I took the battery out and tried to power on with the AC adapter plugged in. I pressed the power button and got absolutely nothing. No blue light like when the battery was connected. My troubleshooting thus far led me to believe that the machine may have a faulty DC jack so I tore the laptop down and pulled out the jack and tested it with my meter with the AC adapter plugged in. The output was what it should be (19.2v). At this point I am stumped. My instinct tells me I may have a bad mobo on my hands but I am still a beginner and I don't trust my instincts all that much just yet so I figured that I'd reach out to my fellow techs. I plan on swapping the RAM for known good but I don't think that is the issue considering I didn't get any beeps or video output that would indicate that it was a RAM issue. One of the board's caps looks ever so slightly more bulgy than the other three but I'm not sure. Thanks in advance for any help/replies.
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Old 05-25-2012, 05:02 PM
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Quote:
Originally Posted by Trusted IT Solutions View Post
Hello all. I have an HP Probook 4510s on the bench.
Specs: 4 GB DDR 3 RAM
Intel core 2 duo
250 GB Hitachi HDD

I ran an extended self-test with gsmartcontrol on the HDD it passed. I have been unable to test any other components as you will see below.

Customer informed me that the machine wouldn't properly power on. The first thing that I did was test the AC adapter with my meter and the output was what it should be. I noticed that the power LED was not lit when the AC adapter was plugged in. The next thing I tried was turning the machine on myself with the battery connected (no AC adapter). The blue ring around the power button turned blue for a few seconds then went dark. I didn't see anything on the screen at all when the blue light was lit. Next, I took the battery out and tried to power on with the AC adapter plugged in. I pressed the power button and got absolutely nothing. No blue light like when the battery was connected. My troubleshooting thus far led me to believe that the machine may have a faulty DC jack so I tore the laptop down and pulled out the jack and tested it with my meter with the AC adapter plugged in. The output was what it should be (19.2v). At this point I am stumped. My instinct tells me I may have a bad mobo on my hands but I am still a beginner and I don't trust my instincts all that much just yet so I figured that I'd reach out to my fellow techs. I plan on swapping the RAM for known good but I don't think that is the issue considering I didn't get any beeps or video output that would indicate that it was a RAM issue. One of the board's caps looks ever so slightly more bulgy than the other three but I'm not sure. Thanks in advance for any help/replies.
If I'm reading it right the power supply is clamping down in a fault condition under load. When you pulled the power jack it looks like you were testing with no load is that correct? I would pull out everything you can and see if the power supply lamp will stay on.
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Old 05-25-2012, 05:24 PM
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If I'm reading it right the power supply is clamping down in a fault condition under load. When you pulled the power jack it looks like you were testing with no load is that correct? I would pull out everything you can and see if the power supply lamp will stay on.
Yes, you are correct. I just tested the jack while it was connected to mobo with nothing but CPU installed. Still no light. I also went ahead and tested the pins (or leads?) coming from the dc jack connector going into the mobo. I am getting 19.2v. Should I take out the CPU as well and then test again?

Last edited by Encrypted Existence; 05-25-2012 at 05:34 PM.
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Old 05-25-2012, 05:37 PM
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Yes, you are correct. I just tested the jack while it was connected to mobo with nothing but CPU installed. Still no light. I also went ahead and tested the pins coming from the dc jack connector going into the mobo. I am getting 19.2v. Should I take out the CPU as well and then test again?
So the light is on with no load and goes dim or off connected? If it goes off you should measure low or no voltage across the pins you were measuring before. Check the usbs i can't remember the exact symptoms but i had one a while ago where the plastic separator had broken and the usb was shorting out.
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Old 05-25-2012, 05:59 PM
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I hate the newer HP jacks. Too many pins and like on this one you have TWO harnesses, one is a 4 wire and the other is the smaller 3 wire.

If this thing is totally dead, why not hot air it and see if it comes back to life. I'm not saying it will be fixed but if they board is dead you can play with it just for future reference.
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Old 05-25-2012, 09:56 PM
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So the light is on with no load and goes dim or off connected? If it goes off you should measure low or no voltage across the pins you were measuring before. Check the usbs i can't remember the exact symptoms but i had one a while ago where the plastic separator had broken and the usb was shorting out.
The light has never come on. It stays off whether there is a load (jack is connected to mobo) or no load at all (jack is not connected to mobo at all). Is there anything left for me to do (test) before I can confidently tell my customer the mobo is dead? Thanks.
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Old 05-25-2012, 10:01 PM
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Originally Posted by Trusted IT Solutions View Post
The light has never come on. It stays off whether there is a load (jack is connected to mobo) or no load at all (jack is not connected to mobo at all). Is there anything left for me to do (test) before I can confidently tell my customer the mobo is dead? Thanks.
Sorry I misunderstood I though you were talking about the light on the power supply block.
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Old 05-25-2012, 10:16 PM
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Originally Posted by NYJimbo View Post
I hate the newer HP jacks. Too many pins and like on this one you have TWO harnesses, one is a 4 wire and the other is the smaller 3 wire.
I tested for power on the four wire harness only. Should I test the three wire harness as well? As far as hot airing the board...I don't have a gun or a rework station. I plan to get one (station) though.
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Old 05-25-2012, 10:19 PM
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Sorry I misunderstood I though you were talking about the light on the power supply block.
I just re read my OP and I def wasn't clear enough. I was referring to the light on the jack itself.
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Old 05-25-2012, 10:30 PM
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I just re read my OP and I def wasn't clear enough. I was referring to the light on the jack itself.
In theory the light on the jack is supposed to be an indicator that positive is getting to the motherboard and its being fed back to the jack positive connection on the LED. On most LED jacks the neg line of the led is a local loop back in the harness. Having said that I have some HP jacks that show the LED on even if you connect the AC Adaptor to the jack/harness assembly without it being installed onto the motherboard. Why the f-ck is that ?

I have to wonder why the laptop makers like HP and Dell just keep changing everything, making jacks so complicated and when something fails nobody really has a 100% way of knowing what the hell to do next. If Sony, Acer, Gateway and other can use two or four wire simple jacks why does HP/Compaq and Dell have to keep expanding. Have you seen the 11 and 13 pin jacks on some newer models ? Somebody tell me why the hell they exist ?
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