1 Topic by lcjnsb

  • lcjnsb
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Topic: Axiom Direct Dual Rambo replacement

Im working with an Airwolf 3d Axiom Direct Dual printer and the heated bed stopped working. I opened the back and the 15 amp fuse was blown. I checked on Ultimachines site and found that the fuse is for the heated bed.  I replaced the fuse and it blew as soon as the printer was turned on, so I replaced the fuse and pulled the connector for the bed and turned on the machine, it blew again. Looking at the bed connector, it has been hot, so I figured the bed was drawing too much current. The resistance on the bed is 2.6 ohms. That would mean the bed is pulling a little more the 200 watts and pulling 9 amps which shouldn't blow a 15 amp fuse. Now I assume there must be a short on the board. maybe it fried some of the pcb. BTW everything else works on the printer, if you don't count the lousy prints.
I told my boss and he ordered a new Rambo from Ultimachine.
I guess my question is: does airwolf do anything special to the board that would stop me from replacing it with an of the shelf Rambo? I do have the hex files for the machine.

Larry

2 Reply by carl_m1968

  • carl_m1968
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Re: Axiom Direct Dual Rambo replacement

I would measure the resistance between each bed heater lead and common ground on the power supply or the case. To blow that fuse you would need a near direct short to ground. The fuse protects the source of power from the downstream items that use the power. In this case the board is the source and heater is the user. So the issue is between the bed and fuse, not the board.

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.

3 Reply by lcjnsb

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Re: Axiom Direct Dual Rambo replacement

Thanks Carl
But as I explained in the original post, it still blows the fuse with the heated bed disconnected. That just leaves the board as the problem. I have tested the bed for for a short and it is not shorted. That leaves just the board as the problem, with the charring on the board cable conncetor I am assuming it go to hot and caused a short on the board,  I have not removed the board yet, but is the only logical conclusion.

4 Reply by carl_m1968

  • carl_m1968
  • carl_m1968
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Re: Axiom Direct Dual Rambo replacement

If you look at the schematic for that board the 15 amps fuse feeds what is called 12V2 which is the second 12 volt rail in the system. Just a brief look shows that HEAT0 and HEAT1 (extruders), bed heater, FAN0 and FAN1, as well as what ever might be connected to the auxiliary power power port V++2 out are all fed by that fuse so any of these could cause a short and blow that fuse. Any of the drivers for these devices such as the FETS for the fans or the heaters could do it. If you know how to measure parts with a meter you could figure out what part is actually bad. otherwise you will need to replace the board. Unless it is a board specifically designed for your machine you will also have to flash the firmware to your version as well once replaced.

http://soliforum.com/i/?6mul1WK.png

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.