Note: Sorry for the lack of more pictures in this article, most of my data was lost when my laptop was stolen
My gf bought a "refurbished" laptop off eBay. What they didn't mention was that the battery was shot, the hard disk was on its last legs, and most annoyingly for her (as a music lover) the soundcard didn't work. It would not initialise either in Linux or Windows (in windows it didn't even appear as a device). After much hassle we decided not to bother getting a refund, and decided to work on getting this one to work. The other problems were easy to sort out, but the soundcard was not so easy.
On desktop PC's replacing a soundcard is really no big deal, you can usually just put a PCI sound card into the slots and be on your way. But laptops are different, they are not user-upgradable in this way. They have a single mini-PCI slot (used by the modem device on this laptop) and mini-PCI based soundcards are generally geared towards embedded systems, with a price tag to match. Our only realistic option was to get a USB soundcard off eBay and use that. So we did, we bought a cheap Chinese USB soundcard and it worked well (actually, it worked flawlessly under Linux, kept stuttering and crashing under Windows - oh, how things change!). This was all well and good, but the USB soundcard dangling out the back of the laptop was prone to being stressed by movement and carrying of the laptop and, sure enough, the card's connector broke off.
My gf was already not happy with the fact that the laptop's internal speakers didn't work (logically), so when this happened the opportunity arose to try to install the USB soundcard into the laptop, and integrate it with the volume/mute controls and the internal speakers.
First task was to take apart the laptop and see if there is any space that could fit in the soundcards PCB, and sure enough, there was a free area under the cardbus slot (This area looks like it for the infrared optional module, which was not standard on this laptop):
Unfortunately there was not enough space to put a USB hub, but for this to work we have to make use of one usb port. Thankfully the Thinkpad has 2, so despite this we could do it and still have one port available. We decided on using the side USB port because, being recessed into the case, it was harder to fit things like USB-keys into it, so was of less use. Below is a picture with the cables for the PCB already soldered to the motherboard USB port (you can see the old USB plug in the picture, as well as the original case.
After initial testing, we removed the phono sockets from the soundcard as well. The soundcard was full-duplex with speaker out and line/mic in, which was exactly what the original was, so the laptop sockets were a perfect match.
We removed the old connections and soldered wires directly to the phono sockets on the motherboard:
There were a total of six wires to solder: Left, right and Ground for both input and output sockets. When this was done we soldered the other ends to the soundcard PCB and tested:
Success! Worked well first time :)
All that was left to do was to epoxy it into the laptop chassis. I also replaced the green LED with a red LED which had longer leads. Below is the setup after epoxying (the epoxy was not dry yet, so it was being kept together by the rubber band). I ssh'd into the machine to test it out.
Once the epoxy dried, I reassembled the laptop, here it is from a side view with the soundcard LED indicating use:
And with the laptop booting:
I can say that this was a success. Not only do both sockets work, but the internal speakers work as do the speakers attached to the expansion base when required. The input socket also works as does the built in microphone. I really was surprised at how much actually worked. The only thing that didn't work was the up/down/mute buttons, which I was able to bind in software to the soundcard anyway.