Need Help!

We have recently completed the build of our Huxley at University.

This is a 2013 model with the Melzi board and has been working fine.

It the middle of a PLA build today the wires to the heated bed came loose and stupidly to finish the print we soldered the wires while the power was on and when everything went off and we think a short has occurred.

After reconnecting the 19v power cable we could not get the system to Home.

The Pc can connect to the Huxley –Initially we get the message shown in the screen shot attached. (Message)

If we press the reset button on the board we get the second message. (message2)

The system does not move to the home position when requested.

We have checked the inputs and are getting 19v at the board and power inputs, 19v across the heated bed pins and 5V across the power jumper on the Melzi.

The board LED is flashing, when home is selected the board LED goers out and the system freezes with no messages. The system then needs to be switched off and then on again.

Is there anything else we should try? We were wondering whether this is a case for reinstalling the firmware but this seemed a bit daunting.

Please could you advise if there is another possible fix?

Soldering irons are generally grounded, so in soldering the connections with the board live, you shorted the heated bed connections to ground.

Try moving the drives individually using e.g. G91 followed by G1 X1, then G1 Y1, then G1 Z1. Monitor the 19V supply while you do this. My guess is that at least one of the stepper motor driver chips has failed, so that activating that motor is causing a short across the 19V supply, causing it to shut down.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

thanks for getting back. we tried that and nothing happens. The fan comes on and there is power across heated bed pins and everything is on but when we command it to move to the home position nothing happens,

Have you tried to disconnect all motors and give the commands with no load?
The behavior is the same if you home any axis?
Are other power commands working? I mean heating the bed or heating the hotend or turning fan on.

when I plug it in the fan comes on automatically. but the other commands dont work either! I cant set the temp both the bed and the hot end.

And the behaviour is same when I home any axis!

All hell broke loose when I soldered the 19V power wire that connects to the bed while the power was on! I think it short circuited and everything went off. So after soldering and wiring it back on the fan comes on as soon as i connect the plug and it connects as my first picture shows. but when I press the home icon it doesn't respond. Hope this information helps

Check with the power jumper taken out. This will power the logic from USB and eventually eliminate some influences of the commands to the 5V rail. However, I think you fried something, unfortunately.
Which wires did you actually solder (+19V, GND, thermistor or command wire) and which other wires do you think could be touched (shortcircuited) during the "repair"?

it was the 19v wire that is connected to the bed. I Just kept the tip of the soldering iron on the 19v wire that is connected to the bed. The wires that were connected to bed came loose and fell out. And once I did keep the tip on the wire everything went off. I really dont know what to do now. but once I finished my soldering I screwed the wires in and everything comes on, Including the fan. I can see the normal room temperatures of the bed and hot end but when i click 'set temperature' nothing happens. Do u think it could be a firmware issue.

I think for some reasons, perhaps some higher voltage appeared on the tip of the soldering iron (it is not uncommon) has find the way from the +19V rail to the microcontroller outputs that control the drivers and fried them. Now, whenever after a reset (which configures the outputs as inactive) you give a command, the 5V rail drops and the controller enters in an undefined state. You can check the voltage on +5V when you give a home command. Obviously, I might be wrong.
If bed and/or extruder heating does not block the controller (and I understood they just do not work), check the voltage on the gate of the MOSFET that is driving the bed or extruder. It should go near +5V. For the bed, disconnect the connector for the driver and thermistor and apply +19V for a while. If the MOSFET is alive, the bed should start heating.
I recommended you to take out the 5V jumper to allow powering the controller from USB. Maybe it works like this. Though I doubt, it might be interesting to observe the behavior in such configuration.
And do not despair. Have a look here: [www.aliexpress.com]