Geeetech

Hello guys,

4 weeks ago i bought my first 2 color printer an a20m on ebay.

Since the fist time i powered on the printer i had the jumping temperatures from hotend and bed.
Both jumps + - 5 degrees.
I started the 3 test prints and the all looks great but the printer took a long time to reach the exact hotend temperature.
So i started to print an own model. it also took a long time before the printer reached the exact hotend temperature.
Aafter asking the ebay seller i started the proposed pid on the printer.
The result was worse. the jumping temperatures stayed.
And when i heated the printer (nozzle and bed) i got a temperature error and i should reset the printer.
For two weaks ago i flashed the marlin 1.1.8 version. the immediate error message disappeared.
But my jumping temperatures and long waiting before reaching the temperatures was still available.
I tested also petg my start temperature is 230. the printer cant reach these temperatur.
After waiting a long time i got an thermal runaway error.

Today i flashed the marlin 2.0 but the result is the same.
I checked each sensor and plug. all seems to be ok.

May i have a defect mainboard?

The next error is that i always have diffent z homing heights. with and without 3d touch.
I tryed to cange my z offsets lot of times.
After testing homing and stepping down z -0,1 i got so different results for my nozzle.
I always have to use baby steps before printing.
Is it also a mainboard problem?

The a20m is my third printer, but the first with so many problems which i cannot solve by myself.
Clogging nozzle and under extrusiun are well known problems which i have also solved at the a20m.

I wrote the geeetech technical support, but i got no answer.

Did anybody knows this problems or has a good connection to the geeetech technical support to ask for me?

Regards Brian

I have had my A20M about 3 weeks now and started noticing similar issues the last few days. Now today the printer won't even start printing because the the E1 temp reading is fluctuating too much. I have tried PID tuning and replaced the thermistor, but nothing helped. Now I notice that both the extruder and bed temp constantly fluctuate up to 5 degrees at room temperature. I will pull the cover off the bottom and check all the connections at the board tomorrow, but something is telling me this might be a bad board. My Anet A8 sitting right next to it is holding rock solid temperature readings.

I have the same problem too. I have tried auto tuning the PID settings, reuploading the firmware, checked the connections and swearing at it. None of the things made a difference.

At the moment I have to preheat the nozzle to 3 degrees above printing temperature, let it "stabilize" there, and then start the print. That works most of the time. But the fact that I have to overshoot the target temperature, really stresses the ptfe tube, when I print abs and petg.

I wonder why Geeetech hasn't responded to this thread. Perhaps something will happen, now that there are three customers with the same problem.

Make that 4.

Marlin 2
New thermistor
PID tune done, still get +/-10C

Hard to get a print started

Le_zOU wrote: Sat Mar 16, 2019 8:46 pm Make that 4.

Marlin 2
New thermistor
PID tune done, still get +/-10C

Hard to get a print started

If it still get the same issue.
You can try to check the heat bar input voltage is 24V or not.
Then try to check the PID saved success or not(You need to use the M500 save it)