How to Socket the EPROM in a DSM ECU

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  1. Make certain you are competent. Removing the EPROM is a lot more difficult than you might think at first. It is not a task to be completed with solder braid and a cheap soldering iron! You can seriously damage your ECU if you do not know what you are doing. If you don't think you can do it yourself, perhaps you have a friend who is an electrical engineer or a programmer and owes you a favor. Anyone who would be competent enough to do it would know what to do after reading this document. It really isn't that tough if you have the right equipment.
  2. Remove the ECU. You can follow the instructions for EPROM checking for the first generation and second generation found elsewhere on this site.
  3. Open up the ECU. There are four screws on the outside of the case. Be absolutely certain that you are using the correct size Phillips screwdriver. For some reason, they put tons of torque on some of the ECUs screws. The wrong size head will lead to stripping the screw heads.
  4. Remove the circuit board. There are an additional four screws holding the circuit board to the bottom of the ECU box. Simply remove these screws and slide out the circuit board.
  5. Remove the conformal coating. You might want to remove the conformal coating around the EPROM on both the top and the bottom of the board. This coating prevents oxidation and protects the surface of the board. It is plastic-like and will make a nasty smell when a soldering iron is applied to it. Acetone should remove it quickly. Don't get any on the EPROM label, as it might come off or lose its number stamping.
  6. Desolder the EPROM. It would be best to use a full soldering station including solder sucker. The job goes quite quickly when you have the right equipment. We recommend at least using a Weller soldering station if you must resort to a hand-pump solder sucker and copper braid. Be certain to remove the solder from the bottom and top of the board before trying to pry the EPROM out - you might lift a copper pad otherwise.
  7. Remove the EPROM. Be very careful on this step! Use a small screwdriver or pocket-knife to gently pry the EPROM out. Do not apply much force. If you encounter any resistance, stop and check for remaining solder holding the pins in. If you are not careful here, you will pop traces!
  8. Cleanup. After removing the EPROM, inspect the board pads with a magnifying glass and use an exacto blade to clean up any solder flash on the pads. You also might want to use copper braid to soak up any residual solder, even if you used a solder sucker previously. Also, clean off the pins of the EPROM you just pried out.
  9. Install socket. We use and highly recommend the high quality Augat gold-plated round-hole sockets (28 pins). We've never experienced any EPROM creep even though the socket has seen about 100 in-out cycles over five years. You could also use a ZIF (zero insertion force) socket if you expect to be changing EPROMs quite often.
  10. You are done! At this point, if you like, you can spray on some conformal coating to cover what you removed. Be careful not to get any on the socket's metal contacts. Put the stock chip back into your new socket, or install your upgrade chip. Screw the board back into the bottom case and then screw the ECU cover on. Plug the ECU back into the car and you are done!

1997 Technomotive
September 13th, 1997