Megasquirt DIYPNP Rework

Last week Josh asked me to help him update the firmware on his DIYPNP Megasquirt ECU, he also needed a base map loaded. So he posted it from Melbourne to Brisbane and I got it early this week.

Josh purchased the ECU second hand off the forums, was told it was working (and I don't doubt that it was) but the surprises came when I opened up the case for a closer look... This is what I found:

  • at least half of the solder joints throughout the board were beyond terrible
  • about a dozen pins/legs had no solder at all
  • the ends of wires were snapping as I was de-soldering
  • a handful of lengthened wires which weren't heat-shrinked
  • tape had fallen off one of the lengthened wires and fully exposed the connection against the metal case
  • loose solder and component pins on the underside, could have easily causes short circuits
  • component pins bent towards each other, more possibility of short circuits

Even if the ECU was working fine, I wouldn't be surprised it failed very quickly in a car environment (heat and vibrations).

So I fully stripped all the wiring off the board, re-soldered every joint, cleaned/removed all the flux, re-wired the connector board, updated firmware and loaded a base map.

Below are some before and after photos.

The wiring was a huge mess, lengthened wires and a lot of fatigued joints which eventually resulted in snapped connections. In the center of the photo you can see the joint that was exposed because tape fell off.

Was difficult to take a clear photo showing the bad solder joints. Looked like a lot of cold joints and not enough solder was used. Quite a bit of flux too.

The wires that snapped clean...

These next photos were taken after I re-worked the ECU.

Re-soldered and board cleaned up to remove all the flux.

The pins on the Microsquirt Module re-soldered and cleaned up.

New jumper wires installed.

My preference is to have the jumper wires on the component side because it places less strain on the wires, helps reduce any fatigue. It also allows easy view of the connections without removing the entire circuit board.

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