So you may remember that when the graphics card in Nyx failed, I mentioned that it might be repairable? Well, the repair I alluded to is to attempt to fix any failed solder joints... by baking it in an oven at 200°C for 10 minutes. Seriously! There's no end of forum posts and Youtube videos suggesting this as a fix for failed graphics cards, particularly nVidia GeForce cards around the 8800GT mark (the Internets suggest that nVidia skimped on the solder and/or underfill quality for BGA chips, and the thermal stresses from repeated power up/down cycles eventually break one or more solder joints), and most people who claim to have tried this have reported success.
The physics for this checks out as well. Essentially what I'm trying to do is emulate the reflow soldering process used to make the card in the first place, which when you get down to it is basically "bake it in an oven", but with much better temperature control. The aim of reflow soldering is to heat the card up to the point at which the solder melts and flows - much like with a soldering iron, but heating every solder joint in one go - and the temperature needed to melt solder is around 200°C depending on the particular alloy used. Real reflow ovens are ridiculously expensive pieces of kit, but there's many alternatives - SparkFun use a skillet, while Mike's Electric Stuff suggests using a Sainsbury's Basics toaster (removing the pop-up mechanism recommended unless you want a SMT desolderer...). So it's not too far-fetched to imagine doing this with an ordinary oven.
Anyway, first step was to prepare the graphics card. After removing the heatsink I needed to clean all the old thermal compound off the card.
This just requires patience, a pack of cotton buds, and some isopropyl alcohol or similar (I used a bottle of isopropyl alcohol-containing lens cleaner). And for a change, I've got an action photo!
Eventually I got the remains of the old thermal pads off the RAM and power regulators, and cleaned the huge splodge of thermal compound from GPU itself:
Most integrated circuits are hidden inside a plastic package, but GPUs (and CPUs) are often exposed. That's the back of the actual silicon die there, cleaned up to a mirror finish.
Next, preheat the oven to 200°C. While that's warming up I made a foil tray for the graphics card, with a small foil ball in each corner to balance the card on.
Then I stuck it in the oven for 10 minutes. Once the timer was up, I turned the oven off and opened the door, then let it cool down slightly for another 5 minutes. That seems to be what most people online have done, give or take a minute or a few degrees C.
Mmmm, toasty, with a wonderful smell of hot solder.
None of the capacitors have detonated (always a good sign), so now I just need to wait for it to cool down, put the heatsink back on, reinstall it in Nyx and see if it works.