[HD2 General] booze_pistol:
This is how I fixed my HD2 this weekend (fixed so far so good)

1. An electric hotplate / griddle

2. Thermal probe

3. Small screws / mounting hardware

4 LUCK!

So I have an electric griddle / hotplate, not sure what everyone calls them. It has a digital Temp readout on it. Make great pancakes! Until this weekend I never saw it as anything more than that. It occured to me though that it was a heat source. A relative steady heat source that could perhaps be used in my endeavor to reclaim my HD2. It has a maximum heat setting of 500 degrees Fahrenheit. Sorry I am American and Celcius just confuses me so all temps mentioned in this post will be Fahrenheit. Out of curiosity I turned the hoplate on maximum, waited till the beeper went off to say it had reached it's temp, took my thermal probe and the surface temp measured 494 degrees. It did not fluctuate more than +/- 2 degrees for five minutes of testing. I found this encouraging.

To my wifes dismay I took the griddle into the garage made some measurements of the motherboard, and drilled two holes in the hotplate. Using two 1/4-20 bolts, 6 washers, and two 1/2" wide x 2" long x 1/8" thick pieces of metal I fashioned a mount for the motherboard. Bolts through the bottom of the hotplate, 2 washers on the top side of the hotplate, then the metal peices, then another washer and a nut. I was able to attach the motherboard to the hotplate securely. The gap between the board and the hotplate is between 1/8, and 3/16". It wasn't exact becasue of the washers. I used metal tape to cover the board except for the CPU. I mounted the motherboard upside down, CPU facing the hotplate.

At this point I was concerned, I did not know the exact temp to were the solder balls might release. If they did then the chip would simply fall onto the hotplate, and that would definitely not be good. So I decided to turn the entire hot plate over, thereby making the the motherboard right side up. I suspended the hotplate off my workbench with some metal pans I had used to store spare parts in. At this point I was very skeptical. Wondering if the hotplate would even work upside down? Wondering if all the heat would just go up? I decided to proceed though figuring if the temp didn't get high enough I would be were I started, with a phone that worked for a few minutes and reboots. So what the heck right?

I turned the temp dial to 300 degrees. Let it stay there for five minutes. Turned up 50 degrees, waited 3 minutes, then up another 50 degrees, waited anotrher 3 minutes. Continuing till the hotplate was at it's maximum temerature. I then let it go for exactly five minutes. I could not get my thermal probe to the CPU, The gap was too small between the motherboard and the hotplate. So I don't know what the temp was at the CPU? Was it the 494 degrees, minus 10-20 degrees for the casing on the CPU. No way of knowing what the temp was at the board / solder level. Sorry there was just no way of getting these readings. After the five minutes at maximum temp, i simply turned the hotplate off and let it cool down normally.

I turned it over, removed the mount for the motherboard. Removed the metal tape from the board. Skeptically I reassembled my phone. I turned it on, it booted up, as it often will when its been off for a while. I immediately went to Youtube, started watching random video after random video, Then I played transformers, 1 and 2,back to back without any issues. i have been using it for two days now, pretty much non-stop. I will start movies, and just walk away, come back and check on it. So far, it has not froze one time, it has not rebooted one time. I am reluctant to say it is FIXED, because i keep expecting it to stop working. it is hard to accept that it might have actually worked. I am in the process now off taking it back apart to fashion a heatsink similar to facdemol's from the first post in this thread.

I DO NOT ENDORSE ANYONE TRYING THIS. It may have been pure luck on my part. Could be a complete fluke? It is yet to be determined. All I know is that my phone is working like it used to FOR NOW! I have another HD2 that I will be trying this on if this one lasts. I was in experimenter mode when I did this one so I did not even think to take pictures of the process. Wish I had. If this one lasts and I try the other one I will document the entire process.

I have thought for some time that it is most likey the solder joints around the outside of these chips that are most likely damaged. The resin used to secure the chips to the baord, keeps those areas secure to the point of not allowing the chip to flex enough to absord the expansion of the solder. Has nothing to do with anything, just an observation. For now I am happy , but nervously waiting to see if this actually has fixed my phone. The addition of the heatsink will give me more confidence. A week of steady use and no more problems and I will begin to breathe a sigh of relief.

Thanks to facdemol and everyone for there contributions to this problem with the HD2. Thanks also for the continuing efforts to find solutions for the average guy without a workshop full of IR rework stations. If it were not for this board and this thread I would never known it was a thermal problem and would have just sold the phones for parts. So Thanks to you all.