Motherboard replacement

Hi All,
I think/know that I have to replace the motherboard on my notebook, which is an HP Pavilion dv5-1054TX.
1. Can anyone tell me how I can find out the model and whatever info is needed to order a new motherboard?
2. Does anyone know the pinout or internal schematic of the battery HSTNN-Q34C for this notebook ? (This is for trying to connect an external power supply directly instead of the battery).
Thanks,
Boris.:confused
HP Pavilion dv5-1054TX, Vista

 

Hi

Laptop motherboards are proprietary, which means likely the motherboard in your laptop was only used in a few different kinds (or maybe just that kind) of HP Pavilion laptop. It will likely cost you SEVERAL HUNDRED DOLLARS to replace just that motherboard. It would probably be more cost effective to get a new laptop, and sell the one you currently have on eBay for parts.

However, if you're really wanting to keep that laptop, I suggest contacting HP.

EDIT: Doesn't look like it would be as expensive as I would've guessed... here's Google shopping results for the motherboard:

http://www.google.com/#q=HP+Pavilio...AQrQQwBA&biw=1920&bih=859&fp=87dedf703ab49d09

 

It's easiest to search for the A/C adapter by using your make/model, which is a HP Pavilion DV5. A/C adapters are very simple electronics and in my experience generic versions work just fine, though you still must be sure you trust the seller.

Here is the generic adapter for your laptop on ebay for $7.50:
http://cgi.ebay.com/AC-Adapter-Char...=Laptop_Adapters_Chargers&hash=item2c597279eb

Here is the genuine HP adapter, again from ebay for $18.50:
http://cgi.ebay.com/Genuine-HP-Pavi...=Laptop_Adapters_Chargers&hash=item2a0c8721c3

Before ordering either one, flip your laptop upside down and look for the writing which states the input amps (A) and volts (V). The voltage will usually be 18.5V or 19V, and the amps required by a laptop typically fall somewhere between 3A and 5A. Whichever adapter you decide to buy, it *must* be exactly the same voltage, and must be equal to or more than the amps the laptop calls for. Both the links I gave list adapters supplying 18.5V 3.5A, but if you shop around you may discover others with different Amps (and possibly different Volts), so be warned.

 

Thanks Guys for your reply.
I have to start from the beginning.
This laptop works perfectly on the battery until it runs out. I think, if the battery could last for ever, the laptop would never stop working. But, if I remove the battery and run the computer on the battery charger, it runs only about 4-5 minutes and the power just cuts off. After that, when the computer is warm it will keep cut the power with about 1 min. interval. Looks like the charger... But the charger has been proven to be OK.
Another think. When both the battery and the charger are connected, they both work for about 4-5 min then the charger cuts off and the computer runs on battery until the battery runs out. Then the computer goes into hybernation, cools down and the charger connects itself and happily charges the battery. Then the story begins again.
So, part of the power circuit which converts the 19v of the charger to about 12v for the computer to run and charge the battery gets hot and cuts off the charger (external power).
Now, repair the motherboard is almost impossible particular not having the schematics.
The question is: to replace the M/B or not to replace. Sounds like Hamlet.
As to the the second question. I have the adapter, as stated above. What I want is to connect an external power source of 12v directly to the battery terminals. The question is: which 2 out of the existing 8 pins I am to use? That's why I need the the pinout of the battery or the internal schematic of the battery.
Thanks,
Boris

 

Hi

As 94dgrif already stated, you need a very specific power adapter that has volts and amps regulated per the laptop specs. Laptops CANNOT be connected to desktop power supplies.

 

Hi,

Just a thought - Just had this one. Laptop runs half speed on battery thus cooler. Mine just needed the heatsink assembly cleaned out. This one was easy. Most are difficult. Not likely that the AC Adaptor is at fault. Does it charge the battery with the Comp turned off? Google for how to clean the fan and heatsink.

Good Luck, Jim

 

To answer your original question: I don't have the schematics (and they're not freely available on the web). If you are electronically minded, you can simply remove the battery and test the terminals the battery normally connects to the laptop to find the volts and amps each is being fed from the power supply. You can then flip the experiment by wiring the battery to the laptop terminals (so you have some distance to work with) and repeat the test to determine which terminals supply what from the battery. Generally there are longer/wider terminals that supply the power, and the others are possibly just sensor information and grounds.

If you're not electronically minded, don't do it! In which case let's troubleshoot the problem.
1. Look at the writing on the underside of the laptop and the A/C adapter - does the A/C adapter output the same volts and amps that the laptop wants to input?
2. Are you getting brownouts on that circuit of your house? Does the breaker ever flip or do you have a lot of electronics on the same line, with flickering lights etc?
3. Remove the battery and power up from just the A/C adapter. Toggle or rotate the point where the A/C adapter connects to the laptop - does it power down?
4. Are there other symptoms of the motherboard being bad?

 

I concur.

 

Hi guys.
I am greatfull for the help. Yes I am an electronic engineer-elecronicly minded that is. But it doesn't mean I know everything. Far from it. Checking the battery to find which pins are 12v does not tell me for shure which is which. There are two pairs of 12v. but they are not the same. Lithium batteries have a protection circuit inside the battery, so it is possible to bypass it and endanger everything around it. Again, if I can not find the circuit digram, I woudn't try at all, for common sence sake... Common sence? Common sence is to drop it alltogether and buy a new notbook! Yes, but where is my face then? The notebook belongs to my grandson who untill now believed that his grandfather can fix everything. Well, not exactly, but he does believe it.
Again Guys, thanks for your help.
I am going to clean the heatsink. This does make sense to me. Athough, if the heatsink is the problem, then I would expect the computer go into hybernation rather then cut the power?
But I am still going to clean it.
Thanks again.
Boris.

 

The heatsink stops the CPU and GPU (Graphics Processor Unit) from overheating. When either overheats they work a lot slower, and in the short term will cause a crash, but in the longterm can break them. Some motherboards (that's where it is right?) have a thermostat and when the CPU gets too hot, it shuts the computer down to prevent damage. I haven't ever witnessed this happen though, so I don't know if there is any warning beforehand.

Please do go through and answer by 4 sets of questions though - they really could help find the cause.

 

Thanks 94dgrif ,
Sounds right to me. Will see and report back.
Boris
94dgrif
Senior Member

94dgrif
Senior Member

 

Hi again Iggy,

Most laptop batteries I have seen have the polarity marked and + and -are usually at the extreme ends of the contacts. I really don't think what you have in mind is going to work. The innards of the battery are a simple thermal cutout in series with the battery. Also for laptops made in the last few years there is a "Micro Processor" in the batt that is monitoring all the cells. All those other pins on the batt connector are for communication between the Micro and Laptop. If those signals are not correct it will just probably say the Batt is dead or such. Not really sure. Hope this helps a little.

Good Luck, Jim

 

Thanks Jim.
You do make good sense. I have done nothing yet, but I am going to.Will report back.
Who ever said that retired people have much time !
Thanks again.
Boris

 

Hi again Boris,

Thanks for the feedback. I'm assuming that the AC Adapter does charge the battery. If so there is probably nothing wrong with the adaptor. There is no chargeing circuit in the adaptor. It only supplies the Voltage to run the Comp. The Comp and the Micro Processor in the battery case make up the charger. I also haven't seen the schematic/logic for the battery. My experience is from takeing the bad ones apart. The Comp's processor has the temp sensor for the last maybe 10 years. As far as I know it does just shut down. Hibernation would have been a good idea.

More Luck, Jim

 

Hi Jim.
As I said before, you make a lot of sense.
I agree, the comp.works half-steam when on battery- that's why it works fine on battery, but something gets hot when on mains. I still believe, there must be a regulator on the Mother Board between the charger 19v and the battery 10.8v (charging voltage about 12v-12.5v). Then the 12v will have to be regulated down to 5v for most part of the computer to run.
The computer is yet again in pieces on my bench. The heatsink is clean, the fan is OK, but the problem is still there.
Sounds like I will have to admit defeat. I think it gets too much even for a stubborn old mule as yours truly. The only thing left is the MoBo replacement. I am still tempted...
Anyware Jim, thanks a big lot for your input.
Best regards,
Boris.
Melbourne, Australia

 

Hi Boris,

"Stubbon OLD Mule" - I'm way past that OLD state and my main hobby is fixing things (Anything) someone else has given up on. Sounds like you are pretty much the same.

Good Luck and thanks again for the feedback,

Jim,
NorthWest Chicago and displaced Rebel.

 

Well Jim,
here you are as "bad". Glad, there are others, who understand. And what do you mean saing "I'm way past that OLD state ". Are you, say, over 72 ? In that case I bow my head to you.
Best regards,
Boris.

 

This all sounds like a heat issue - I think you already knew this, but I didn't understand it from what I had read until now. Some laptops will have settings which will engage an energy saving mode when disconnected from the A/C adapter, to prolong the duration the comp can stay on, but at the cost of performance. As a test you could navigate to your power settings, and set your computer to act exactly the same when connected to an A/C adapter as it does currently when powered by battery alone. If that does indeed fix your problem, then this is actually just a symptom; probably of your CPU overheating - take a vacuum and some canned air to your fans.

Another way to diagnose a heat issue would be to use a CPU temperature monitoring utility. Alternatively you could connect your A/C adapter, go to the BIOS settings, and just sit on that screen (ideally the screen with the temperature monitor if applicable). If it shuts down there, then it is an electrical problem not a heat problem.

To test the adapter, take a multimeter to it and make sure the adapter is passing steady voltage. You could disconnect the battery and adapter and use the resistance gauge to check that the A/C jack of your laptop isn't oxidized, though that wouldn't really explain the symptoms you're experiencing.

Finally, please do tell us the labelled voltage and amp inputs of the laptop (written on the underside of the laptop), and the voltage and amp output of the A/C adapter (written from the underside of the A/C adapter).

 

This is the first thing i was going to suggest, this simple test will tell you if its an issue with the brick and rule out the charging circuit on the laptop. From experience, if its power circuit inside the lappy, and you have soldiering experience its a med level difficulty fix, more on the hardware side. Internal charging circuits do fail and sometimes have issues.

 

Hi Guys,
Had to have a break from the Conputer, orders from the chief commander.
Now, to answer some of your, Guy's questions.
Yes, "the brick" is proven to be OK, the problem is temperature related. The CPU is set to react at 70 Deg C, but the temperature does not reach 60 Deg C.
The battery voltage is 10.8V so I think is the computer, but the charger is 19V.
By the way, Colemanguy, fixing a PCB as you sagested, is easy enouph.What is hard without a schematic diagram is the diagnostic. As you, probably know, it is not the replacement of a 3 cent worth of a resistor the expert charges $500 for, but the knowlege which resistor to replace.
Anyway, I am about ready to give-up and order a new motherboard. But the chief has more urgent plans for me for now, so see you in a while with a report.
Best regards to all of you.
Have a nice Christmas. Also have a good and peaceful year.
Here in OZ the turkey is already being digested .
Boris.

 

Hi All.
I am back home .
Having enough time to ponder on the motherboard saga, I am throwing in the towel. After all, enough is enough.
Accepting defeat is not sweet, but one has to swallow it sometimes.
Thanks for all of your help.
Best regards,
Boris.