HFS-3 Controller Blowing Fuse - Fixed
 

Fixed this before Richard could get back to me, but I'm posting this incase anyone else has this issue in the future.

Upon installing my HFS-3, it blows the 5A wire protection fuse every time I went through the Power Up Procedure as outlined in the manual. Tested all of the wiring and there were no shorts.

I probed the HFS-3 controller board to try and locate the fault: There was a dead short between 12V+ and "power" ground. This short cleared if you remove the onboard fuse.

Tracing the board with a meeter, I discovered the only things connected to "power" ground are the FAV and Pump control mosfets, board power relay, and a diode with the marking "S1J". This cross references to a Vishay rectifier diode with a 1A continuous 40A burst current rating, and it appears to protect the rest of the board from a reverse polarity and power relay coil flyback.

https://i.imgur.com/53fwk2c.jpg

This diode was the only thing that was across both 12V+ and “power” ground, so I unsoldered it to see if that was the issue.

https://i.imgur.com/bqJVX6O.jpg

No more short! The only DO-214AC diode Could get on short notice was a Farchild ES1G, one tier down in specs but probably close enough.

https://i.imgur.com/USRPxjW.jpg

Plugged it in and followed the Power Up Procedure once again, and everything works!

https://i.imgur.com/wabKmxk.gif

This was LIKLEY caused by polarity being reversed at some point while installing it :o.

Re: HFS-3 Controller Blowing Fuse - Fixed
 

good work!