Additional power supply for heatbed

Did you made a measure at the thermistor connectors ?
If you got 0 Ohm, you have a problem.
Mine give 95 Ohm at 23°

Hi Jean D,

yes I have checked the thermistor and get a reading of 109ohm @ about 22c with a quick decrease if heated.

I would check if the correct thermistor type is set in the firmware.
I believe the MK3 uses a different type.

Thanks for that ichbinsnur, where would I find the info for the Mk3 and the place to change the firmware.

During testing I have discovered that the Heater2 is not outputting any power when I click the bed icon.

Heater1 shows 15.4v when called for on the extruder. Connecting the original bed to Heater1 it gets warm, so the wiring to the bed is ok.

Will the wrong thermistor type in firmware give these results…no power output from Heater2. I hope I haven’t blown the Mosfet.

If the temperature goes over 305 °C or below 5°C marlin disables the hotend/heatbed accordingly.
This is to prevent overheating and fire in case of a wiring fault or defectice thermistor.

Normally, the MK3 uses a 100k thermistor, i believe it’s the epcos type, but i’m not sure there.
But that wouldn’t lead to such enormous differences.

I suggest to unplug the hotend thermistor wiring and measure the resiscance at the plug.
If that shows way below 100KOhm at room temp there is a short.
If it shows way more, there is an open circuit or bad solder joint.

cheers,

Christian

Hi Christian thanks for your reply.

The problem is with the Heater2 header on the controller board. There is no power from it when the heatbed is pressed.

This appeared to happen after I installed Mk3 heatbed and RepRap power expander as described a few posts back.

Everything else on the printer works fine.

No error messages in the log?

There are no errors in the log.

How do I post an image. I can upload screen shot of log.

[quote=“Freff789”]There are no errors in the log.

How do I post an image. I can upload screen shot of log.[/quote]

It’s better to copy/paste the log here. Way easier to read.

To upload an image you have to use dropbox or an image hoster and post a link.

like so, for dropbox :
Note you have to change dropbox…. to [color=#BF0000]dl[/color].dropbox… for the IMG tag to work

[img]https://dl.dropbox.com/s/kwz1s12voze4ohs/Complete%20Assembly.jpg?dl=0[/img]

Is this what you need.

12:41:13.192 : OpenGL renderer:ATI Mobility Radeon HD 4200
12:41:13.192 : Using fast VBOs for rendering is possible
12:41:23.098 : start
12:41:23.098 : echo: External Reset
12:41:23.098 : Marlin 1.0.0
12:41:23.098 : echo: Last Updated: Sep 13 2015 23:35:18 | Author: (Boris Landoni)
12:41:23.098 : Compiled: Sep 13 2015
12:41:23.098 : echo: Free Memory: 4298 PlannerBufferBytes: 1232
12:41:23.098 : echo:Stored settings retrieved
12:41:24.237 : echo:SD card ok
12:41:24.284 : FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:http://www.k8200.com/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:K8200 EXTRUDER_COUNT:1
12:41:24.284 : Begin file list
12:41:24.284 : COMPOS~1.GCO
12:41:24.284 : End file list
12:41:24.284 : echo:Active Extruder: 0
12:41:24.284 : Begin file list
12:41:24.284 : COMPOS~1.GCO
12:41:24.299 : End file list
12:41:24.315 : echo:Active Extruder: 0

Well, in priciple, yes.

What would have been good, is to see what the log shows during print or manually heating the extruder and bed.

Sorry, new to this trouble shooting experience.

This is the log copy/pasted. The process worked fine except the bed never heated.

13:12:11.357 : OpenGL version:2.1.8787
13:12:11.357 : OpenGL extensions:GL_AMD_draw_buffers_blend GL_AMD_performance_monitor GL_ARB_color_buffer_float GL_ARB_copy_buffer GL_ARB_depth_buffer_float GL_ARB_depth_texture GL_ARB_draw_buffers GL_ARB_draw_instanced GL_ARB_fragment_program GL_ARB_fragment_program_shadow GL_ARB_fragment_shader GL_ARB_framebuffer_object GL_ARB_framebuffer_sRGB GL_ARB_half_float_pixel GL_ARB_half_float_vertex GL_ARB_instanced_arrays GL_ARB_map_buffer_range GL_ARB_multisample GL_ARB_multitexture GL_ARB_occlusion_query GL_ARB_pixel_buffer_object GL_ARB_point_parameters GL_ARB_point_sprite GL_ARB_shader_objects GL_ARB_shader_texture_lod GL_ARB_shading_language_100 GL_ARB_shadow GL_ARB_shadow_ambient GL_ARB_texture_border_clamp GL_ARB_texture_buffer_object GL_ARB_texture_compression GL_ARB_texture_compression_rgtc GL_ARB_texture_cube_map GL_ARB_texture_env_add GL_ARB_texture_env_combine GL_ARB_texture_env_crossbar GL_ARB_texture_env_dot3 GL_ARB_texture_float GL_ARB_texture_mirrored_repeat GL_ARB_texture_non_power_of_two GL_ARB_texture_rectangle GL_ARB_texture_rg GL_ARB_texture_snorm GL_ARB_transpose_matrix GL_ARB_vertex_array_object GL_ARB_vertex_buffer_object GL_ARB_vertex_program GL_ARB_vertex_shader GL_ARB_window_pos GL_ATI_draw_buffers GL_ATI_envmap_bumpmap GL_ATI_fragment_shader GL_ATI_meminfo GL_ATI_separate_stencil GL_ATI_texture_compression_3dc GL_ATI_texture_env_combine3 GL_ATI_texture_float GL_ATI_texture_mirror_once GL_EXT_abgr GL_EXT_bgra GL_EXT_bindable_uniform GL_EXT_blend_color GL_EXT_blend_equation_separate GL_EXT_blend_func_separate GL_EXT_blend_minmax GL_EXT_blend_subtract GL_EXT_compiled_vertex_array GL_EXT_copy_buffer GL_EXT_copy_texture GL_EXT_draw_buffers2 GL_EXT_draw_instanced GL_EXT_draw_range_elements GL_EXT_fog_coord GL_EXT_framebuffer_blit GL_EXT_framebuffer_multisample GL_EXT_framebuffer_object GL_EXT_framebuffer_sRGB GL_EXT_gpu_program_parameters GL_EXT_gpu_shader4 GL_EXT_multi_draw_arrays GL_EXT_packed_depth_stencil GL_EXT_packed_float GL_EXT_packed_pixels GL_EXT_pixel_buffer_object GL_EXT_point_parameters GL_EXT_provoking_vertex GL_EXT_rescale_normal GL_EXT_secondary_color GL_EXT_separate_specular_color GL_EXT_shadow_funcs GL_EXT_stencil_wrap GL_EXT_subtexture GL_EXT_texgen_reflection GL_EXT_texture3D GL_EXT_texture_array GL_EXT_texture_buffer_object GL_EXT_texture_compression_latc GL_EXT_texture_compression_rgtc GL_EXT_texture_compression_s3tc GL_EXT_texture_cube_map GL_EXT_texture_edge_clamp GL_EXT_texture_env_add GL_EXT_texture_env_combine GL_EXT_texture_env_dot3 GL_EXT_texture_filter_anisotropic GL_EXT_texture_integer GL_EXT_texture_lod GL_EXT_texture_lod_bias GL_EXT_texture_mirror_clamp GL_EXT_texture_object GL_EXT_texture_rectangle GL_EXT_texture_sRGB GL_EXT_texture_shared_exponent GL_EXT_texture_snorm GL_EXT_texture_swizzle GL_EXT_transform_feedback GL_EXT_vertex_array GL_EXT_vertex_array_bgra GL_IBM_texture_mirrored_repeat GL_KTX_buffer_region GL_NV_blend_square GL_NV_conditional_render GL_NV_copy_depth_to_color GL_NV_primitive_restart GL_NV_texgen_reflection GL_SGIS_generate_mipmap GL_SGIS_texture_edge_clamp GL_SGIS_texture_lod GL_SUN_multi_draw_arrays GL_WIN_swap_hint WGL_EXT_swap_control
13:12:11.357 : OpenGL renderer:ATI Mobility Radeon HD 4200
13:12:11.357 : Using fast VBOs for rendering is possible
13:12:18.782 : Access to the port ‘COM8’ is denied.
13:12:31.713 : Access to the port ‘COM8’ is denied.
13:12:41.052 : Access to the port ‘COM8’ is denied.
13:12:53.585 : start
13:12:53.585 : echo: External Reset
13:12:53.585 : Marlin 1.0.0
13:12:53.585 : echo: Last Updated: Sep 13 2015 23:35:18 | Author: (Boris Landoni)
13:12:53.585 : Compiled: Sep 13 2015
13:12:53.585 : echo: Free Memory: 4298 PlannerBufferBytes: 1232
13:12:53.585 : echo:Stored settings retrieved
13:12:54.677 : echo:SD card ok
13:12:54.708 : FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:http://www.k8200.com/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:K8200 EXTRUDER_COUNT:1
13:12:54.708 : Begin file list
13:12:54.708 : COMPOS~1.GCO
13:12:54.708 : End file list
13:12:54.724 : echo:Active Extruder: 0
13:12:54.724 : Begin file list
13:12:54.724 : COMPOS~1.GCO
13:12:54.724 : End file list
13:12:54.771 : echo:Active Extruder: 0
13:13:36.891 : Starting object analyser …
13:13:36.891 : Object is manifold.
13:13:36.891 : Analysing finished.
13:16:43.826 : CuraEngine command:C:\Program Files\Repetier-Host\plugins\CuraEngine\CuraEngine.exe -p -v -c “C:\Users\Tony\AppData\Local\RepetierHost\cura.ini” -s posx=0 -s posy=0 -o “C:\Users\Tony\AppData\Local\RepetierHost\composition.gcode” “C:\Users\Tony\AppData\Local\RepetierHost\composition0.stl”
13:16:43.951 : Cura_SteamEngine version 14.12
13:16:43.951 : Copyright © 2014 David Braam
13:16:43.951 : This program is free software: you can redistribute it and/or modify
13:16:43.951 : it under the terms of the GNU Affero General Public License as published by
13:16:43.951 : the Free Software Foundation, either version 3 of the License, or
13:16:43.951 : (at your option) any later version.
13:16:43.951 : This program is distributed in the hope that it will be useful,
13:16:43.951 : but WITHOUT ANY WARRANTY; without even the implied warranty of
13:16:43.951 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13:16:43.951 : GNU Affero General Public License for more details.
13:16:43.951 : You should have received a copy of the GNU Affero General Public License
13:16:43.951 : along with this program. If not, see http://www.gnu.org/licenses/.
13:16:43.951 : Default config ‘default.cfg’ not used
13:16:43.951 : Loading C:\Users\Tony\AppData\Local\RepetierHost\composition0.stl from disk…
13:16:43.966 : Loaded from disk in 0.015s
13:16:43.966 : Analyzing and optimizing model…
13:16:43.966 : Face counts: 32 -> 32 100.0%
13:16:43.966 : Vertex counts: 96 -> 16 16.7%
13:16:43.966 : Size: 70.000000 55.101000 25.000000
13:16:43.966 : vMin: 65.000000 72.449000 0.000000
13:16:43.966 : vMax: 135.000000 127.550000 25.000000
13:16:43.966 : vMin: 65.000000 72.449000 0.000000
13:16:43.966 : vMax: 135.000000 127.550000 25.000000
13:16:43.966 : Matrix: 1.000000 0.000000 0.000000
13:16:43.966 : Matrix: 0.000000 1.000000 0.000000
13:16:43.966 : Matrix: 0.000000 0.000000 1.000000
13:16:43.966 : Optimize model 0.000s
13:16:43.966 : Slicing model…
13:16:43.966 : Layer count: 125
13:16:43.966 : Sliced model in 0.000s
13:16:43.966 : Generating support map…
13:16:43.966 : Generating layer parts…
13:16:43.966 : Generated layer parts in 0.000s
13:16:43.982 : Generated inset in 0.016s
13:16:44.013 : Generated up/down skin in 0.031s
13:16:44.824 : Wrote layers in 0.81s.
13:16:44.824 : Wrote 792.3 kilobytes.
13:16:44.824 : Total time elapsed 0.87s.
13:16:44.824 : Print time: 2883
13:16:44.824 : Filament: 1614
13:16:44.824 : Filament2: 0
13:17:29.362 : Printing layer 1 of 125

Does the log really end at : 13:17:29.362 : Printing layer 1 of 125 ?
Or did you terminate the print there?

[quote=“Freff789”]Hi Jean D,

yes I have checked the thermistor and get a reading of 109ohm @ about 22c with a quick decrease if heated.[/quote]

Opps!
Do you really mean 109 Ohm?
Should be around 100[color=#BF0000]k[/color]Ohm (100000 Ohm)

It should be 109[color=#FF0000]k[/color]ohm, my bad.

Ah, ok then.

Does the led light up when the heatbed should be on?
If not, try Restore factory settings in Repetier’s Firmware EEprom config.
Maybe your EEprom is messed up.

No red light I’m afraid.

Done a factory reset and that had no effect.

With these symptoms, do you think it could be the Mosfet that’s above the Heater2 header.

If the LED doesn’t light up the Mosfet doesn’t switch.
Can you check if the voltage on the gate of the mosfet (on 18 on the Atmega chip or at R10) changes between 0v and 5v when the bed turns on and off?
Just to find out if the microcontroller tries to switch the heatbed.

You want me to put one multimeter probe on the mosfet gate and the other probe on pin 18 of the mega chip. I can barely see the chip let alone the pins. Will I do any damage if the probe touches another pin accidentally. I have old eyes.

Where will I find R10. Sorry to be so vague.

To check if it works put the positive probe on the gate pin of the Mosfet and the negative to ground.
If you now switch the heatbed on and off, there sould be a change between 0V and 5V at the gate pin.

If that is true, probably the Mosfet is dead. (receck by measuring the same on the working extruder heater)

If not, it can be a circuit fault, damaged Microcontroller or a software (firmware) issue.