Bed won't heat above 73C solved the PS was set at 220v

[Windshadow]

SOLVEDthe bed will only take a n auto tune command for 60c not the needed 100c and it should heat to 80c in about 10 to 12 min from a room at 23c my room is at 20c as I am cheap and i like things on the cool side..
73 C seems to be the max after an hour of heating
. So what is going on?

Three possibilities
1. the power supply is not putting out it's rated power.... Unlikely I think but possible........ AND WE HAVE A WINNER! the PS was shipped selected for 220 volts not 115 and i never checked it so in part all of this is on me. but a note in the manual to check that the switch is in the right position is I think a good idea
2. The bed itself is defective... Also a low chance....
3. The thermistor I installed is faulty… or it is no longer in its proper position in the hole…. Ah I bet this is it. Have pulled the thermocouple used in my heat treating oven to see exactly what the bed temps are over what the thermistor is reporting

Well the bed temp is being reports very closely the thermocouple says 72.4c when the Reported temp for the bed on the LCD is 73.1c
so 3 is not it

I have since learned from Gene that the autotune is not to be used on the bed as it is too large

but when I tried to use it this is what I got
but after doing the averages at 60c i tried to go to 75 and it timed out the same at 70c trying 65c right now

This is a touch wacky:

• at 60c I got Kp --------- Ki --------------Kd
  ------------------------76.91------------1.60---------- 923.35
  -----------------------130.36------------3.43-----------1239.26
  -----------------------109.20-------------2.89----------1032.79
  average ---------------- 105.49------------- 2.64----------1065.10

those all seem reasonable and so i entered them in the bed slots i then after attempting higher I went to 65c and got what looks to me like bad data

• At 65c--------------------------- Kp-----------------Ki---------------Kd
  ------------------------------1374.36-----------588.21---------- 802.8
  -------------------------------- 124.34-------------3.54---------1093.45
  ------------------------------- 1884.83-----------798.49---------1112.29

since the Ki values for the first and third are so large and the second Kp so small I decided to run 66c without entering the average numbers for 65c into the EEPROM
An it once again timed out
I must be doing something wrong.... it worked very neatly for the Hot end
(this is where Gene told me that the autotune was NFG for the heated bed)

any instructions on this are gratefully received the only way I could print the abs fan shroud was to use my heat gun to get the bed to 80c

before I messed with it the settings were as below i just changed the max from 200 to 255 on advice from Nightwatchman should I put them back to this or to the original 200?

Bed heat manager [0-3] 1
Bed PID drive max 255 (was 200)
Bed PID Drive min 80
Bed PID P-gain 87.86
Bed PID I-gain 3.01
Bed PID D-gain 641.82
Bed PID max value [0-255] 255 (was 200)
I did make the change from 200 to 255

[Jrjones]

What voltage are you getting on the output of the Rambo when the bed is fully?
You can also set the heat manager to dead time control, which I find works better for the bed than PID.
try the following for dead time.
Bed heat manager [0-3] 3 (3 is for dead time control)
Bed PID drive max 255 (was 200)
Bed PID P-gain 31 (this is 31 seconds for the bed's reaction time.)

for more on dead time see this http://www.repetier.com/dead-time-control/

But first check what your output voltage is.

[Windshadow]

What voltage are you getting on the output of the Rambo when the bed is fully?
You can also set the heat manager to dead time control, which I find works better for the bed than PID.
try the following for dead time.
Bed heat manager [0-3] 3 (3 is for dead time control)
Bed PID drive max 255 (was 200)
Bed PID P-gain 31 (this is 31 seconds for the bed's reaction time.)

for more on dead time see this http://www.repetier.com/dead-time-control/

But first check what your output voltage is.

i even got down on my arthritic knees but i could not reach the connectors to check the voltage with out risking a short with the essential tremor i have in my hands (i expect that is why i took ove 30 hours to build my printer when most of the reports i read said about 20 hours)
it looks to me that the only way i could check the bed voltage is to disassemble the bbed and remove the capton tape protecting the tabs on the bottom of the heater.

so i have crossed my fingers and applied your change to the heat manager but after 30min it has only gotten to 65c

[Windshadow]

I guess I will revert the EEPROM settings to what they were originally as I did get it up to 73c with them and if i pre heat with the heat gun to 85 or so (and if I get printing on the bed working again
See this thread http://forum.seemecnc.com/viewtopic.php?f=37&t=9551 ) I will have a chance at printing the layer fan shroud and then going over to PLA until I get the bed fixed...

But i will be happy to try anything else first
Bed heat manager [0-3] 1
Bed PID drive max 255 (was 200)
Bed PID Drive min 80
Bed PID P-gain 87.86
Bed PID I-gain 3.01
Bed PID D-gain 641.82
Bed PID max value [0-255] 255 (was 200)

[Jrjones]

Yes, it's hard to get at the output pins of the Rambo when its installed. You could try pulling it out of its mounting location for easier access to the output pins. You shouldn't short anything that way since it's attached to a melamine base.

What power supply do you have in the printer?
One that looks like this one?
[img]http://img.alibaba.com/img/pb/821/662/2 ... 16_643.jpg[/img]

Or an ATX PSU (computer power supply)?

If you have the first one, make sure that the voltage setting is set to 115V or 230V (115V if you are in North America).
This is described on page 33 of the build manual as well.

To speed up the bed heating time, you can put a towel over the build plate as well to help insulate it before printing.
How long does it take your hot end to reach ~220°C?

[Windshadow]

Yes my kit was shipped at the start of this month so it has the newer PS the hot end gets to 220 in about 10 min I think but I have not timed it I will do so in the morning I don't know if I can get at any side switch with out disassemblyand I do not recall that yellow tag on my kit.

I tried the tea towel but it did not get me above 73.4c
the only way I was able to print the PEEK fan shroud was to get the bed heat up to 80c from about 70 with a heat gun to about 86 the heat started to drop as soon as the print started and when the part was about 4 or five layers from done the part popped loose but the part is usable and installed I reran the auto tune for the hotted and the thing will not now go above 220c
yes to 115 I am on the coast of maine

[img]https://dl.dropboxusercontent.com/u/819 ... 281%29.jpg[/img]

[Jrjones]

If your hot end takes 10 minutes then it sounds like the voltage is too low on the Rambo. My hot end when it was stock without insulation took less than 5 minutes if I recall correctly.

Can you check the voltage on Rambo power connector? That should be easier to access.
You can even disconnect the power connector and then stick your multimeter probes in it first, and then turn on the power. That way you minimize the risk of shorting anything.
And your power wires should be long enough that you can pull the connector out of the case with the one acrylic side panel removed.

Even though your having issues with the heating, that print looks pretty good for a first time!

[Windshadow]

Well it was the 3rd try actually each time I heated the bed a but hotter hoping for it to get it to where it retains enough heat to finish the part

JJ has me attacking the MC air printing problems first then its on to this problem

thanks so much for the help

[Windshadow]

Sigh so I found 9.6 volts at the hot end heater and then checked it at the buss connection on the PS and it was also 9.5 to 9.6 across the board the voltage tag ticket is white on my PS and I never looked at it when assembling the printer I could reach the slider from the the rear access panel and I slid it to 115...


perhaps a RED NOTICE in the build instructions to be sure it is set to the builders home line voltage would be a good idea? they why a kit shipped to the US should have it set to 220 is another question. (

[Jrjones]

Glad you found the problem and that it was a relatively easy fix.

[Windshadow]

one other thing was fixed by the erase and reload of the EEPROM
with this file https://github.com/seemecnc/Repetier-09 ... b16b85.zip
the knob on the LCD display worked ion the opposite direction to what the user manual said it should that is to move the effector down the knob was turned to the right rather than to the left... after the erase and PS set to 115V it now works that way the manual said it should...