It is still printing, but I can’t seem to understand this language… Don’t know what happened, it’s all scrambled on the LCD but the program is still running
Try sum |0x38, that’s for the ASCII table
@Keveen_Rodriguez Hi this never happened before , its the first time, maybe it will go away after restart, but any ideas why ? is it power supply or dc to dc converter bad quality and it scrambled some of the ram ?
bad power connections or something on that power line has a back coupling happens to mine too when i switch on my soldering station on the same power line but print finishes just fine - have to get a better station - or maybe the psu of the printer isnt well isolated
@Googolplex_Goku Thanks ! that make sense
Shielded tape might help. My printer did that all the time until I wrapped the two display cables with shielded tape. Works fine now.
Or it’s the power supply mentioned above.
Let it finish printing. Will be fine after a reboot.
Yep, usually caused by electrical noise getting into the LCD wiring.
Check if there is a pattern between characters on display and what should be written. If so one (or more) of the screen data cables got loose and ASCII chars are loosing one bit.
I rebooted it after finishing the print. It’s fine now. I think that was Inductive load of one of two fans that I am using on the same line or led strip . I will try to not turn on off anything during prints. Thanks !
you guys think a filtered power inlet would prevent this ?? salvaged this double fused baby out of some lab equipment 
or ill just give it a try
@Googolplex_Goku Maybe let us know, but from what I have experienced on one of my arduino robots with servos powered from the same source - probably proper isolator chip would be required and they are expensive alternative is dc to dc converter like http://gaia-converter.com/ but I never used one, too expensive, I always had to make my way around
@Piotr_Sitko If you are shure that the problem is power supply that is unstable; Investing in expensive power sources would be the brute solution.
IMO this is what you need: a cheap AC-DC supply, delivering you 12 or 24V (whatever you need for your heavy lift: steppers, heaters, fans…) then below that a stable dc-dc converter that gives you 5, 3.3 or 1.8v for your crucial logics (from the 12 or 24v). Logics usually drain just few Watts so you can get a decent step-down or linear converter (if wasting energy is not a concern) for 5-10$. The second supply will detach your logics from main noise. If that is not enought then go smarter:
- Reduce length of logic-power cables.
- Do not twist logic and heavy power lines.
- Shield high speed data wires.
- DECOUPLING CAPACITORS: put some extra capacitors to logic power supply and then some smaller (maybe ceramic) next to each high speed LOGIC (arduino, serial receivers, transmitters, LCD).
- Add electrolitic capacitors ON each motor driver.
- Add some small (100-1k ohm) resistors on digital lanes that cross the power areas. Example: the lane connecting arduino to motor drivers (that MUST be powered by dthe main supply).
- In the most extreme cases shield logics.
IS IMPORTANT to note that each wire IS A RESISTOR and so it behave. Greater is the current flowing greater is the voltage dropdown. Therefore never ever power power electronics and logics with the same wire. Even if ‘logically’ it is the same connection, once you take in account high frequenci or high current noise you will se that it changes from working to not.
If you wish to share your schematics I will be glade help.
If your mains power is putting noise into the LCD screen, your PSU sucks. Buy a higher quality PSU and it will filter that stuff out and deliver clean DC. But even if your PSU sucks, the regulator circuit providing 5v or 3v3 to your LCD will provide an additional layer of filtering. I think it’s unlikely to be an issue with your mains power.
I think it’s much more likely that your motor or heater wiring is radiating EM noise into your LCD ribbon cable. This is a common problem. Stepper wiring in particular is insanely noisy and can throw spurious signals into endstop wiring, LCD wiring, etc. Physically separate stepper wiring from all other wiring. I also recommend twisting the stepper wiring (for each coil pair of wires) but that’s a fair amount of work.
@Ryan_Carlyle I thing you got the point. But don’t you agree that current irradiation noise are the main problem only when you have high power steppers? Personally I’ve never encountred such issues in a 3d printer where accellerations and momentum are small. I allways found out that noise wasn’t induced current but rather great woltage spikes on PSU’s capacitors caused by stepper coils getting activated with cheap single level MOSFET drivers and without a tuned LC compensation.
@Borut_Svara I’m pretty sure it’s the PWM chopping in the drivers. Poor gate switching timing creates big spikes. The Allegro 4988 is really bad about this and is used in tons of printers. I don’t think the motor motion matters much, but who knows.
Werd
yy i know a better psu will solve the prob i just bought a cheap printer because i didnt knew if 3d printing is something for me but yeah its definetly for me - but it would still be nice to know if a filtered inlet would fix the prob - as a quick/cheaper fix - i also got some tracopower psus one has 24v/6.5 amps and one 12v unknown amps cause i have to pull it out of some equipment the others i dont know - havent looked over them yet - i will write back the next days when i got time to install the filtered inlet
@Ryan_Carlyle yes I used A4988 in cheap project quite a lot. With nema23 steppers i solved as follow: 220uF capacitor on power input (for each driver) then tuned ceramic one for each stepper winding. It allmost removed noise