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No Power to the resistors that heat the hot end.

Posted: Wed Dec 23, 2015 8:28 pm
by cameron98199
Hi - I'm currently troubleshooting a problem with my printer.
Printer is a Rostock Max V1, running the latest repetier software.

In repetier manual mode, I can't get the extruder to heat up (I click the extruder icon, but get no temperature increase.)
Power cycling the printer and rebotting software had no effect.

Using a multimeter, I get zero voltage across the extruder power pins on the RAMBO board while I command the software to heat the extruder.
15 AMP fuse is OK.

Current activity: I'm looking at the extruder wiring to see if there's short somewhere that could have blown something on the board. Trying to determine what could be damaged on the board to make the extruders not work, but everything else work fine.

Questions:
1. I see a 15 AMP fuse on the RAMBO board- does the extruder use this fuse or is there another?
2. What is the resistance on each of the resistors in the extruder?
3. If there is a damaged component on the board, can anyone speculate what that component may be and how to test it?

Strategy:
1. Fix any shorts in the extruder wiring.
2. Remove and replace any bad components on the board.
3. Restore function to extruder, without having to buy a new RAMBO board.
4. Resume printing.

Thanks, Any help appreciated!

Re: No Power to the resistors that heat the hot end.

Posted: Wed Dec 23, 2015 8:41 pm
by mhackney
See http://reprap.org/wiki/Rambo

The hot end fuse is the little 5A fuse at F3. Does your fan work? It's on the same fuse.
These little guys are easy to blow. I'm guessing that's your problem.

The resistors in the hot end are 6.8 ohm

Re: No Power to the resistors that heat the hot end.

Posted: Wed Dec 23, 2015 9:36 pm
by teoman
Does it heat up when you set the temperature from the LCD of the printer?