http://ebikes.ca Learn tab then Troubleshooting has information on how to test FETs and other stuff, but you will need an ohmmeter. Even a super cheap DMM like the ones they sometimes give away at Harbor Freight and places like that will do the job. You may not have any place like that around you, but the internet abounds with them.
In my experience when one cap has blown, the others are probably damaged as well (the same is often true of FETs) when they are all on the same power bus exposed to the same severe overvoltage event. So probably all of those large caps will need to be replaced, even though only one has actually vented.
If you did not have the "keyswitch / doorlock / ignition / etc " wire connected to battery positive when the event occured, then the low-voltage (non-fet) stuff may still be perfectly ok.
If you did have it connected, then almost certainly at least the input stage is damaged, and potentially everything down the line depending on how the components failed (shorted, open, etc) and how quickly events progressed.
In my experience when one cap has blown, the others are probably damaged as well (the same is often true of FETs) when they are all on the same power bus exposed to the same severe overvoltage event. So probably all of those large caps will need to be replaced, even though only one has actually vented.
If you did not have the "keyswitch / doorlock / ignition / etc " wire connected to battery positive when the event occured, then the low-voltage (non-fet) stuff may still be perfectly ok.
If you did have it connected, then almost certainly at least the input stage is damaged, and potentially everything down the line depending on how the components failed (shorted, open, etc) and how quickly events progressed.