There are several things that can be done to eliminate solder shorts on connectors through a wave solder machine. I have not found that orientation makes a lot of difference. How long do the pins protrude? Reducing the length to <=1.5mm on a 0.1" pitch connector will minimize shorts due to lead length. Longer pins seem to attract shorts. I would suggest that you also look at the set up of the wavesolder machine. I have successfully used the following procedure to troubleshoot in the past. 1.You may need to check that the conveyor rails are level side to side and ramp with an angle specified in the Manufacturers Manual (typically 7 degrees). Adjustment is tricky and you should ensure that the PWBs sufficiently contact the Fluxer (wave and Foam types) and the solder wave. (see manufacturers instructions) 2. In my experience, the most critical wavesolder parameter is the Contact Time in the solder Wave (contact time is the period of time that any one point on the PWB remains in contact with the solder wave). Everything else is set up with respect to this value. The Contact Time can be determined using a Lev-Chek glass plate ($60 from Hexacon Electric). The optimum contact time is a function of the CCA thermal density, the speed of the conveyor and the PWB depth in the solder wave. Contact times vary from 2 to 4.5 seconds depending on the above characteristics. NEVER change the speed of the conveyor without considering the contact time. (changing speed also affects the Top Board temperature from the preheat) 3. Next determine the correct preheat temperature (top board temperature) for the flux that you are using (typically 70-85degrees C for RMA). You can use temperature sensitive labels (Cole & Parmer (708) 647 7600 - p/n 8068-02) attached to various points on the top surface of the PWB to determine what the actual preheat is at the exit of the preheater section. Adjust the ONLY the preheater control to obtain the optimum preheat on the board (Remember adjusting the conveyor changes the Contact Time). (use a scrap board for this as you will have to run several times to obtain the optimum temperature) 4. Finally ensure that the fluxer is operating correctly and the Specific Gravity (RMA fluxes) or Flux activity is within the manufacturers specification. You can use the LEV-CHEK to confirm you have good coverage. You should now be able run some tests and modify one paramter at a time to determine the optimum set up for the boards. You will need to use SPC techniques to fine tune the process. Good luck and if you have any comments/questions feel free to contact me. --------------------------------------- Martin Kennett - [log in to unmask] Design Engineer SED Systems Inc. 18 Innovation Blvd Saskatoon, Saskatchewan, CANADA ph (306) 931 3425, Fax (306) 933 1486