Saturday, January 9, 2010

DV9000 Power Issue

This HP DV9000 arrived with power problems. Difficult to diagnose simply by looking at the bottom side of the board (which faces tech when opened). When the power cable was disconnected from the board an obvious scorched connector was noticed. This 4 pin plug supplies power to 2 sections.

Not wanting to be too verbose, I will simply say that all 4 connections to the motherboard are needed and when one pin is scorched and oxidized, it cannot provide adequate current or voltage. So the plug end was replaced, and the interior of the jack was cleaned of carbon residue from the scorching.

The number of issues with this unit, makes for a days work. Power issues, broken LCD issues, SATA connector, USB port all on one machine. Everytime I fix one issue another pops up. And the customer wants it fast, but at a cheap price. When does it end?


  1. Thanks you for this blog. The topic of DV9000 is very interesent. I have a DV9000 that has a problem with power part of motherboard. One days when i whatch video, the pc was stop promply to work. When i press start key, didn't start, there was not power. What is the problem ?

  2. Generally speaking without having the machine in front of me it usually is the chip on the bottom, in the corner AO4407, check with meter to see if it is shorted.

    If not check the other side right of the power plug, and check FDS6679 [or AO4413 is same]

    With +[pos] on pins 1,2 or 3 and -[neg] on pin
    5,6,7 or 8 the resistance should be more than 300Ω if it is less than that in both directions, replace.

  3. Here's an interesting note, on similar issue.

    When I was replacing the MAXIM quad output power IC [MAX8743A] it shorted out the same MOSFETs listed above. But it may had been my fault since I thought I had disconnected the power from the unit. This made it short when the MAX8734 was being soldered in.

  4. Hi technician;) could show yourselves on an image the rooms(parts,plays) which are to be verified(to verify)? What are the values which the multimeter has to post(show)? In what calibre is it necessary to put him(it) to measure it? You think that it is what parts which it is necessary to change? Good courage and thanks to you. Friendly...

  5. The blog is generally intended for skilled technicians, and not of much use to those that do not know some electronics. I will try to be courteous.
    Generally a MOSFET is simply a diode that allow electricity (or current) to flow in one direction. IT is turned on by a gate (usually Pin 4)

    When testing with a meter- set to Diode mode.
    If the meter shows infinity in both directions it is an OPEN mosfet (like an open fuse).
    If the meter shows <50 Ohms in both directions - it is shorted.

  6. Can you explain how to test a maxim chip such as 8734? It looks like mosfets can be easily checked with a DMM, but how do you check that square or rectangle maxim chip? They don't always have holes in them :(

  7. One more concern I had. Say I find bad mosfets, is it as simple as replacing them? I'm worried that if damage has spread somewhere else on a motherboard, that it will just burn out the new mosfets.

  8. DV6000 No Power - Blue DC Block lights..

    Low ohms

    181 ohms - 7636 (By 8724)

    51 ohms - 7636 (ENE)

    274 ohms - 6679 (by opposite side of CPU socket)

    Replace all? This version of the board uses an intersil SMPS controller. How would I test it? ISL6236

  9. Rob I am not sure of your diagnosis. If you have lights, generally the DC is good. Since I had not noticed the symptoms or description anywhere.

    If the lights on the QuickStart bar is on, DC is ok.

    If the charge light comes on when battery plugged in, DC is OK.

    IF NO DC/NO Lights - check the FDS6679 next to the 4pin POWER IN. Or the AO4407 under it on the bottom side.
    If the MAX8734 is shorted like I did, other MOSFETs may fail too. But I think I had created that short, by the MAX8734 moving while I forget to disconnect power. Purely my fault in that case. RARE for additional chips to fail.

    No Video is usually caused by:
    1: The nVidia Chip
    2: The South Bridge Chip (next to network card)
    3: Failed LCD

    If #1 there will be no external video, no POST
    If #2 system may work, but no WiFi or USB
    IF #3 system works normally on external monitor.

    1. Please forgive in advance if I intrude here. I am no professional. However I have been given a non working HP Pavilion DV9500 (dv9680ed) for my young son and with nothing to loose I am attempting to find out if it's worth rescuing. It appears to be in reasonable condition but pressing power button gives nothing, no lights apart from blue ring around power socket and no noises. I have checked adaptor, disassembled and checked power socket and lead to motherboard, both ok.
      I have found this blog after Googling and have been reading with interest. I would like to check the items mentioned FDS6679 and AO4407 but my motherboard is visibly different to the example given in photo's elsewhere in these blogs for the power in section. It has an INTEL processor and I remember seeing in one of the posts that the INTEL board is different and wondered if anyone can point me to the appropriate items to initially test given the total lack of power. If not then my thanks anyway for the contributors as this blog must have helped many people.

  10. Well, the problem is that the blue LED on the DC block lights, so I'm not worried about the 6679 / 4407 by the power connectors being bad, but the unit still fails to power on.
    The next logical step I thought to do was test the resistance from source to drain of any other mosfets I found - and that is when I found those other mosfets with what I believe to be unusually low resistances.

  11. Rob: the Blue light on the power plug will stay on even it is not connected to the motherboard. It is simply a power light to indicate the Adapter works, not the laptop.

    Generally the previous 2 MOSFET mentioned are the culprit. Though rarely it could be the AO4812 just below the ribbon connector for the power switch.

    RE: the drain/source resistances- these may vary by MOSFET used. The ME series Mosfet has a different resistance than the AO Mosfets. Though both will have infinity in one direction.

  12. One more point that is needed to mention.

    The ribbon cables will break. Expecially if continued removal and insertion is done. They sell them on ebay but at outrageous prices. A substitute and more flexible temporary cable could be used from a Gateway MA2/MA3/MA7 touchpad if you have a dead one lying around. That is what I use during diagnostics- saving the customers cable from breaking during repairs.

  13. No.. I know that the LED stays on. I power on boards by shorting the leads on the motherboard with two small screwdrivers - I know which leads turn the board on.
    Usually when there is a plain 19V short - the blue LED will go out, but turn right back on once you remove it from the board. That's not the case here - the 6679 & 4407 are fine. Something else is causing the board to not power on, but it is not from those to mosfets. If it were, the blue LED would likely not power at all. I just repaired one like that last week - replaced the 6679. But this one is different. The blue LED stays on even after connected to the board. The short must be somewhere else - but not on the 19v rail.

  14. Rob: 1st which pins are you shorting to get it to power on? Then also the power switch is controlled by the AO4812 (or ME4920 on newer boards). You should have about 3.4v at pins 1 & 3 on the source, and same on the drain (pins 5,6,7 & 8). The voltage travels up to the pwr button and when closed the voltage should drop to 0v.

    If not then the button is bad, or the ribbon cable is bad.

    If it does drop to 0v it may be the Dual Ch. Mosfet (AO4812)

    Datasheet then enter AO4812 in the search box.
    If that doesn't solve it, try replacing the MAX8734- it is a 28 pin quad power output device

  15. I should have mentioned that this is a dv6000 board. With the 9000's, I remember seeing those two mosfets you're talking about - one by the power button connector and one by the wifi switch. On this board (459565), I don't see either. As far as maxim chips, it just has the multichem and pwm. Instead of an 8734, they chose to use an ISL chip on this board. I guess my next step is to find out which mosfets control the power switch on this model....

  16. I have a board which is not powering on when on mains, connect a charged battery is powers up fine, display etc. Have tested against a working board and I'm not getting the gate voltage on the Mosfet (one in corner-PQ3) on Pin 4 of 28V, but zero volts. This seems to be generated by a 25V Zener diode - its this likely to be the problem or is it a shorted capacitor on this gate dragging this down.
    The charging circuit doesn't work on this board, aswell as not switching on when on main - but as said works fine with a charged battery.

  17. Adam: I am not familiar with the EU units and their voltages but should be the same as Power IN (about 18.5-19v) not 28v. But my guess would be the resistor that drops the current down on the gate could be the culprit or a shorted cap. Also check the 2 fets by the FAN along the top edge as the battery connector.

    With power and battery disconnected, check the AO4407 and the FDS6679 see if they are shorted. Otherwise you may be looking at replacing the MAX8734. Not often the small zener's blow, but it can. usually it's the FETS or the Quad Power chip. If the PQ3 is the AO4407, it gets the gate power from the power connector, and dropped by a resistor. Pin 4 should have the same voltage as pins 5,6,7 &8.

    Rob: here's a thought- try turning on the unit with the remote control. If that works, you have a problem in the section behind the ribbon cable (got one of them today). Powers on with remote but not with power button. So having to go through that circuit now.

    Also check FETs in the diode mode of your meter, to see if the current or voltage only flows 1 direction.

  18. I connected the food(supply) on the computer, the blue del in the entrance(entry) of the cable ignites and a small noise comes of the environment(middle) of the computer as second of a clock. I wanted to say to you that before defusing(unsettling) him(it) can be it inspires you the other thing(matter)? I go tested the rooms(parts,plays) which you say. Thank you;)

  19. Emre: I am not understanding the question. I speak/understand many, so try your native language. French/Dutch/German/Spanish/Portuguese -

    What country?

  20. Je parle français. Je vouslais dire que la led à l'entrée de l'alimentation s'allume lorsque je branche le câble, et à ce moment là, il y a un petit bruit comme les secondes d'une horloge, et quand j'appuie sur le bouton de démarage, rien ne se passe. Quel est éxactement le calibre que je devrais mettre sur le multimètre ? Merci ;)

  21. Do you know what I can use to substitute a pair of 6676 fets?

  22. Where is the 4407 ? I do not manage to find it ??

  23. EMRE: The is no one spot to put the meter. You have a shorted capacitor. You have to find which one is shorted. It is not easy.

    N'est unique tache pour mettre le mètre. Vous avez un condensateur court-circuité. Vous devez trouver lesquels est court-circuité. Ce n'est pas facile.

  24. Emré: L'article AO4407 est sur le fond sous le connecteur de puissance.

    Rob: Have you searched the manufacturer? Have you checked Digikey or Newark Electronics?
    it is a 30V N-Channel 14.5A FET

  25. If I change directly the AO4407 or FDS6679, the pc can be restart to work or not ?

  26. Il n'y a pas de 4407 ni de FSD6679 malheuresement j'ai testé les valeurs des autres parts près du connecteur de puissance, je trouve des valeurs entre 90 et 122 ohms. Mais certains n'affiche aucune tension.

  27. EMRE: If that was the problem. Check to see if the items are shorted.
    Si c'était le problème. Vérifiez pour voir si les articles sont court-circuités.
    With meter check resistance of Pin 2 and Pin 6 both directions. One direction should be about 500 Ohms, the other should be infinity.

    Avec la résistance de contrôle de mètre du contact #2 et du contact #6 les deux directions. Une direction devrait être environ 500 ohms, l'autre devrait être infini.

  28. Dear technician, I've had another problem with my Pavilion DV9000. My laptop doesn't switch on, so I disassembled the mainboard and I saw one of the components blown. Could you tell me the name of the 8-pin chip (under black ribbon) on the left of battery connector? It has blown and I can't read it yet. Many Thanks

  29. pls, my dv6000 shows dt it is charging when i boot but stops after 4 rounds and left wt 0percent. The batery is o.k and charges on a friend's laptop. It is hardware 'cos i hv updated bios and installed another o.s and power management. It does nt charge even wn it is off but d blue charging light is on. I hv searched 4 d power cct schematic bt cld nt find. The a.c adapter is o.k. I cn wrk on hardware electronics. Can u pls help?

  30. I have a DV9010us that is very similar in the photo and description to the one you have here.

    Its symptoms are, no power, no lights, etc. I have meterd the mosfets and I seem to get a short on both of the A4119N parts across the gate and source.

    I also meter a short across a fair few of the power diodes in both directions. What would you suggest I try first, right now I am inclined to remove the A4119N fets, but I do not have access to any reflow/smd gear.

    Thanks in advance

  31. whoops, I meant I get a short across the source and the drain in both directions.

  32. I have got a dv9000. No voltage on Power button, max8724 doesn't open PQ61 (AO4430). ACIN Voltage on max8724 pin10 is ok, but there is no ACOK# signal so PQ64 is closed so PQ61 is open.

    I opened PQ64 manually but then the blue light on power connector goes out, it seems that there is something shorted behind PQ61.

    Is there someone who knows something about this behaviour?

    I have another dv9000 whith a broken backlight, there is no PWM Signal (backlight brigness) from either the ene superio (kb3920) or the gpu.

    Is this caused by a defective kb3920? Why is the Backlight PWM signal routed to the gpu too?

  33. pls help... i have a dv 9000 mb that is dead , no led light , and no power

  34. Catalin,

    If the blue ring around the DC jack does not light up you may have an issue with your ADAPTER.

    That ring will even light up if the cable assembly is remove.

    If you were meaning there is no lights on the panel, it could very well be:
    1: the ribbon cable connecting to the panel
    2: the previous thread with the AO4407/FDS6679
    3: BIOS Chip
    4: Wrong Power Supply (s/b 90w)
    5: CMOS Battery dead

  35. hello, the ring is lighting, the led that indicate battery charge is not light, and when i press the power nothing my mb is with isl6236 an dmax 8717e

  36. Catalin: Then the problem may be in the charge section. You did not indicate what you had tested. Intead of immediately jumping to the large scale ic's check the ciruit paths.

    If you are not a tech it will be even greater to analyse your problem.

  37. the max8724e is charging battery but is no led to signify ,,the isl 6236 give the 3v and 5v ,, on the g1 connector i have 3v but when i pres g1 to gnd nothig no power but i have the esentil voltage on my mb ,,what i need to do ,,to measure on my mb

  38. Hello.
    I've an DV6000 that can't turn on. The DC input ring ligth is on when insert the AC adapter, but no more lights are on when I push the power on button in the laptop or in the remote control.
    I've tested the two mosfets AO and FDS as you say before, and two are ok. I've ~3v in the power on switch too.
    When I plug the battery, its not charging and no light turn on.
    What can I do?
    Thank you very much.

  39. Hello.
    I have DV6500 that can't turn on.The DC input light ring light is on when insert the AC adapter but and battery light is on but laptop can't turn on.I've found on motherboard mosfet FDS6676AS who is in short conection when i desoldering its ok but contacts of FDS6676AS is still in short conection without mosfet and i found 330 79vc D who is in short conection but still same problem.I dont tested MAXIM(8717E) who is closer to FDS6676AS.
    What is the problem someone help me.
    Sorry for my english.

  40. Hello.
    I've got DV6000. My symptoms are:
    1. after pressing the power button, fan starts, LEDs glow as normal, no video signal on LCD or external monitor
    2. after 10 seconds it shuts down, means LEDs and fan off and blue LEDs on the front panel blink once
    3. pressing the power button now results in the same process as in the step 2, but it runs only 1 second and there is no blink after shutdown
    - AC adapter is OK; HDD, optical drive, wifi, keyboard, touchpad and LCD panel are removed or unplugged

    What's your opinion about this symptoms? Is there any possibility to remove them? Thank you very much for your answer.

  41. Ondrej: Issues Depends on the model. But it sounds like a corrupted CMOS or BIOS Chip. Try to clear the CMOS and restart.
    Clearing the CMOS involves holding the power button down for 30 seconds and plugging in the DC power. The panel will flash for about 5 sec then turn off. The next time the system is powered up, it will re-read the CMOS from BIOS. And should work, if not focus on that area.

    Use the remote if available to power on, just in case the AO4812 under the power ribbon cable is shorted.

  42. Hi Mayo, I really hope you can help me as this is one of those things that I cant get me head around. I repair laptops that have the most common of HP DV/TX series issues (no display, 3 beeps, no wifi, etc), now I have a had many customers bring laptops that either power up for about a second then turn off or completely dead or power up then turn off after about 10 to 30 seconds, these are all DV6000 series that have nVidia MCP67M-A2 North Bridge (Geforce go 7200). I don't know if you have come accross any of these issues, please let me know!

  43. Hi Erin. dv9000 with “Plugged in, not charging” problem. Depleting MB caps and reconnecting power changes battery status to "Fully charged." Any suggestions?

  44. My apologies, Evin, for repeatedly misspelling your name! Haven't had my second cup of coffee yet. That's my excuse and I'm sticking to it! BTW, the laptop runs fine on AC (and battery, if partially charged). Just refuses to fully re-charge unless reset as mentioned above.

  45. Answering the easy ones first:

    Larry Check to see if the 4407/4430 has ~19v on both Source and Drain. Then should have voltage on the gate to pass the power through. Over near the corner by the fan there are 2 FETs that should also be checked.

  46. I have a dv9000. the PQ61 (AO4430) is crisp, has some compatible to put in place? I fear one of the dv6000 PQ3 (PG9BP 6679AZ, can this be?

  47. Evan, I checked the suggested items with a DVM on diode-test and found nothing unusual. There is a diode (PD23?) beside the 4407 (Q4) that is cracked but tests as good when cold. Not sure if it is a cause of effect. After practice-soldering some QFN 28s (like the MAX8724e is) and noting a 300C max temp rating for lead soldering, I chickened-out and suggested the client just use the laptop always connected to the AC Adapter.

    Now that I've read and watched a good tutorial on soldering QFNs, at, I'm more confident I could replace them successfully. However, it just didn't seem worth the risk until I've practiced more.

  48. Alexandre- the AO4430 is the newer replacement, the previous chip was AO4407.

    Alpha and Omega

  49. Good morning Mr Mayo,
    strange problem on HP DV9000 laptop;
    unit starts and is full working,but when powered off, it wan t restart until dc jack is unplugged and reinserted.

    Tested FDS 6679 and AO4407 and seems ok, may be a capacitor not discharging?

    Thanks Marcello








  51. Thanks for the useful info. I have a dv9000 that died while I was using it; just went blank. No DC jack light. Checked the resistance and was essentially zero. Pulled the FDS6679 and AO4407 from the board and the DC jack was on again. The FDS6679 was shorted (AO4407 was OK) and I replaced it. Now I have power to the board, but it draws high current (>5 amps - using a current limited supply during testing _ have used this supply on this computer before, so I know it works) on 20ms pulses about every 800ms. No key functionality, keyboard lights or fan action. Any ides where to look from here? Thanks.

  52. Seems like it may be something like a shorted cap in the front end. Check the large ceramic caps. (Brown, non-polarized) there is a bank of 4, and a bank of two, depending on the board.

    You did not mention model or if it was Intel or AMD so I assume it was AMD. If it is an AMD with the diagonal nVidia chip (such as DV9500 or 9700) it may need a reflow. Some point under GPU may be shorted, or not draining to reduce current draw.

  53. An update on the shorted power frontend...
    It was a shorted cap - C27. I found the schematic at and was able to isolate which parts are in that circuit. Without the documentation it would have been impossible as my ohmmeter goes only to hundredths of an ohm and was not able to narrow down which part of the board had the short. The power bus dives into the board layers and pops up in the strangest places. By removing the isolation inductors (one flew across the room and was never to be found - I pulled spares from a junker board) and current sense resistor, I was able to isolate the various functional areas. Once narrowed down, it was the second cap I pulled. Looked just fine, no visible difference from the adjacent good caps, but was a dead short. The laptop's on the bench now running a test loop and charging the battery. Pulling 2.8 amps @ 19v from the current limited bench supply.
    Success! Thanks for the blog, it got me started on digging into the thing; wouldn't have had an idea where to start w/o your helpful hints.

  54. I have a dv2700 here that someone has attempted repair on the DC input section, it's toast, there's so many botched solders it's impossible to even begin troubleshooting with my limited abilities.

    It runs OK with a charged battery so since I was going to repair it for myself and I never move my laptop from the desk I was thinking about powering it via the battery terminals.
    The battery is rated at 10.8V.
    Do you think this is feasible or are the battery control signals going to mess me up?
    Great blog :)

  55. Hi,

    I have problem with dv6000 motherboard, I can start the laptop on power adapter, but I cant on battery. I have tried my battery on other laptop and it is working. Also the laptop is not charging the battery. Can you help me?

  56. Filipe: there are hundreds of variations of the DV series laptops. Though they look the same the internals are considerably different. Without a model number I can only speculate that it would be a chip AO4407/4427 on the Power In section. If it is an Intel motherboard the problem is in another place.

  57. hey everybody,

    i have a dv9000 model with amd cpu. the battery is charging, but i can't turn on the laptop. he's starts for a second and power off immediately.

    what can i do?

    thanks for your help

    1. What model DV9000? that is only the series number.

  58. I spend countless hours trying to fix dv9000 "blue power button light won't light up" problem. Replaced motherboard, multiple cables, etc. The issue appears to be simple - tiny HP Pavilion DV9000 POWER SECONDARY BOARD 3SAT5MA0001 was bad. Someone also refer to this part as Lid Switch Board. I just wanted to throw this information in this very helpful blog in case someone else runs in to the same issue.
    Once it was replaced, computer powered on without issue.

    1. Thanks SolonPC- I haven't had a failed power button board. Usually it is the ribbon cable. But LED's do blow sometimes I guess.

      There are two diamond shaped pads near the power ribbon cable that can be shorted to turn on the power. <| |>

  59. i have dv 9000 which is not power up ...only Ac jack light on other thn that no light .....plz help

  60. hi sir mayo! i have a dv9720 with continuous power cycling (on / off) but after i reballed the MCP/northbridge, i resolved the problem..

    however, when I turned on the laptop, it passed POST (i can even edit BIOS setup) but cant get into OS.. a little cursor (dos type) blinks at the upper left for about 2mins then it will say "Missing Helper."

    it can't boot to DVD drive either for os installation/ 3rd party tools,,

    i already tried swapping the hard drive and dvd drive with a known good one but to no success.

    maybe you have an insight with this scenario,. what chips to check?

  61. Dreadnaught:
    I have not experienced that problem, though I suspect that the BOOT sequence could be set to boot to floppy. Another suggestion is to remove the PC Card port and test. Check the PCI controller/ENE chip. Missing coil or cap from the reflow process.

    And since I am not sure of if it was done correctly It could be any number of chips.

  62. I have laptop HP DV2500. I have blue light by power cord connector. I do not have any Led Lights on front panel. These 3 lights are off. Laptop do not want start. I try change CMOS battery for new one. I try also hard reset. Nothing help. Could someone help me with some other advice. Thank you.

  63. The light on the side of the DV2000 series power plug light will light even if removed from the motherboard. it is only an indicatior of the adapter having power. If you have no power going to the system, then check the pair of mosfets AO4407. To see if they are shorted or open. If they are open no power will be passed to the motherboard. If they are shorted, the power supply may short and the ringlight will turn off.

  64. Hallo Mr Mayo,

    I have a DV9500 (dv9670ed) When i plug the charger with battery connected the blue charging light is on, when i press the power button the power light gives one quick flash and the charging light goes off. nothing else happens the unit is compleet dead. To get the power light to flash again i have to disconnect the charger and remove battery and connect it again, then the power light can flash again when i press power. The Blue ring is always on, and i have connected a difrend charger butt al the same. Where is the best place to start looking? (it's a intel board with Nvidia GPU) Thanks in advance!

  65. Remco - The blog does not assist in repairs, it simply reports the repairs I have done. Usually the intel boards that exhibit that problem is to check the 4914 Dual Mosfet in the power section.

    Note: The blog is under moderation, simply because I cannot answer all the questions from thousands of techs and non-techs that have problems.

  66. --------------------------------------------------------

    Hi, i have repaired my dv9500 following the process below... It took 15hours for me with motherboard schematics to find and fix the physical damages.

    If the laptop doesn't switch ON but you have the right blue led adapter ON, it could be this:

    ===>> SHORTED CAPS which OFTEN destruct ICs or Diodes, so the current can't flow across the board...
    If you experiment the "dv series dead power unit" issue follow this steps:
    -take multi meter
    -take self control
    -take your laptop motherboard
    -find FDS6679 (4413), FDS6900, AO4430 (4407) and MAXIM8724 data sheets

    1-check these big orange or brown ceramic caps: PC32, PC33 ,PC 7, PC 9, PC 10
    if one or plus are shorted or crisp, replace or just remove (risky but that's what i did)
    2-check if FDS6679 (4413), FDS6900, AO4430 (4407) behave like healthy MOSFET Transistors if not REPLACE
    3-check if PQ3(FDS6679) and PQ61 (AO4430) gates voltages are between 10-20V if not check all the ten diodes (PD xx) that are close around the 4-pin white power connector, if one or more is open in both ohmeter directions (for me, PD16, ref. ch501h-40 ) : REPLACE by another general purpose Diode or ch501h-40.

    PS: at each step, check MAXIM8724 voltages, pin 1 must be 5V, and you have to read around 28-30V when mesuring at PR183 resistor (next to PQ61). Check often all mosfet gates voltages and try to run laptop at each step.
    Feel free to paypal donate at "" if it helps you.


  67. I don't know if you're still reading this page. I dissasembled a DV9000 for exchanging the cooler and on reassembly the laptop doesn't start; there's no power led turning on. Do you know the pinout of CN4 (before the power on cable strip)? I hope only that cable is affected.
    Thank you!

  68. i have a dv9010us laptop with a power issue. the blue light @ power plug lights up when plugged into wall. i press power button to turn it on and the blue lights on the top panel turn on for approx. 1 or 2 seconds, then turn off. im technically savy with electronics and electrical testing and have a dmm. what should i check? its an amd processor with nvidia graphics chipset. also the wireless card doesnt work either.

  69. Hi Mayo,

    Thanks for your useful information you give. I have a DV2000 and have many thinks. 1st when I turn on the power button comes nothing, than I turn off and immedtley I turn on and press F2 and starts. Always connected with the a/c power.

    Can you help me please.


  70. Hello, I am testing a FDS6679AZ, pins 1,2, 3 (-) to pin 5,6,7,8 (+) results in 460. But pin 4 (-) with 5,6,7,8 is 1 (infinity). Is this normal? or corrupt?
    Thank you.

    1. hi GEKO
      yes that is normal, consider the MOSFET as a DIODE with a switch (GATE). The current or voltage (depending on MOSFET Type) can only pass when the GATE is turned on/powered. One direction will have Resistance, the opposite direction will be infinity.

      N-Channel and P-Channel MOSFETS have complementary/opposite directions.

  71. Dear technician. I have a DV9339us that powers up just on battery even if the power adapter is connected. I checked the mosfets and the 2 circuits (PQ47 and PQ52) on a good motherboard and works fine. Is it possible to be from MAX8724?

    1. I doubt it. The Mosfets could be shorted and still power on the other board. The problem is between the power in and the charge circuit. Usually a shorted cap or a dual mosfet AO4712 (or ceramic caps in that area) since it is an Intel board.

  72. HI MR MAYO....

  73. Hp dv9700 no power,i hear a Ticking noise from the board. I have 19v in PQ61 on pins 5,6,7,9 but in pins 1,2,3 i get from 0 to 0,08V and pin 4 from 0 to 0,23V i have replace the pq61 but i have the same problem. On pr183 i get 28v and on pr182 i get 0 v. Even from a charged battery is not receiving power.can you help me?

    1. kokoras: What you have is a classic shorted capacitor problem. The short is keeping the unit off, as well as exhibiting the ticking sound. That ticking sound is the cap trying to charge up, but shorts before it can.

    2. Thanks for the info, how can find the bad capacitor? can i test it on the board or must removed from the board?

    3. You can test the cap in circuit, with a meter. One direction will show infinity, and the other direction may show high resistance or infinity. But - if the cap show low resistance in both directions it is shorted/ In this board is typically the caps in the power in section.

      The board could work normally with a charged battery, but not allow DC-In to run or charge the laptop.

    4. Hi, i have replace the pc33 and is powerering up ok but is not power up from the battery only from the charger. The battery is full charged and is ok i have tested in other laptop. When i have the battery and the charger connected windows showing that charging the battery but always showing 0%

    5. I replace and the pc9 - pc10 capacitor and is working ok, is charge the battery.
      Thanks foe your help!!

    6. Sure- Glad you finally got it repaired.

      Consider the donation button, that's how it works. Often I never find out if a repair is successful and feel as if the blog is not of much help.

  74. Now you have to check the MOSFETs at the front DC IN. And the MAX8734 to see if it is defective. Not an easy item to test. The MAX8734 controls the levels that is displayed in the taskbar tray. The shorted cap could have also shorted the Quad DC Power Output chip (MAX8734) or the other chip that controls the linear display.
    The MOSFET on the bottom of the motherboard near the DC IN controls the charge. When battery in it will have voltage on both sides, when battery is out only voltage on one side.

    I can't tell you the numbers because I don't do too many now. And you did not mention the number of the board.

    I've tried to help as much as I could, but I cannot fix it or further diagnose via the internet.

  75. you must put Google AdSense ads to make some money, i think people will click the ads to help this blog to live for ever

  76. Hello. I have a dv9000 with no power up problem. On batery conector i have 0.7v, but there it must be 3.3v. Some adices?

    1. see Important Parts on DV6000/DV9000 there you should be able to find info on where the voltage to the battery connector comes from.

  77. good day,

    im glad i saw this thread, i hope you can help me with my dv6000. it powers on but no display, as well as the fan does not rotate, upon dismantling, i saw that the PQ38 AO4812 is busted/cracked/burnt. what could have probably caused the 4812 to bust? im afraid that if i replaced it, it will just bust the new 4812. TIA

    1. It could have simply shorted, or received a surge. Sometimes they just cannot handle their rating, and fry. Since it is a dual-channel mosfet, it would take some research to find which source was the culprit also. Check the other MOSFET's that feed it. If one of them is shorted there is your problem.

  78. I have hp dv9000. What is the number/name of the biggest ceramic capacitor? I need a replacement.

    1. Not fully understanding the question. Caps are marked on board ( C83 example)

      Or post picture

  79. The ceramic is next to D0628. I cant get the number and cannot insert pic.

    1. Go to G+ and add me, or send email to me



I cannot repair laptops for you via the internet, I can only answer questions related to posts. This is because I have not had experience on every motherboard that is out there. Bear with me.

If you do need it repaired. Contact me for quote (US/CDN Only)

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