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Hello, today I had a problem during printing.
While my Rostock Max suddenly worked the thermistor of heatedbed scored a temperature of -20 °.
I thought it was broken but actually connecting the thermistor to hotend I verified that this worked correctly.
In Repeterier Host is not reported no errors, but I no longer turn on the extruder and even the bed.
I tried to change the small fuses (both engines of the thermistor) and I checked the fuse for the heatedbed work properly. What may have happened since the thermistore of heatedbed work correctly with Rambo but I can not get it to work?
Repeterier Host has put in DRY USER MODE therefore I can not do anything.
Looks great help

thanks

modellazione3d wrote:Hello, today I had a problem during printing.
While my Rostock Max suddenly worked the thermistor of heatedbed scored a temperature of -20 °.
I thought it was broken but actually connecting the thermistor to hotend I verified that this worked correctly.
In Repeterier Host is not reported no errors, but I no longer turn on the extruder and even the bed.
I tried to change the small fuses (both engines of the thermistor) and I checked the fuse for the heatedbed work properly. What may have happened since the thermistore of heatedbed work correctly with Rambo but I can not get it to work?
Repeterier Host has put in DRY USER MODE therefore I can not do anything.
Looks great help

thanks

Check the resistance of the thermistor when at room temperature with an ohm-meter, should read approximately 100K if that checks okay check for wiring problems
from the thermistor.

Eaglezsoar Thanks for the quick response.
I gave a controlled thermistor marking 127k (I think it's more or less ok) and I've verified that the connections were open and functioning.
  I thought about changing the port of the thermistor of the bed with the extruder (which I left off) and repetier read the temperature of the bed, but in the window of the extruder!
How can I change this setting to set a different port to the heated bed? I'm a noob

modellazione3d wrote:Eaglezsoar Thanks for the quick response.
I gave a controlled thermistor marking 127k (I think it's more or less ok) and I've verified that the connections were open and functioning.
  I thought about changing the port of the thermistor of the bed with the extruder (which I left off) and repetier read the temperature of the bed, but in the window of the extruder!
How can I change this setting to set a different port to the heated bed? I'm a noob

Are you sure that you did not plug the wire from the heated bed thermistor into T0 and the wire from the hotend thermistor into T2 on the Rambo?
The hotend thermistor is supposed to plug into T0
The heated bed thermistor is supposed to plug into T2

Yes, the thermistor of extruder is connected at T0 and it works.
The thermistor of the bed is connected to T2 and does not work.
I tried to connect the thermistor of the bed in the slot T0 and Repetier verified that the bed and the thermistor function, but not on port T2.

modellazione3d wrote:Yes, the thermistor of extruder is connected at T0 and it works.
The thermistor of the bed is connected to T2 and does not work.
I tried to connect the thermistor of the bed in the slot T0 and Repetier verified that the bed and the thermistor function, but not on port T2.

Your T2 port somehow got destroyed and is no longer functioning. Do you know how to edit the firmware, recompile and upload to the Rambo?

You are going to have to remap pins in your pins.h file and I don't want you doing this unless you are confident you know how to edit the file,
recompile the firmware and upload it back to the Rambo. Let me know your level of expertise and if you are not comfortable doing this then we need to
know that. Basically we are going to remap pin 2 to pin 7 inside of pins.h The finished pins.h will look like:
#define HEATER_BED_PIN 3
//#define TEMP_BED_PIN 2
// I popped the thermistor input on my RAMBo so I'm using the 4th thermistor connector on the board.
#define TEMP_BED_PIN 7

Recompile, upload and all is well again. You would plug your thermistor for the heated bed into T3 on the Rambo. DO NOT DO THIS IF YOU ARE NOT SURE!

Also another experienced user verify my pin assignments and verify they are correct before modellazione3d uses them.

Thanks Eaglezsoar I followed the steps and now everything is back ok. I connected the thermistor pin T3 in bed and I modified the firmware as you said. Now I can read through Repetier temperatures regularly
I hope to resume printing quickly;)

PS: why the T2 pin is burned? I fear that happening to other pins? And if it happens, what should I do?

modellazione3d wrote:Thanks Eaglezsoar I followed the steps and now everything is back ok. I connected the thermistor pin T3 in bed and I modified the firmware as you said. Now I can read through Repetier temperatures regularly
I hope to resume printing quickly;)

PS: why the T2 pin is burned? I fear that happening to other pins? And if it happens, what should I do?

I'm glad the the pin changes worked and you were able to use a different thermistor port. Good job in doing the pin remapping.

The version 1.1 series of the Rambo board are sensitive to static spikes and other potential sources of voltage on the thermistor ports and a capacitor
on the ports opens and the port stops working. Ultimachine is aware of the problem and the design of the new 1.2 series of boards have built in circuitry
that helps to stop that from happening. Those of us who own the older revisions have to remap the pins and use a different port which is what you had to do.
If you run out of ports you would have to send in the Rambo board for repair, fix it yourself if you have the knowledge or buy a new board. That's just the way
it is and Ultimachine did come out with the new version which shows they are pro-active in fixing these kind of problems when they come find them. What bothers
me is that I asked another user to look at my pin remappings and let us know if they looked correct and not one person on this forum responded. We are here
to help one another and it seems at times users forget that.
Anyway, we got you up and running again so I'll close with my favorite ending - Happy Printing!