Hey! No problem, of course I can explain what I did for other amateurs like me but, I am sure its not the best way to do it.
Please read all of it as I explain some stuff towards the end.
What I used:
I used a semi-pro grade stripping heat gun, SKIL brand to be specific with a smaller attachment head. Although the brand doesn't matter (as long as quality is preserved), what matters are two things:
1. Heat-control: It allows you to set the heat, not exactly but, to some degree.
2. Heat-check: it makes sure that the heat coming out is consistent and that it doesn't burn out the gun itself.
Also used a 6 inch - 150mm tweezer and some soldering flux.
The way I did it:
I used a small tweezer and held the part to be unsoldered so that the tweezer didn't get in the way of the heat gun and I wasn't going to burn myself from the heat bouncing back from the board. Holding the part with the tweezer, I lightly pulled on the tweezer so that the board was about 1/8" - 3mm up in the air. This way when the solder melted the part would separate and with the help of gravity the board would just fall a short distance to the table and nothing else would move. I held the heat-gun over the part, short of 2 inches - 4cm high and started waiting, in about 15-20 seconds, the part came loose in the tweezers and the board just fell 1/8" - 3mm and rested on the table. No other part was desoldered or had even moved.
After the part was off, I took the replacement part, dipped its legs in flux and put it back where the old part was, watching out for the direction marking circle on the IC. I had enough solder left on the board so that I didnt need to add any new solder and could just reheat the board and that would do it.
I pressed on the part with the tweezers, ever so lightly, just enough to make sure that as soon as the solder on the board melted it would catch on the legs of the new IC. I put the heat gun on the new part and waited, this time a little shorter as the board was already cooking from the last heating. In about 8-10 seconds, the part fell down, ever so slightly with the pressure of the tweezers, into the solder of the board and I saw the solder creep up the legs of the IC and knew that it was done. The board was plenty hot by this time, so had to wait to test it, but after a while I found out that it had worked just fine
What to watch out for:
Do not worry about the board getting hot as long as no discoloration occurs. If you see the green plastic (or other color) layer on top of your board turning yellow (or another color), that calls for concern so stop and let it cool down. It means either you're applying to much heat or too quickly. Other than that, the board will get pretty hot, but thats what happens when they originally make these parts in special ovens as well.
The setting that worked for me on the heat gun was medium. For first time users, the gun will seem to be pushing a lot of air, and it is, but no need to worry as the parts wont move from this airflow as it was mentioned before by Steve because of the surface tension of the solder.
The second thing to watch out for is the type of solder that was used by the manufacturer. The solder without lead is harder to melt and it take a little more time (seem way too long) for the heat gun to melt it. More and more companies are using lead-free solder nowadays for environmental reasons so more than likely thats what will happen when you experience it.
Its better to shield close by plastic parts, maybe with heat putty or even unsolder them if possible. The heat from the heat gun, even with a smaller diameter head, has a negative effect on nearby plastics, like sockets or the shrink-wrap plastics on the capacitors. It just melts them.
!!! Don't work on a wood or plastic tabletop for this repair. It will surely burn wood (not charcoal but will darken) and it will definitely melt or disfigure plastic as we are talking a high amount of hot air !!!
Thats it!
On to other topics, I definitely think a bullet was dodged but, it was the prof who dodged it actually, not me, as he would have ended up buying a new one
The retail price of the new unit where I am is 2500 Euro incl. TAX. So, that repair quote is beyond silly but, what they do apparently is that they don't fix problems as such as these, they just replace all the electronics boards that you see on the picture from my last post. So, its not technically repair, more like changing of parts is what they seem to quote for.
Hope this helps. Thanks!
