Kingpan go bang, is it worth trying to fix?

[PedalPedal]

A clamp for heat sinking became loose and touched the pad of a resistor. R20 exploded. It looks like it might be a 2.2 ohm, but the board looks swollen and cracked underneath the resistor. Even if I go to the trouble of getting the resistor and replacing it (I never knew how helpful Radio Shack was) is it likely that there is enough additional damage to the board that it wouldn't help? The board appears to be potted to the case.

Schematic? http://www.avdweb.nl/solar-bike/electronics/portable-lightweight-lifepo4-ebike-battery-charger-800g.html

 

[amberwolf]

It looks like it might be a 2.2 ohm,

Based on the image, it's a 5-band resistor coded red brown black silver brown, which is a 1% tolerance of 2.1ohms according to this:

https://www.calculator.net/resistor-calculator.html?bandnum=5&band1=red&band2=brown&band3=black&multiplier=silver&tolerance=brown&temperatureCoefficient=brown&type=c&x=108&y=9

If the last stripe isn't brown, you can use the link above to change to whatever color it is to see what precision percentage it should be.

Depending on what else is in the current path of the short circuit, you could have semiconductor damage, such as to the switching FET(s) or diodes (whcih are probably what are held against the heatsink by the clamp that caused the problem). If you like, you can test those parts at least passively with a multimeter before replacing the resistor, to see if there is at least any obvious failure mode (some failures only present under load).