[HD2 General] booze_pistol:
Update on more success

So I have been busy working on this HD2 situation. I finally broke down and got my SMD rework station. I went with an Aoyue 968. Absolutely love it, it has made my life so much better. Also purchased 3 K-type digital probes. The best investment ever. they were $11.66 ea shipping and all on eBay. Just search "New K Type Digital Thermometer Temperature Sensor"

I have also been able to obtain 3 more HD2's. I was talking about it to some people at work, and they knew people, or friends who had them with this problem. I am happy to report that I have been able to fix all 3 of the phones. Well I broke one of the tiny cables to the camera flash unit on one, but all 3 phones are working like new again after the repair.

With the new equipment that I got, and with some truly accurate measurements , I have made some discoveries that hopefully will allow people to have a higher success rate with this issue. I was able to remove the CPU from the failed oven HD2 bake. The cpu release from the board at around 238C. In multiple tests of that board, and on that cpu the solder begins to melt at between 213 -218C. That is a very important discovery for all TMOUS users. This is the "sweet spot" if you will for repairing these phones.

No matter what heat source you are using, you need to achieve 215C at the CPU /board level. My 968 may be set at 320C to 360C, but that is not relevant. It is the temp that the board itself is that matters in this process. Using the Ktype probes after you properly calibrate them will allow you to get an accurate reading at the board. Going slightly higher than the 215C might work, but it is not necessary so far in my experiments.

With all 3 phones I repaired yesterday I used the hotplate as a bottom heater for the board. I set it to 185C , and let the board preheat for 5 minutes. Using the Aoyue 968 with 18mm square netted nozzle, I start it at 320C. VERY IMPORTANT. These are temps of the equipment, not the temp of the board. Using a Ktype probe on top of the board at the cpu, and one Ktype probe on the bottom of the board at the cpu, attached with aluminum tape, I am able to see the board level temp very accurately. When it reaches 215C I keep it there for 1 minute. Turn off top and bottom heat, let it cool completely. VERY IMPORTANT. keep the board perfectly level, do not bump it or move it at all.

This worked on all 3 phones. I am certain at this point it will have a high success rate ongoing. Grant you the equipment used not everyone has. My main point I am trying to contribute here is no matter your heat source do not exceed the 215C mark. buy yourself one or more of the Ktype probes I mentioned. Calibrate them and use them to make sure of the temps. It is not necessary to keep that 215C temp for more than a minute, two minutes max. You are trying to revive cracked / cold solder joints, anymore time than that you risk allowing the solder joints to merge and ruin the process.

To those who have nothing more than an "ELECTRIC" oven to use to fix this issue. Here is my two cents. Get a Ktype probe! It is a must. Preheat the oven to 225C. Attach the probe to the cpu with metal tape, put the board on a ceramic cup in the center of the oven, make sure it is level, allow the lead for the probe to come outside the oven to the meter. The probes I mentioned have heat resistant cables. Watch the temp on the meter, when the "CPU TEMP" , I repeat the CPU TEMP reaches 215C time it 1 minute, then turn the oven off and let it cool completely. This method allows for no preheating of the board, but placing it in the preheated oven it will rise to the temp gradually anyway. No more than 3 degrees per second is perfectly fine. Little chance of a board this small flexing and causing damage. I do not recommend this at all, but if your gonna try it in an "electric oven" my opinion is this is your best chance at success. The temp probe is the best friend you will ever have in this procedure.

Well I am off to look for more phones to repair. :D