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  HP zx5070 WXP Home power jack problems 
 
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Paul Randall Oct 03, 2005, 06:43pm EDT Report Abuse
My daughter's laptop won't charge properly and the problem seems related to the power jack. Her first one of this model had sparks flying from the power connector and HP sent her a new one. About a year later, this second one is giving her problems. While diagnosing the problem, HP sent her a second power adapter for it. The symptoms are the same with either power adapter.

With the computer shut down and the battery at any state of charge, you can just plug in the power adapter and the charging light (lightning bolt symbol) in the case will likely come on steady and it will likely charge to completion, at which time the charging light goes out and there is no indication that power is connected to the laptop.

With the computer hibernating, you can just plug in the power adapter and the charging light will likely come on, but blink off every 5 seconds or so, and it takes a long time to charge. While hibernating, you often have to put pressure on the power plug by stuffing something under it to get it to charge.

With the conputer in standby or running and the battery at less than 85% charged, the charging light may or may not come on briefly when you plug in the power source. Wiggling or putting pressure on the power plug may make the charging light come on for a second or so, but it always goes off quickly. With the WXP power indicator in the tray, I can compare the power symbol (AC or battery) to the state of the charging light (lightning bolt in the computer case) to understand what is happening.

With the computer off but charging, and the batteries at less than 85% charged, if you start the computer, the charging light will go off within a few seconds, ie, you can't run and charge at the same time.

With the computer off but charging, and the batteries at around 96% charged, if you start the computer, the charging light will likely remain on while the computer boots up. Charging continues with the computer running until battery state reaches 100%, at which time the charging light goes out but the power indicator in the tray still indicates the computer is running on AC power.

My conclusion from all this is that power/charging circuitry can handle the current for charging the battery OR for running the computer, but not both at the same time, unless the charging current has tapered off, as it might at 96% charge on the battery. But after explaining all this and spending about 12 hours in an online chat session with HP's support, doing things like completely running down the battery, completely charging the battery, trying to run with the battery removed, etc, etc, etc, I'm hoping someone here can help me out.

Questions:
1) Am I correct that the current required for charging tapers off significantly as battery charge approaches 100%? Is there a web page or HP manual that shows charging current vs battery level or that explains the charging process? Does the charging circuitry also monitor supply voltage, stopping the charging process if the voltage drops too low, perhaps due to a cracked or bad solder joint or defective power jack?

2) How do I get into the laptop in order to physically look at the power jack and its connections to the mother board or charging circuitry? I see lots of screws in the bottom of the laptop, but I'd prefer not to get into stuff that I don't need to get into. Are there an online diagrams or instructions or exploded views of the ZX5000 or similar HP models?

I appreciate any help anyone can give me.

-Paul


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Chris McNally Oct 03, 2005, 11:07pm EDT Report Abuse
>> Re: HP zx5070 WXP Home power jack problems
Hi Paul,

Very tricky-I'm afraid the only advice I can give you after you've gone to all the effort to write the best constructed and most informative post I've seen on HWA in a long time is regarding taking the damn thing apart.

It's not the same for all laptops, but much of the time the way to start the disassembly process is to very carefully remove the plastic strip above the keyboard by sliding a very thin screwdriver or knife under it and levering it off. You can then see the screws that hold the keyboard in place, and once that's out of the way you have access to some of the gubbins inside before you start the process of removing screws from the base.

I know from experience that there is very little documentation on the web to help you if you have a problem with your laptop, so good luck with this one.

Regards,

Chris McNally

Moderator - Hardware Analysis
E-mail: chris@hardwareanalysis.com
Paul Randall Oct 04, 2005, 08:11pm EDT Report Abuse
>> Re: HP zx5070 WXP Home power jack problems
Thanks for the info.
Has anyone used the HP Parts Reference Guide CD? Would it be useful to me? It is kind of pricey (60 dollars), but maybe it would have the info I need. http://partsurfer.hp.com/hp-spi/index.htm. Hmmm, it is too late to order for delivery this month - the next delivery date is in Jan, 2006 :-(

-Paul

Max K Oct 05, 2005, 09:32am EDT Report Abuse
>> Re: HP zx5070 WXP Home power jack problems
It really seems like you just have a bad contact between motherboard and power jack. If you completely disassemble your laptop and take the motherboard out you will see 3 pins under the power plug. They go through the motherboard from this power jack. You will need a little bit of liquid flux and a gas soldering iron to resloder them back to the motherboard. Also if contacts are all right than you might need to see if your fuse is ok, are all the mofsets and capacitors in the power circuit ok and so on. To do that you will need some of the proffesional eqiupment like a tester that can test diods or just a professional multimeter. Also if you short two contacts you may damage the motherboard.
Well, I wrote all that just to let you know that if you do not know how to disassemble the laptop than better do not try to repair motherboard yourself. It seems easy (and sometimes it really is) but the risk that you damage something is pretty high. You can't even imagine how many laptops have I got in which their owners just forgot to screw back one screw and it shorted the whole motherboard. Fixing your problem is not so expensive - it would cost 50-70 dollars to do that. You decide is it worth it? I think it is...
By the way - if your laptop is still under warranty than send it back to HP - they MUST take care of it..

--
Send me a private message if you need your laptop repaired! Low prices, high quality!
Paul Randall Oct 06, 2005, 12:28pm EDT Report Abuse
>> Re: HP zx5070 WXP Home power jack problems
Thanks for the info, Max
I agree with your opinion that the problem is poor contact between the power jack and the mother board. Laptops seem designed to fail -- so many plugs and jacks soldered to the motherboard with no strain relief so even the slightest normal movement of the attached cable may cause damage and prolonged jiggling, such as using mapping software in a delivery vehicle, will almost certainly cause damage.

My real intent is not necessarily to repair the problem myself, but to understand and perhaps physically see the problem before I send it to the black hole of the repair community.

Besides the physical aspect, there is the software aspect. HP has lots of good info on its website, but some of it just doesn't make sense, like:

HP Pavilion and Compaq Presario Notebook PCs - Troubleshooting Notebook Battery Power
Update the Keyboard Battery Controller
Test the AC power adapter
Measure the battery duration in Safe Mode
Refresh the Windows power management

What in the heck is the keyboard battery controller and how does its software affect the laptop's main battery?
Is the windows power management a Microsoft Windoes software thing or an HP software/hardware thing? Does it monitor voltages or currents to determine whether to charge the battery? Where can I find info on this stuff?

-Paul Randall

Ken LaDere Oct 06, 2005, 06:33pm EDT Report Abuse
>> Re: HP zx5070 WXP Home power jack problems
The ZD, ZV,ZX series( As well as the twin Compaq models), Are all surfacing the same issues.. (Too much heat and eventual failure).. HP, Manned or purchased a DC jack from Foxconn origionally. This looks gold visibly (center pin the laptop).. These were breaking off at the rear of the positive lead due to flex and heat issues. The upgraded jacks on their replacement boards generally last for about 4-6 mo's.. (Silver center pin and a hard wire lead).. These overheat and cause a ring crack, FET's in the supply line failure, AIC failure, as well as other issues. We do NOT suggest contacting HP on these repairs as the board will fail again.(At your 300.00 expense and then 600.00 for a board) We have had customers with extended warranty's and three board replacements send the unit to us to hopefully kill this issue. This is not an unusual problem and shoud be rectified by hp. See this note and link and read happily..http://www.howtofixcomputers.com/bb/ftopic73146.html good reading all...
Ken

Ken LaDere
http://www.ikenfixit.com
231.539.8779
231.758.0529 (message)
ken@ikenfixit.com


 

    
 
 

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