UM2 Extrusion Upgrade killed main PCB motor drivers!?

[lon 1]

I just installed the Extrusion Upgrade kit on my Ultimaker 2. Process went pretty smoothly... except after reassembly none of the motors would spin! First error I got was ER06 Z-Stop switch stuck. But the switch is fine, the problem was that the Z motor was not running. Playing with Pronterface I verified the bed heater still worked, but all three stepper motors did not move.

And also... the A4988 stepper drivers are all very hot on the PCB! Even when motors are not supposed to be running.

I conjecture that I burned out the drivers by manually sliding the print head and bed. This spins the motors pretty fast since they are geared up. I measured >50Vpp coming out of the motor while sliding print head! That might be enough to burn out the gates in the driver chips.

Anybody else see this happen?

[gr5 2,181]

The motors won't move because of the stop switch. There's lots of possiblities. The most likely is that something fell in the hole where the stop switch is - lift your Z bed with 2 hands and look under it - there is a screw sticking very far down. Look where that screw will go - jiggle that stop switch - make sure you hear it click. Often a piece of plastic gets in there. If nothing obvious yet, take the cover off the PCB again and trace that cable - I'm thinking you disconnected it maybe during the upgrade.

[lon 1]

Nope - it was the A4988 motor driver chips on the main board. The stop switches were fine. I replaced the main board ($349!) and everything works again.

Anybody want to take a look at my old board?

[Legolindsay 0]

Nope - it was the A4988 motor driver chips on the main board.  The stop switches were fine.  I replaced the main board ($349!) and everything works again.

Anybody want to take a look at my old board?

 

Faaark! Exactly the same thing here, only it only one motor dead.

After installing the Kit, I get er05 or er06 depending on the location of the build platform. The switch is working and has continuity right through to the main board.

The instructions should tell you to disconnect the stepper motors before moving the platform and head.

This is terrible! I think Ultimaker should accept responsibility for the omission.

Bugger.

[Legolindsay 0]

 

Nope - it was the A4988 motor driver chips on the main board.  The stop switches were fine.  I replaced the main board ($349!) and everything works again.

Anybody want to take a look at my old board?

 

Faaark! Exactly the same thing here, only it only one motor dead.

After installing the Kit, I get er05 or er06 depending on the location of the build platform. The switch is working and has continuity right through to the main board.

The instructions should tell you to disconnect the stepper motors before moving the platform and head.

This is terrible! I think Ultimaker should accept responsibility for the omission.

Bugger.

 

When simply moving the stage, I measured 16 volts peak to peak across the motor!

Theres a video here:

Looks like the the A4988 ic has no protection for voltage coming back from the motor.

I'd say there is a very real risk of blowing up the motor driver ic's when moving the motors.

Lindsay Robertson

Senior Technician (EAS) (NZCE)

Departmental Health and Safety Officer

Department of Psychology, University of Otago

Te Tari Whakamātau Hinekaro, Te Whare Wānanga o Otāgo

Godard Laboratories, Level 2, 95a Union Plc East

PO Box 56, Dunedin 9054, NEW ZEALAND

Tel 64 3 479 7668 Fax 64 3 479 8335

Website: www.otago.ac.nz/psychology

[neotko 1,417]

I have zero knowhow about electronics but on my 3 umo+ (same board) I have moved z/x/y while plugged/unplugged and never had a stepper damaged.

It's true that the power comes back to the board se nce if you plug a led strip to the 19/24v 2 pins you can actually see the led going on/off when moving the bed/x/y by hand (with or without the power supply connected).

Worse case scenario, you could build a marlin firmware for your printer changing the pins.h so the damaged stepper works on the extruder2 stepper. It's a very easy and fast mod.

[JoeDini 0]

Hi..i am new user here. As per my knowledge the motors won't move because of the stop switch. There's lots of possiblities. The most likely is that something fell in the hole where the stop switch is - lift your Z bed with 2 hands and look under it - there is a screw sticking very far down. Look where that screw will go - jiggle that stop switch - make sure you hear it click. Often a piece of plastic gets in there. If nothing obvious yet, take the cover off the PCB again and trace that cable.

High Density Interconnection PCBs

Edited July 15, 2016 by Guest

[Legolindsay 0]

Hi..i am new user here. As per my knowledge the motors won't move because of the stop switch. There's lots of possiblities. The most likely is that something fell in the hole where the stop switch is - lift your Z bed with 2 hands and look under it - there is a screw sticking very far down. Look where that screw will go - jiggle that stop switch - make sure you hear it click. Often a piece of plastic gets in there. If nothing obvious yet, take the cover off the PCB again and trace that cable.

 

Thats a really bad idea.

As I said already, I've measured the switch opening and closing from the mainboard. The microswitch is fine.

In fact, Its the act of moving the stage up and down manually that causes the back voltage that blows up the driver IC.

If you're going to manipulate the stage, make sure you unplug the motor first!!!

[gr5 2,181]

I move the Z stage and the heads all the time with power off and with power on. Never a problem. UMO, UM2, UM2+, UM2ext, UM2go. In fact if power is off on UMO and you push the head around the controller board lights up. Scare - but not a problem. I have done this thousands of times and on over 50 different Ultimakers.