No Power to Rambo [Solved]

[noname117]

Printer: Rostock Max V2 with He280

I'm think I have a diagnosis for this one but I'm hoping I'm wrong

So I was a few hours into printing a long t-glass print teps set to 240 and 75 when the printer stopped and screen turned off. The only thing that's was still running was the psu fan. I pulled it apart and tested it with a multimeter and get 12v on the connector going into the Rambo, 0 ohms across all the fuses on the board and no lights on anything. I'm guessing it's a dead board.

Is there a more thorough way check this for sure and if I am right about the dead board, anybody got a suggestion on why it failed?

Solution: Testing the fuses in the board caused them to all test fine despite one of them being blown. Thanks to Mac the Knife for pointing this out.

[geneb]

I would carefully check the power input terminal block and make sure it's tight and not discolored. Were you printing via SD card or USB?

g.

[noname117]

I would carefully check the power input terminal block and make sure it's tight and not discolored. Were you printing via SD card or USB?

g.

Double checked it. 12v across all the screw heads. Also printing via sd

[Mac The Knife]

You did remove the fuses from the board when you checked them?

[geneb]

Good point - if you check the fuses in-circuit, you can get a false "good" indication.

g.

[noname117]

You did remove the fuses from the board when you checked them?

Nope. This was the problem. the top tiny fuse mounted directly left of the power input to the board was blown but read fine when tested in the board. Thanks for the tip. Now I have to figure out why it blew. Could a short in one of the layer fans have blown it?

[noname117]

Good point - if you check the fuses in-circuit, you can get a false "good" indication.

g.

Yep. Learned something new today. Testing the fuse in the board made it look fine. Could a short in the layer fan have blown the fuse?

[geneb]

It's certainly possible.

g.