Help! did I just fry my motherboard?

[nirfriedman]

Finally have time to start looking into this. All fuses verified, and I rechecked that there are no short circuits in the extruder.

Connecting the printer to S3D I get two errors.

One is "SD init fail" which is ok since I had to remove the RAMBO cover with the SD-reader.

The second is that a reply to "T0" command is "CRC mismatch detected". AFAIK CRC means parity check, but it does not see that there is a communication error.

Additionally note that the temperature on Tool 0 starts to rise although the target temp is 0.

RECEIVED: echo:Marlin 1.0.0
RECEIVED: echo: Last Updated: Sep 10 2015 19:53:35 | Author: (none, default config)
RECEIVED: Compiled: Sep 10 2015
RECEIVED: echo: Free Memory: 4141 PlannerBufferBytes: 1232
RECEIVED: echo:Hardcoded Default Settings Loaded
RECEIVED: echo:Steps per unit:
RECEIVED: echo: M92 X88.88 Y88.88 Z400.00 E471.50
RECEIVED: echo:Maximum feedrates (mm/s):
RECEIVED: echo: M203 X500.00 Y500.00 Z25.00 E25.00
RECEIVED: echo:Maximum Acceleration (mm/s2):
RECEIVED: echo: M201 X4000 Y4000 Z100 E10000
RECEIVED: echo:Acceleration: S=acceleration, T=retract acceleration
RECEIVED: echo: M204 S2000.00 T3000.00
RECEIVED: echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
RECEIVED: echo: M205 S0.00 T0.00 B20000 X8.00 Z0.40 E5.00
RECEIVED: echo:Home offset (mm):
RECEIVED: echo: M206 X0.00 Y0.00 Z0.00
RECEIVED: echo:PID settings:
RECEIVED: echo: M301 P25.89 I1.94 D86.53
Testing plaintext communication protocol...
Testing binary communication protocol...
RECEIVED: echo:SD init fail
RECEIVED: ok
Connected to machine!
SENT: T0
WARNING: CRC mismatch detected
RECEIVED:
SENT: M105
RECEIVED: ok T:64.0 /0.0 B:23.1 /0.0 T0:64.0 /0.0 T1:23.2 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:68.5 /0.0 B:23.1 /0.0 T0:68.5 /0.0 T1:23.1 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:73.4 /0.0 B:23.1 /0.0 T0:73.4 /0.0 T1:23.1 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:78.1 /0.0 B:23.1 /0.0 T0:78.1 /0.0 T1:23.1 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:82.6 /0.0 B:23.1 /0.0 T0:82.6 /0.0 T1:23.1 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:87.0 /0.0 B:23.1 /0.0 T0:87.0 /0.0 T1:23.2 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:91.7 /0.0 B:23.1 /0.0 T0:91.7 /0.0 T1:23.2 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:96.0 /0.0 B:23.1 /0.0 T0:96.0 /0.0 T1:23.1 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:100.3 /0.0 B:23.1 /0.0 T0:100.3 /0.0 T1:23.2 /0.0 @:0 B@:0
SENT: M105
RECEIVED: ok T:104.4 /0.0 B:23.1 /0.0 T0:104.4 /0.0 T1:23.2 /0.0 @:0 B@:0
Disconnected.

[nirfriedman]

Turns out CRC mismatch is a S3D warning, and was not repeated.

I reloaded Marlin (after compiling out the SD card just to avoid that error). Still the same problem ---Tool 0 heater is constantly on even though the software thinks it is off.

[ednisley]

Tool 0 heater is constantly on even though the software thinks it is off.

Alas, a shorted MOSFET behaves that way: always on.

While it's possible to replace the transistor, the least-bad alternative will be just buying a new controller.

[Tim]

Alas, a shorted MOSFET behaves that way: always on.

Yes, I think that's the likely conclusion. So after much trial and error, the answer to your original question "did I just fry my motherboard" appears to be "yes". Like Ed suggests, I think you fried a single power MOSFET. The RAMBo has exactly 5 power MOSFETs, which covers the bed heater, two extruder heaters, and two fans, so there's nothing left over to act as a spare unless you want to try to rewire the extruder and case fans directly to the power supply. The power MOSFETs are surface-mount devices with a large pad connection underneath acting as a heat sink, so they are very hard to impossible to get off with a soldering iron without damaging something, and using a heat gun is tricky with all the plastic parts nearby. I once tried to replace the motor controller chips but gave up. So a new controller card is probably the only realistic option left.

[nirfriedman]

Alas, a shorted MOSFET behaves that way: always on.

Yes, I think that's the likely conclusion. So after much trial and error, the answer to your original question "did I just fry my motherboard" appears to be "yes". Like Ed suggests, I think you fried a single power MOSFET. The RAMBo has exactly 5 power MOSFETs, which covers the bed heater, two extruder heaters, and two fans, so there's nothing left over to act as a spare unless you want to try to rewire the extruder and case fans directly to the power supply. The power MOSFETs are surface-mount devices with a large pad connection underneath acting as a heat sink, so they are very hard to impossible to get off with a soldering iron without damaging something, and using a heat gun is tricky with all the plastic parts nearby. I once tried to replace the motor controller chips but gave up. So a new controller card is probably the only realistic option left.

Ouch. Thanks guys.

The next inevitable question, any special things to know about controller replacement, just buy a RAMBO 1.2 board?

[nirfriedman]

Can I configure the machine to use a single extruder (Tool 1)? So I can do some work until I get a new board

[jsc]

Just don't plug anything into Tool 0 and set up the slicer to use Tool 1.

[nirfriedman]

Just don't plug anything into Tool 0 and set up the slicer to use Tool 1.

Marlin detected nothing connected to Tool 0 and stops the printer.

I am trying to find how to configure Marlin to a single extruder (easy) and to use Tool 1 as though it is Tool 0 (should be easy but didn't work)

[jsc]

Okay, try this.

In Configuration.h, set EXTRUDERS to 1.
In pins.h, set HEATER_0_PIN and TEMP_0_PIN to the values for HEATER_1_PIN and TEMP_1_PIN, in the RAMBO section.

[nirfriedman]

Okay, try this.

In Configuration.h, set EXTRUDERS to 1.
In pins.h, set HEATER_0_PIN and TEMP_0_PIN to the values for HEATER_1_PIN and TEMP_1_PIN, in the RAMBO section.

Thanks! I discovered I also need to set the extruder pins (or rewire the extruder engine).