24V to 12V Convertor

[Dino]

Hi,
My Broom 37 Continental has a 24V electrical system but some items are 12V. Instead of tapping off one battery the boat was properly set up with a Waeco Perfect Power DC2020 24V to 12V Convertor. I only recently bought the boat and realised that this convertor is not working. I dismantled the unit and found a 20A fuse blown. This fuse was soldered into the board but was fairly easy to replace. I reconnected the fuse and it blew straightaway.
What's the best way to faultfind this unit? Do I need to disconnect each circuit to see what is blowing this?
Or has anyone had a similar issue with this type of unit. Should I install an inline 20A or 15A fuse before the convertor for faultfinding purposes?

 

[Lon nan Gruagach]

Hi,
My Broom 37 Continental has a 24V electrical system but some items are 12V. Instead of tapping off one battery the boat was properly set up with a Waeco Perfect Power DC2020 24V to 12V Convertor. I only recently bought the boat and realised that this convertor is not working. I dismantled the unit and found a 20A fuse blown. This fuse was soldered into the board but was fairly easy to replace. I reconnected the fuse and it blew straightaway.
What's the best way to faultfind this unit? Do I need to disconnect each circuit to see what is blowing this?
Or has anyone had a similar issue with this type of unit. Should I install an inline 20A or 15A fuse before the convertor for faultfinding purposes?

When fault finding a power supply (converter) always start with no loads connected.
If the fuse blows have a much closer look for:
Bulging capacitors, corrosion and salt traces between pcb tracks, blackened components. (hi res pics posted here might help)
Check output voltage.
Add a small load.