Archive for August, 2008

How to Repair a HP nx7300 Laptop

How to Repair a HP nx7300 Laptop

Niels Bohr once famously said that an expert is “a person who has made all the mistakes that can be made in a very narrow field”. Baring this in mind, it’s fair to say that in the last week I’ve become an ‘expert’ in HP laptop repairs.

Here’s what happened:

Monday morning, back from holidays. Within five minutes of turning my laptop on for the first time in two weeks, it suddenly shut down. There was no life out of it whatsoever. No lights, no noise, no laptop. Panic hadn’t yet set in but it was on its way. After about 10 minutes of frantically hitting the ‘on’ button the internal fan kicked in and a couple of LCD lights started to flash. I thought I was getting somewhere. I figured maybe it was just a temporary problem that had managed to fix itself somehow.

I couldn’t have been more wrong.

Thirty seconds after the fan kicked in, a puff of black smoke came out the side air vent followed by the dreaded smell of burning silicon. It was toast. My treasured laptop had become nothing more then an expensive paper weight in the space of about 15 seconds. At this point, panic had properly set in and I was seriously worried.

Out of Warranty

The first thing I thought of doing was ringing HP. I’ve used their support in the past and they’ve been really helpful. But after a quick check, they told me my laptop was out of warranty (only just) and that it would cost €90 to assess the laptop so they could give me a quote for the repair. I didn’t need to spend €90 to know that my motherboard was toast, the smell was all over the office. So I had a decision to make. Would I fork out the money and let HP fix it for me or would I try doing it myself, save some money and learn something new in the process? For me, that’s a no brainer. I would try it myself.

Dismantling the Laptop

Before ordering a new motherboard, I wanted to take apart the laptop to make sure that’s what the problem was.

Have you ever taken apart a laptop? It’s not as easy as you might think. At first I tried it without a guide. I managed to take out over 20 screws but I still couldn’t open it up. I decided I needed some help, so after a little Googling I discovered that all HP laptops have their own service manual which explains step by step how to replace any component, and the order in which they need to be replaced.

Here’s the document I used as a guide: HP nx7300 Service Document (PDF – 4.2Mb). Without this I had no chance.

Turns out that before the motherboard can be removed, you also have to remove:

  • Hard Drive
  • Optical Drive
  • Bluetooth Module
  • Keyboard
  • Thermal Plate
  • Fan
  • Heat Sink
  • RTC Battery
  • Switch Cover
  • Display Assembly
  • Top Cover

Over the next two hours I slowly worked my way through the guide, dismantling the laptop piece by piece. There were over 70 screws (15 different types) and 25 components that needed to be removed before I could get the motherboard out. It was painstakingly slow. Here’s a quick photo of what it looked like fully dismantled:

A Fully Dismantled HP Laptop

Finding the Damaged Chip

Once the motherboard had been removed it was pretty easy to see what had happened. One of the microchips on the board had been completely destroyed. I could even see where the flame had scorched the casing on the pc card slot. Have a quick look at this image to see what happened:

A Damaged Microchip on the Laptop Motherboard

At first, I considered trying to replace just the chip rather then the entire motherboard. I mean, it seemed a shame to have to replace the entire board when only a tiny portion of it was damaged. But after some more thought I decided it would probably be best the replace the whole thing. I didn’t know what else had been damaged and my skills with a soldering iron are clunky at best.

The Replacement Motherboard

I used the HP parts website to price a new board which cost €266 plus VAT and included all taxes and delivery charges. They had the board in stock and said delivery would take 3-4 days.

So, 3-4 days later I received a shiny new motherboard in the post, ready to replace the damaged one.

Here’s a couple of shots taken while I unboxed it:

Unboxing of the New Motherboard (Part No. 441094-001) A CLose Up of the New Motherboard

Fitting the New Board

To fit the new motherboard, I just reversed the steps taken to dismantle the laptop. Each part went in, one after the other. It was a little harder putting it all back together because I had to make sure I was using the right screws each time (there were more then 15 different types), and that I left nothing out. Having to fit it all together is pretty tricky, but by following the service guide I managed to get it all back in without too many issues.

During the reassembly, I had a second laptop (same model) which I used to read through the different steps and make sure I got it all right. Here’s a few shots of the reassembly. If you look closely you should be able to see the corresponding manual page on the screen at the right side of each photo.

Motherboard Fitted Top Cover Fitted

Display Screen Fitted Internal Components Fitted

The Components Explained

While working on something like this, you really get an appreciation for just how well designed these things are. Everything has been thought of. All the components fit perfectly together. It’s like a jigsaw, only much more elegant.

Here’s a quick top down view of the different components in the laptop:

Laptop Components - In Place

The Final Test

After the last screw was tightened and the last component was clicked in, I finally had the laptop back in one piece. All I needed to do now, was turn it on.

Assembly Complete

So, I held my breath and clicked the ‘on’ button.

The fan kicked in, the screen flashed on, and I could hear the wonderful sound of a hard disk being accessed.

It had worked.

My laptop was whirring quietly away as if nothing had ever happened.

I was thrilled. My gamble had paid off, and I’d learned a lot along the way.

The Benefit of Hindsight

I think the cause of the problem was dust and overheating. Not surprisingly, the damaged chip was located very close to the main processor, which generates a huge amount of heat. It was also very close to the fan and heat sink, where dust can build up.

I have a habit of using my laptop in bed, and surrounding the laptop’s air vents in a duvet. This, I now know, leads to overheating and ultimately, component damage.

To extend the life of my laptop and the new motherboard I’m going to do two things:

  1. Clean it regularly using compressed air (this stuff is awesome and you can get in Maplins).
  2. Stop using it in bed.

I think these two small changes should keep my laptop in good shape for a good few years to come.