My laptop is getting on a bit now and has started developing a few problems. Primarily I am experiencing overheating, with the fans running at full power and various a few other niggles. This is my illustrated guide for HP laptop disassembly. It is based on the ze5400ea model but should be similar for any HP pavilion disassembly. I am approaching this with four main objectives:
- Clean fans and exhaust airways of dust to improve airflow and cooling
- Investigate poor wireless performance
- Investigate faulty power switch
- Investigate broken floppy drive
This procedure will certainly invalidate any warranty you may have on your product. This guide is produced through experimentation and is in no way endorsed by HP or Compaq. Always follow correct electrical safety procedures. Do not undertake this task if you are uncertain about dismantling/repairing electrical components. The author, Tim Trott, accepts no responsibility or liability for any damage to hardware, loss of data, injury or anything else. Whilst every effort is made to document as accurately as possible, this is a guideline only and any work you decide to carry out, you do yourself. Basically, if you mess up it's your fault.
Background to my HP Laptop Repair
I am experiencing ever-increasing fan noise, due to the processor overheating. A quick inspection of the fan grille shows substantial dust build up and I assume that this is restricting the air flow and the thermal efficiency of the cooling mechanism.
I am also experiencing a poor wireless performance, while one minute it will be connected perfectly fine then, without warning, the bandwidth will drop to 1mbs (still with good quality and strength) and will not communicate with anything. When I disable the connection and re-enable a few networks are discovered, but not mine. I have to keep dis/re-enabling the connection and eventually it will pick up the signal again. This could remain stable for the rest of the day, or 5 minutes. As a temporary fix, I am using a PCMCIA wireless card which has functioned perfectly fine.
The power switch is very detrimental about when it works, mostly not working. I have to use the quick function buttons to activate the laptop. Feels like the switch is Pepsified (that's covered in Pepsi).
Finally, the floppy disk no longer accepts floppy disks. They go in part way but do not 'clunk' down to the heads and spindle, rendering it useless.
After over three years of ownership my laptop is now out of warranty and as such now begins to show signs of breaking (typical!). Technically there is nothing wrong with the laptop, the specs are high even by today's standards (2.8GHz Pentium 4 Processor, 512MB RAM, 54G Wireless) so rather than rush out and buy the latest model... what harm can be done by attempting to fix it?
The first thing we need to do is remove the Battery and AC connector to prevent any electric shocks. Next is to remove the Hard Drive and store it safely to prevent the risk of data loss. The hard drive can be removed by unscrewing three screws on the underside of the laptop. One screw is covered by a rubber grommet.
Next, remove all the screws from the underside and rear of the laptop. There are no screws under the memory and expansion panels and there are no labels covering any screws.
Turn the laptop over and open the screen fully. Just above and under the Page Up key is a little cut-out where you can prise the cover off with a flat head screwdriver. It will then unclip and can be removed (you have removed the screws on the hinge at the back?) Be very careful of the two wireless antenna connectors, they are fragile and you don't want to damage them.
This gives access to four screws holding the keyboard in place. Unscrew these and you can remove the keyboard from the laptop. You will need to unplug the connector from the main board.
You will need to unscrew the wireless antenna connections and disconnect the screen DVI connection as well as the floppy drive ribbon cables (mine had Panasonic written on it in large letters) There is a small and a large one near where the keyboard was plugged in.
More screws, these took a while to find the correct ones. There are three at the top and one down a little shaft. With everything unplugged and unscrewed you can now remove the top part and the screen from the base. There are a few clips at the front which can be prised off.
With the cover fully off it is clear that there is a substantial amount of dust build-up inside. There are clumps of fluff on some of the chips.
My next task is to remove the heat sink from the processor so that I can clean it out. The system works using copper heat pipes to direct the heat away from the chip and to disperse it near the side of the case using copper heatsinks and fans. This allows for a very flat and compact method of heat redistribution. When removing and fitting the heat sink, please note the tightening sequence of the screws. By following this sequence it will improve the contact area and quality of the contact, the same as when fitting a cylinder head to a car.
Having removed the heatsink it was obvious that the metal fins were totally clogged up with dust. Taking it outside and blowing compressed air into the fins and fans removed most of the dust, and a paintbrush helped with the rest. The difference is obvious between before and after. Hopefully, this will help with the overheating issue. When reassembling the heat sink to the main board I cleaned both surfaces with isopropanol and I used a little Arctic Silver to aid with thermal transfer. Please also observe the correct sequence if you decide to do this.
Reassembly of the laptop is the reverse process with nothing major to report except two connections. You may have noticed that the top half and bottom half were joined with a small solid connector, the top half having pins and the lower half sockets (see picture, connector is located near the optical drive). These need to be aligned properly or you risk damaging the pins. Don't forget the function button panel connector - its easy to lose it when you put the cover back on. Wireless connections should also be carefully fed back through the cover and reattached.
Reducing Fan Noise Further
Mindi has kindly written in advising me that HP offer a BIOS update that will reduce fan noise. Since my fans are still noisy (although much less now) I had a look at this link. The BIOS version to fix fan noise is version KH.F.15, and since my BIOS is KH.F.08 I thought it wouldn't hurt to give it a go. I don't usually update BIOS software (if it isn't broke, don't fix it), but if this can help reduce fan noise I had to check test it out.
This BIOS update was tested on my ze5440ea model, the update process was absolutely perfect and as easy as downloading the file (1.6mb) and running it. I would make sure that you check compatibility from the HP website before running the update, and it looks as though the flash updater itself check compatibility before starting.HP Bios Update Software
Once downloaded, simply run the executable and it will self-extract and launch the flash program. From there it's just a case of following the onscreen steps. If successful the system will reboot and you should have an Intel logo as well as the HP logo as it boots up.
First impressions are that the fans are less noisy, I have determined that there are 4 fan speeds in use: 1) Off (only if using outside or in very cold rooms (AC). 2) Quite running (seldom heard) 3) Normal Noisy running and 4) Going into meltdown.
It seems that in this update HP hass changed the normal running mode to quiet running by changing the temperature threshold. The BIOS flash works! Thanks for sharing this tip with us Mindi.
Summary and Conclusions
My first task was to clear the fans and heat sinks from dust to reduce the noise from the fans running at full speed constantly. This was achieved by removing the heat sink assembly from the processor and blowing compressed air into it, further, a paintbrush was used to remove stubborn particles.
This has had the desired effect, with the noise greatly reduced. This should also improve the performance of the laptop slightly as well as lengthen the lifespan.
I could find no cause for the poor wireless performance, all cables intact and all contacts clean, however, the card and contacts were cleaned with alcohol and reseated and it does seem to be performing a little better. Update on next day: Back to usual - non-working state. No idea why this laptop can't connect to wireless LANs one minute and not the next.
The faulty power switch I have put down to a bad design flaw. The switch is illuminated by an led from below. When pressed, the switch rock on a pivot point to depress a microswitch to the left of the button, therefore the button must be depressed not in the centre, but off to the right, in order that the microswitch is activated. Poor design, but knowing this does make it easier to operate by pressing the right edge of the button down and to the right.
Floppy drive shows no visible cause of an error and remains broken.