rcfocus

I also encountered the Wi-Fi connection issue with 5.3.0. Now I have to use USB stick to transfer the print.

I have the same issue for years. The Wi-Fi connection is just lost sometimes. The Wi-Fi module of UM3 seems very unstable. I don't know it is a firmware or hardware issue. But it is really troublesome to me, I can't use network to send print or check the printing status. A long time ago, I sent the UM3 to Ultimaker reseller to fix the issue. They said Ultimaker will fix this issue in future firmware release. But it is still not fixed yet.

I encountered this issue, too. It is good that Cura includes eSun PLA+ as default materials. But it is bad that Cura always show "Not supported" for it in recent Cura releases. I believe it is a program mistake..... but the Ultimaker team usually don't admit they made mistakes. So, the best way is to find a workaround by yourself e.g. don't use "+" symbol.

Mm... I can no long find official links. Ultimaker team might think it is unnecessary to adjust axes after testing a lot of UM2/UM3 for years. But I think it is still useful to ensure the axes of my UM3 are perfectly aligned. I ever sent my UM3 to reseller for ER18. After the machine is repaired, I used it for several weeks but feel the prints are not as good as before. Until, someday, I found the 6mm shafts are not well assembled to the 8mm shafts. To repair ER18, reseller has to disassemble the printhead to replace one cable. The two 6mm shafts must be removed from the 4 U-shape slots. After repaired, the 6mm shafts must be pushed into the 4 U-shape slots to fix them. But, the shafts were only pushed to 1 of the 4 U-slots. So, all the shafts will "bend" when the printhead is moved to edge of bed. Yes, we just can NOT fully trust reseller for maintenance. In fact, I don't blame the reseller. It takes a pretty long time to learn all the knowledges for 3DP. Experienced employees might leave company and new (unexperienced) employees will make mistakes.

I might not express it well. We know that when current flows through a wire, it creates voltage drop. Large current creates large drop. The situation is the same in a PCB. The power supply is feed in one end of PCB then flows to each regulator (5V, 3.3V...) then to ICs (e.g. ADC). If you look at the positive rail (+24V --> +5V...) then it seems okay. The 5V regulator should still work even for 6V drop. But if you look at the GND rail (return path) then it might not okay if the current is huge. If the return path of heater is not closed to 24V power supply, e.g. it goes through PCB, then a large return current will "shift" the ground level in the GND rail. You might think all GND plane/wires should have the same voltage level. But in fact it is not true because all conductors have resistance. The GND level (voltage) are different in each location/point of GND plane and ground wires. If the heater is controlled by PWM then the situation gets worse. This is because PWM signal is "pulsed" waveform. The power output to heater will also be pulsed. This create a pulsed noise not only in 24V rail but also in ground rail. This also means you can NOT use multimeter to measure voltage. You have to use an oscilloscope to capture the pulsed noise. This kind of noise will create bulk of problems. For example, the ground level might be different at the locations of ADC and INA826 and it creates measurement error. I don't look into UM2 circuit yet. But it will be better if you can ensure the return path of heater is well planned. Since you bought a used machine, all electric components are aged. Aged components might be weaker to resist noise (from power supply, ground or EMI). You have to check them one by one and step by step. First of all, you have to ensure 24V and all the outputs of regulators (5V, 3.3V) are stable with heater enabled. For this, you have to use an oscilloscope (instead of multimeter) to capture pulsed noise.

The extruder temperature you measured is based on the serial output of Marlin. But the firmware doesn't know that the grounding level is dynamically shifted. So, the firmware (PID or other) will still try to make the temperature reading stable while the actual temperature is drifting. I mean, you can NOT depend on the serial output. You have to use an external device to measure the nozzle temperature.

No idea. But as an engineer, I always check the power supply stability for boards (systems) with unknown issues. So, you should check the 2nd item, +24V, before other items.

The queue is only used when you print over wireless. If you use USB stick to transfer the print file then it won't use the queue. So, you can try to print over USB. For the queue, how about remove Cura connection in S5 and then reestablish connection. PS: I don't have UM S5, but UM3. I guess the mechanism should be the same.

I don't have S5. But did you "preview" the sliced result in Cura?

UM3 design files are open source and you can get them from https://github.com/Ultimaker/Ultimaker3. You will need a CAD tool to open the STEP files. As I know, UM S5 isn't open source yet. But I believe the basic structures are the same. For local support team, I think you have to go through resellers. You can find resellers in your country from https://ultimaker.com/resellers.

It is sure you can replace it by yourself. But it might break warranty. If warranty is not a concern then you can print the part by another 3D printer. (My UM3 refuses to work if printcore#2 is not well installed. No idea about UMS5). As I can see, you also need support material to print this part. That means you need another 3D printer with two extruders. The part's file name is "2116-H.STEP". You can download all UM3 STEP files from https://github.com/Ultimaker. I don't know if UM3 and UMS5 have the same printcore design or not. I guess they are the same. But you had better to make sure this issue before disassembling your machine.

Suppose UMS5 and UM3 have the same printcore structure. From the UM3 step file, we can see the spring in pirntcore 2. It should not come out to be seen. That means it is damaged and you should return it to distributor for service.

What you said "I am seeing 'fat' layer vs thin layers that extend in all directions." This could be caused by a dirty Z lead-screw. When a machine is used for a very long time. The Z lead-screw will be very dirty. Please fully clean the lead-screw and then lubricate it again. But from the picture you posted, the lead-screw seems not dirty. Anyway, just try it and see if any difference. Btw, a used hot-end will be very dirty too. You should either use a new nozzle or clean it up at first. I remember there is an article showing how to clean the nozzle (hot-pull & cold-pull).

Well... You said "all belts are tight, the axes are aligned and bed is leveled".... please ensure the belts are not too tight. Please also ensure the short belts connected to X/Y motors are not too tight, not too feeble. Lubricate all axes: the Z lead-screw, two Z rods, two X rods, two Y rods. According to my experiences, you can also try to calibrate the X/Y pulleys. To move printhead in X direction, the two X belts are rotated at the same time by four pulleys. It is possible that the pulleys loosen over time. To ensure the two X belts are synced, we have to ensure the four pulleys are aligned (don't know how to express this!). For X axis, there are two rods and the two belts. You can loose the two screws on one X rod (rod#1). Please also ensure the the screws of pulleys on the other rod (rod#2) are well screwed. Then, tighten the two screws of the pulleys on rod#1. Now the four pulleys are aligned. For Y axis, the structure is the same. So, do it again for Y axis. Please also check the screws of X/Y motor pulleys. You have to ensure all pulleys are tightened.

Z lead-screw wobble is fine. It won't affect X/Y precision. In fact, it is almost impossible to make a perfect lead-screw. So, additional axis rods must be used. The two big rods (at the left and right sides) parallel to the Z lead-screw is used for this purpose. They ensure the precision of X/Y direction. There must be other problem. Since your UM2+ is pretty new, how about sending it back to distributor for service?