DV4-1255dx - No Video, Blinking lights on topside

DV4-1225DX
Needle in a digital haystack - numerous problems
Damaged Coil Side view




Problem described as Memory Slot Not working & No Video


Since I had never seen this unit come on, with memory in slot 1 or slot 2 there was not much I could do other than thoroughly inspect the system fisrt.


Damaged coil Top View
1: Found that a coil under the PC Card slot was broken.
    Replaced and Test - No Fix
Replaced












When peeling back the plastic near the Video connector- looking close I notice a cap is stuck to the plastic. Very small ceramic cap that was hardly noticeable without magnification.


Now- Where does if come from and where does it go?  What is it's purpose?






Under magnification, I view the area where the smaller components are and
see evidence of solder or tampering.  This appears to be the location of the missing/stray cap.




  
Since this is a multi-step repair...


Back to the work bench to see if the problem is fixed now.
Stray cap found near video conn.
Location of cap
Missing from pad
Replaced Capacitor

Comments

  1. elficheTue Jan 17, 06:41:00 PM EST

    think for info grited morroco in africa

    ReplyDelete
  2. UnknownThu Jun 21, 10:30:00 PM EDT

    Hello,
    I have a Hp DV4-1225dx

    My problem is that when I power it up, it comes on and stays on, but I get no video and I get a continuous blinking of the caps and num lock light. I am a computer tech, but this project has me baffled. I ordered a new motherboard and it is doing the same thing, I switched out Memory chips(ram), and it is still doing the same thing. I even tried different Cpu's on both motherboard's, and I am still having a problem.

    Help me please

    ReplyDelete
  3. HoosierFri Jun 22, 09:01:00 AM EDT

    You may have a defective touchpad or add-in peripheral. You should always test the board on the bench first. Without anything connected.
    Then do a visual inspection, carefully lifting plastics and have plenty of light, because they can remove parts from the board.

    The DV4 series reverts back to manufacturing problems. Switching over the the ATI video from nVidia simply swapped problems. Many caps and resistors on those boards have weak solder joints, from either flowing them too fast or contamination on the solder pads.

    Levi- you did not say what the blink code is. 1 Blink, 2 blinks or what. I will be checking over some of the DV4's that I have done and see what I can write up.

    ReplyDelete
  4. UnknownSun Jun 24, 08:57:00 AM EDT

    Well when it blinks it just continuously blinks, I know that means power failure, but that's not possible when I added new bios bat, new battery, new adapter plug. One of the boards I just found out has a burnt capacitor, but the other one I'm still having the same problem.

    You say its the touch pad, when I plug it up i just plug in the aux power, and the power button and dc jack. then turn it on and get the same thing, I don't even plug up the touch-pad.

    I'm about to send this bad motherboard back that I just ordered and was already having a burnt capacitor. Should I get my money back or is this board a possible fix?

    ReplyDelete
  5. HoosierSun Jun 24, 09:29:00 AM EDT

    You may want to notify the seller, and inform him that it is doing the same thing that your dead board does. Sometimes they write their ads on eBay so confusing that it said that it was a parts/repair board. But if the ad says that it is working, return it. Not knowing the capacitor that is burned, I cannot say if replacing it would fix it.

    ReplyDelete

Post a Comment

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)

Popular posts from this blog

Important parts on DV6000 and DV9000 series

Image
These are important parts if you are looking for shorts or opens on the DV series. This image shows the location of the FDS6679. A common cause of shorts in the DV series. When the power supply is plugged into the laptop and it shorts out/turns off it's usually caused by this MOSFET being shorted.  Plainly stated. You plug the adapter into the DC Jack and the Blue Ring fails to light up, and the Power Supply shuts off. Giving no power to the tip. To reset adapter, unplug from AC (mains) and wait 15-30 sec. Then plug in again. The adapter is not damaged, since this is how it is protected. These parts do not determine charge time or per centage. The FDS6679 only closes to complete Positive circuit.  The AO4407 only closes when the battery is plugged in. As a test- Check the voltage of the Drain side (pins 5-8) with AC adapter and no battery - you should see 0 volts.  When you contect the battery you should have 10-14v depending on DV6000 or DV9000 series. IF the AO44...
Read more

DV9000 Power Issue

Image
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?
Read more

Tips on Testing MOSFETs

Image
Imagine the flow direction Source to Drain This is how I test FETS  What I will try to do here is to provide a little insight on how to test  MOSFET's in circuit the easiest way I can think of. Essentially the FET acts as a switch, and the GATE either opens or closes the switch. When power is supplied to Pin 4 (usually the GATE) it will either open or close depending on the type of MOSFET it is. The arrows shows the direction for reference when using a meter to test.   Setting the meter in DIODE mode. On the N-Channel FET place the NEG lead on Pin 6/7 and the POS lead on Pin 2/3. You should get a reading of some value ~100 to 500 or higher. Imagine the flow direction Drain to Source On the P-Channel FET place the POS lead on Pin 6/7 and the NEG lead on Pin 2/3. Again you should get a reading of some value ~100 to 500 or higher. The reason I say pins 2/3 and 6/7 is ...
Read more