I have spent all lunch hours and a couple of evenings stripping the board. At this point I now have all the tall pieces off and it’s now ready for the next max resolution scan.
Turbowsr, it’s good to see that you took the time to find the high strap resistor pads, I hope you get an opportunity to find the pins (or maybe I should say test points) for the two missing blue signals. I shall continue to concentrate my efforts on the stripping and scanning of the MB. (my TFT has not arrived yet either) I shall also try to post my progress a little more frequently.Figure out some way to make this available to everyone.
Lessons Learned, Observations, & Theories
Surface mount canister capacitors: Those itty bitty solder points on opposing sides of the capacitor actually extend about 1/3 or the way under the capacitor from each direction. One solder iron can easily liquefy the solder on one pin, but even the slightest tilt of the canister will cause the opposing side to tear up the trace. To remove the capacitors without tearing up a trace requires melting both solder points at the same time. I had to track down a second soldering iron to remove the capacitors.
Removing multi pin through hole components with a paint stripper heat gun; Making such an attempting in an office environment is frowned on. Doing it on the loading dock solves the office environment concerns but any little breeze significantly reduces the component removal rate. I was averaging about 20 minutes per part and certain pieces such as the parallel connector and the processor socket I simply was not able to remove in such an environment. It would take a lot of lunch hours to remove even just the tall components at that rate. Constructing some sort of wind break is a must. Having a significant portion of the engineering department huddling around trying to figure out what you are doing is a close second.
The up side of using an 11 AMP B&D paint stripper in this manner was that it doesn’t burn the board even when left in extremely close proximity for an extended period of time. In one case I actually let it “sit” “On the Board” for about 15 minutes with one edge propped up about an 1/8 inch (so the air could flow) without burning the board. OK, maybe this particular paint stripper is a little marginal to be doing this in a breeze, but it did work.
Post Removal: As slow as the paint stripper was at removing through hole components I decided to try another approach for the posts. The approach that worked well was to use one of those butane micro torches (cigarette lighter on steroids) that Rat Shack dumped for 99 cents about a year ago (it was in the Deals Deals Deals thread, I hope you got one) and a piece of a pop can with a hole poked through it for a heat shield. I put the flame tip directly on the post from the back side of the board, and as long as I did not slide the heat shield off center it did not burn the board. The posts came out very quickly.
NOTE: The application of the torch without a heat shield caused the surrounding board area to burn almost instantly (this was determined in a practice test conducted on a separate board, “before” using this method on the i-o). Also, when applying the torch flame through a hole in a flattened pop can the heat causes the aluminum to curl, at that time you must be very careful to hold the edges of the hole down, because, if one edge lifts, the flame will burn the board under the edge almost instantly (this was determined on the i-o #$&^%&). Fortunately, the back side of the board had already been photoed.
Suggestion: To use a pop can as a heat shield, use the bottom of it. Put the hole through the center of the bottom and trim the side of the can down to the point that the edge of the hole and the edge of the can both sit on the board. Because of the shape of the can bottom it resists curling and is a lot easier to work with.
BTW: The inside for the micro torch is actually a refillable cigarette lighter (looks very similar to a Bic) but the nozzle in the micro torch controls and concentrates the flame a lot better than a cigarette lighter by itself could ever do.
Removing Components In Your Oven This was definitely the most productive source of last weeks “lessons learned”, “observations” and “theories”. But I’ll have to write about it later.