[thingstodo]

Moving on to the inspection of the Open ReVolt controller, a DIY build. It was built by someone but not completed and tested. That person sold the not-quite-finished project to me.

Being paranoid, I removed it from the case to examine it and perform any tests that I could before taking the leap of faith and turning on the power.

The control board is assembled neatly (ReVolt_Top1). Component leads are trimmed. Resistors are bent consistently, and the resistors are close to the PCBoard. The design does not *REALLY* allow for the dis-assembly of the system after all the components have been soldered in place. You need to remove the solder from one side of 10 resistors to separate the control board from the power board. The edge of the control board can be lifted to allow some pictures to be taken, so I did that. 4 bolts, nuts and standoffs were removed to allow the control board to be lifted on one side (ReVolt_Under).

After the pictures were taken (no obvious issues on the bottom of the control board), the control board was put back in place and secured (ReVolt_Top2).

Further examination of the top of the control board identified three locations where the solder did not wick up to the top of the board from the bottom (where the solder was fed). Good solder joints have a pool of solder within the circular hole that holds the leads, and the pool extends up to the top of the board (or nearly).

That got me thinking about Cold Solder Joints. So I methodically checked each of the visible resistor solder joints from the top of the control board. I noticed that there are a few resistors where the solder is too visible on the component side, like the resistors were soldered from the component side instead of the other side. The solder should not look too much like a sphere. A small tug on the end of each of those 3 resistors results in 1 resistor coming completely out of the PCB hole (ReVolt_Cold_Solder). A textbook case of a Cold Solder Joint. I'd guess that this resistor is not the only one on the board.

So I will be removing the 10 soldered-in resistors that hold the power board to the control board so that I can check and resolder the control board, then check and resolder the power board, as required. While I'm at it, I should be verifying polarity for each part against the PCBoard artwork. And with my GREAT memory ... I'll be using a picture of an unpopulated PC Board, verifying each solder joint and each component polarity, and marking the good ones in green and the bad ones in red. That way I can re-check the ones that I re-soldered when everything is done and not have to re-check solder joints that were not changed.

Oh well ... at least I checked before powering it up!

This Open Source controller is no longer what you'd call Low Hanging Fruit. The repair and checking of this controller is not difficult but will take a while, and since there is already a workable solution in the Kelly controller, my time is better spent on other tasks.

I will put away Paul and Sabrina's ReVolt 500 Amp Open Source Controller until it becomes the highest value task.