Teardown Siemens Versicharge VG2 30A

We received this Siemens Versicharge VG2 because it would charge and the front panel lights were not correct. The timer "2" was on and pressing the time change button displayed an error.  On further testing there was very erratic light action and you could here the power relay closing. 
Normally this type of problem is caused by the DC power supply so we opened the case and check the power supply. The +5V, +15V & -15V power supplies were OK.   We installed our spare control board and and the problem was not fixed. We installed our spare power and control boards and the problem was not fixed. The problem had to be in the chassis.  We disconnected the orange Pilot wire and tried again,  It worked.  So the problem was in the cable or the J1771 handle. To be sure we left the Pilot wire disconnected and stimulated the charger with our tester.  We used a hammer and a chisel to open the J1772 handle (Destructive)  We found that a small circuit board for the Prox switch took power from the Pilot signal. We cut that orange wire connection and the Versicharge worked normally.  There was obvious corrosion and on the Prox circuit board.  We installed a use J1772 cable and handle and it all worked.   
Moral,  We went on a wild goose chase re the power supply,  Always check the cable and handle first. Note:  Most J1772 handle do not have Prox circuit board and would not have this problem.  Note; The client then told us about water damage to the J1772 handle.
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