Several of us dudes have been looking into some failed chargers to determine if repairs are possible. In the bad units we have seen that the input start relay and by-pass resistors have been overheated and failed. The main board has been traced and sketched up in another thread: http://www.diyelectriccar.com/forums/showthread.php/tcch-elcon-1-5kw-charger-schematics-89470.html
We have made some good progress on tracing up the control board, and in the process found a defective FET driver that was pulling down the 12vdc supply. This may be the mechanism for causing the relay and bypass resistors to get so hot.
The fet driver was drawing excess current from the 12vdc supply (the viper circuit) such that the viper went into re-start mode. But doing that would cause the start relay to lose hold-current and go open--now the full 120vac would be carried thru the 2 paralleled 150 ohm bypass resistors (~190 watts in 1 watt devices).
We hooked up an oscilloscope and applied power to the viper and found it was in an infinite start-up loop and never able to kick in to regulation mode due to the Fet driver load. When we isolated the driver out of the load path, the viper came up and went into normal regulation. It appears to be a good device but should be swapped out anyway since it may have been overstressed.
The control board has two separate 12vdc supplies generated by the viper--one for the analog section and one for the digital portion of the control board. The analog end shares power with the start relay and the digital end shares power with the output relay.
If anything should cause the analog-end 12vdc supply on the control board to get pulled down low, it will take out the start relay and cause catastrophic failure of the charger due to the by-pass resistor configuration.