Extruder Not Working, Prusa I3 Aluminium

[Stunzasr20]

Context: I have Prusa I3A (Sanguinololu board) , setup with Repitier Host. I live in Australia so 220V is the mains voltage and I have ensured that the PSU switch is set to 220V. I have checked voltage output at the PSU between both the V+ and both COM terminals, when the printer is at "idle", and i have read 11.8V in all 4 cases. I would also like to note i have not printed anything at this point (brand new setup) and am still solving the setup. I only appear to reach 90 Degrees (aim is 200 Deg C) for the extruder. I also would like to note that the MK2a heatbed only is reaching 45/90 degrees. So in other words both are only appearing (according to the LCD screen) to aproximately half the target temperatures.
So i am just wondering if anyone can offer suggestions on what might be causing such a problem. I only mention the heatbed as maybe this tells you more about the whole picture but the immediate issue is that I can not extrude any material, even manually in Repitier Host.
Hopefully that gives context of the problem but if any more information is required i will provide it as necessary
Regards
Shaun

[Mark]

how's the PSU output after you heat up the heatbed and hotend? is it still 12V?
And the PSU, you can turn the trimpot on it to adjust the output to about 12V, see if it works, but note that as you said, you need to make sure you have set it to 220V.

[Stunzasr20]

I ran repetier host in manual control and turned on both extruder and heat bed and it maintained voltage, ( I adjusted as you suggested and brought it up to 12.0V , by which on heating it was very stable over a period of 10mins.
However in this space of time the extruder only reached max 90deg (mostly it arrived to that temp in 2-3mins). The heat bed warmed up but nothing changed after it hit 45deg just stayed on that temp.
How long should it take for the extruder to heat up to 200deg?
Any other suggestions would be greatly appreciated, thanks

[Mark]

usually it will be in 5mins to reach 200 degrees.
how's the resistance of the heaters and heatbed? you can check this link :
http://www.geeetech.com/forum/viewtopic ... 19&t=17039

[Stunzasr20]

Ok thanks, 5mins seems reasonable.
The heater (extruder) was tested same method as your referred link showed 3.5ohm , which agreed with your reading.

The heating wires on the heat bed (large red wires soldered to heat bed ) showed 1.8 ohm.

Upon turning on the printer (at idle) the LCD shows 25/0 47/0. This appears as the heat bed thermistor is bad as room temp is 25deg.
Switching the connections of both thermistors at the control board produces 0/0 47/0.


Are you able to confirm the resistance at the thermistor of the heat bed ? I got 1.3K ohm

[Mark]

the resistance for the thermistor is 100k, BUT it will change according to the temperature, you can check the voltage between the pins of thermistor connector, it should be 5V.

[Stunzasr20]

I checked the voltage at idle (just switching the printer on without trying to do anything or plug laptop in) and i get 4.7V

If i then plug the laptop in and turn only the headbed on the voltage begins to drop as the heatbed temperatire increases (by touch i can tell the heatbed is heating up).
I allowed and watched it for 5 minutes and the voltage contrinued to drop and after it reached 3.44V on my meter I decided to turn it off.
The weird thing about it is, the temperature on the LCD remains 45/90, but in repetier host the temperature increases (but under the extruder section) not the heatbed section, ie the the heatbed section in repitier remains as per the screen, So not sure what it happening with that, because i never turned the extruder on. The extruder (the hot end) remained cool to touch and was most certainly not on.
Any ideas what could be causing all these issues?
Greatly appreciate any advice

[Mark]

if like you said the wirings are all correct, the have you checked the firmware, have you tried to reinstall it?

[Stunzasr20]

I did about 2 months ago, I will try again if you suggest this could help