I few years ago I had good results with reheating/cooling assembled warped boards. If the board was held (fixtured) in the correct position and heated just long enough so that the core temp is just short of the Tg of the laminate, it worked well. It was equally important to let it cool very sloowwly so that new stresses were not created. You mentioned using weight with poor results. It would seem difficult to evenly distribute weight an assembled board. Also, assuming the weight only contacted parts of the board, the cooling rate would not be equal becuase of the differences in thermal mass. The fixture I used was made from 1/2 bar stock. The board was clamped onto the frame and extra short pieces were added as needed to pull the center area flat. The bar stock kept the board flat and allowed air circulation around both sides. Being assembled, check the high temp rating on the components. Either remove the ones that will melt or run at a lower temp. If your temp. is too low, the stresses within the laminate will not be fully relieved. Norm Dill [log in to unmask] ---------- From: TechNet-request To: TechNet Forum Subject: Don't want to scrap it. Date: Wednesday, March 27, 1996 12:06PM Greetings, Does anyone have a good procedure for removing a warp/twist from a pcb? I am dealing with a .093 thick assembly that is 7 inches by 20 inches. The board currenly has smt components placed and soldered (topside only) but, the through hole components have not yet been mounted/soldered. I have tried heating the board and letting it cool while applying weight, that did not do the job. Any suggestions ? please respond. Thanks, [log in to unmask]