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Xbox 360 red lights issue

A few days ago (just in time for Christmas break) my Xbox 360 started crashing and then gave me 3 red lights, indicating a hardware failure. This is really lame, since I just got hooked on Forza 3, and now I won’t be able to play it over my break from school and work. Thanks Xbox.

I looked up the reason for the red lights, since I can usually find a way to fix stuff. The consensus is that the GPU interface suffered a manufacturing problem due to lead-free solder where the BGA solder balls develop cracks over time. Sounds reasonable. The “fixes” seem to either be reballing the GPU (expensive) or a supposed reflow process that just overheats the GPU.

I tried this one first, since there wasn’t much to lose anyway. The theory is that you can reflow the BGA solder balls and restore electrical contact between the GPU and the PCB by just overheating the GPU. I am pretty skeptical that this is possible, as I don’t think a chip is capable of heating itself to the 320+ °F necessary for solder to melt and flow without damaging itself. Transistors tend to flow a lot of current when they get hot, which would likely damage the processor. At any rate, I tried it. It worked for a day. I wish I would have instrumented the GPU so I knew the peak temperature, but I forgot.

So then I tried to actually reflow the GPU. I tried 5% rosin no-clean flux, and saturated the GPU/PCB interface. I preheated the board to 300°F by setting it on a heated stir plate. I had a fine-gauge K-type thermocouple tucked just under the die so that I could measure the temperature. I heated the die with a hot-air station to 420°F over 2 minutes, and then increased to 450-475°F and held for about 30 seconds.

After the board cooled, I put it back together and plugged it in. Still got three red lights. I took it back apart again and did the same thing to the CPU, but still had the same problem. Then I tried again with 30% rosin flux and slightly higher temperatures. Same three red lights. I suppose the board is junk now, but I still am curious why it worked again after heating the board up a little bit from overheating the GPU. It tells me that most of the fixes out there for “reflowing” aren’t actually doing so, instead they are just creating enough stress on the PCB to fix whatever joint is intermittent. For example, one person supposedly reflowed his entire board in his kitchen oven. I’m not an expert in PCB manufacturing, but if the whole board is at reflow temperature, won’t the RAM chips (and most components) on the bottom side just fall off? There can’t be enough surface tension from the solder balls to actually hold the chip in place upside down.

I did some more digging and found out that you can in fact get error codes without video out. There is a lot of good information at xbox-experts.com. I found out that I have a “bridged solder joint/short GPU/HANA”. I wonder if it’s because of my novice “reflow” skills. I can solder with the best of them, but this is totally different. Wish I had started there first.

That’s one of the funny things about modern manufacturing- it makes something hard look really easy.

References:
http://www.altera.com/literature/an/an353.pdf
http://www.altera.com/literature/wp/wp_chmfgrelldfr.pdf
http://www.altera.com/literature/an/an081.pdf

Tags: Electronics, Xbox 360