this post was submitted on 01 Nov 2025
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Can bus computer burnt out (infosec.pub)
submitted 1 week ago by Aussiemandeus@aussie.zone to c/askelectronics@discuss.tchncs.de
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This is what's known as a Master 4 module in a LHM550 Liebherr harbour crane.

Earlier this week it was hit by lightning causing the module to output a combined 8 volts out on the can line 3 circuit.

The rest of the module works fine, all functions work except anything related to can line 3.

Can line 3 output is the 2nd white plug port on the top left of the photo.

I know it's probably a long shot but does anyone have any familiarity with these kinds of things?

I have added a couple more photos in the comments.

I couldn't visually see any sort of obvious fail point.

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[โ€“] neidu3@sh.itjust.works 6 points 1 week ago* (last edited 1 week ago) (1 children)

Do the buses really need to be separate? Because what I'd do in this case is to join two buses into one so that you can live without that one port. CAN bus can be connected in parallell, just be sure to modify/relocate the line terminators so you get the right amount of resistance on the data pair. Should be 60 Ohms, iirc. Measure one of the working lines to be sure.

Lightning strikes are a PITA to fix. I spent so many hours troubleshooting this radio installation on a ship and once one component was fixed, another broken one was discovered. In the end we just replaced the entire thing.

[โ€“] Aussiemandeus@aussie.zone 3 points 1 week ago* (last edited 1 week ago)

Unfortunately they need to be separated due to the logic and control system.

Can line 3 is independent of the rest of the machine to allow recovery when it fails.

If it's linked with the rest ordinarily and something like this happens then it would be dead with no simple way to recover it

You're not wrong about lightning though as a crane technician i see lightning strikes far to often and it's always expensive and time consuming