Repairs – Change the Hotbed Thermistor – I3 Mega S

This machine has long been problematic so when this came up I used it as an opportunity to show you guys how to change the thermistor of my hot bed.

Transcript

Hello everybody and welcome to another repair video. In today’s video I’ll be showing you how I was able to replace the thermistor on my 3D printer and finally fix the ongoing issues with my printer. Now a quick disclaimer that this video wasn’t sponsored by Anycubic and to do this modification at your own risk.

So before anyone asks, I’ve been having issues with this machine for a very long time. Unlike my first I3 Mega, this one has been prone to stopping randomly, and although I’ve replaced quite a few components and updated the firmware the issues have persisted. While most of the issues were from prints failing to complete on this occasion things were quite different. The print bed temperatures were fluctuating quite dramatically which was preventing the print from starting. I had replaced the motherboard in the past, updated the firmware, replaced the SD card reader and re-checked the wiring, so I was fairly certain that these weren’t the issues. So I unscrewed the build plate and began double-checking the resistance with a multimeter.

The very first thing I noticed was that the thermistor was completely black which could be normal however I still decided to double-check. So the resistance rating for most of these thermistors is normally 100k, but I was reading some strange numbers. Also, you’ll want to make sure that the print bed is fully cooled down prior to trying to take your measurements since this seems to affect the readouts. I also noticed that the readings weren’t the same once re-soldered together so that’ll be something you want to keep in mind.

While soldering, I noticed that the old solder wasn’t coming off easily even when adding flux. I suspected that the heat bed was helping to defuse the heat, so I preheated the surface, but that wasn’t enough. I ended up adding some fresh solder to the connections along with flux which then allowed me to use solder wick to remove the material from the connection points. Once I removed the old thermistor I noticed that there was a small hole where the thermistor was located. With the black coating it’s difficult to see so here’s a small diagram to show you what it looked like.

I did need to shape the wires slightly to make sure that they would align correctly however everything soldered together nicely. After testing it the resistance seemed better than before, but I wasn’t entirely sure that it had worked since i wasn’t getting the same results as when I tested the thermistor prior to soldering it into place. I decided to put the machine back together and do a final test.

When everything was put back together I began running the test print. I had outfitted this machine with a 0.8 nozzle since it was originally used for printing large functional parts. The first print didn’t look good in the beginning however the temperatures quickly stabilized and stopped fluctuating irregularly after the first print. All following prints had stable temperatures. This also got me thinking about what might be the issue with this machine. When I began hitting the reset bottom for the machine all issues stopped when starting a new print. So I began to experiment with the G-code a bit and after trying out the G999 command and a couple of others I decided to compare it with another machines settings. This is where it discovered that there was some extra lines of code and decided to copy and past the end G-code from my CR10-V3 to see if this made a difference. Sure enough, after over a year of being problematic the problem finally seems to be fixed. Or was it? Unfortunately once I started a larger print, I began running into the same issues as before although at least my print bed temperatures were correct this time. I will be posting the G-code in the description below just in case it does end up working for you.

Having seen a lot of issues with the wiring hubs of this machine I will begin trying to rewire it in an effort to get the machine working properly. Make sure to keep an eye out for the follow-up video when I undergo this process since I will be including a price breakdown as well.

So was this repair worth it? I’d say yes considering that the thermistors are fairly inexpensive now days especially the one’s which are compatible with the Anycubic printer. In case some of you were wondering, I bought the NTC 3950 100k version at the time from Amazon however if you’re worried about compatibility issues and don’t want to risk having to change your firmware settings you may which to order it from the main Anycubic website. After over a year of having a problematic machine, I finally seem to have one that works on par with my expectations.

CR10 V3 Fix – Cable Connection Supports

Video tutorial on to install replacement cables for the CR10 V3

Download Files

Instructions

In today’s article, we’ll be addressing the issue with the cable for the hot end assembly of the CR10 V3. If any of you may have noticed, the cable connections don’t have any support and there’s a high probability that the movement will cause a failure in the connection. The cables which connect to the hub are also another potential issue since they don’t have any support either. Since I would like this machine to last as long as possible, I will be making a couple of modifications to address these issues today. As always, do these modifications at your own risk, and I’m in no way responsible for any damages which may occur.

So, like most modifications, this one went through a couple of alliterations before a final version was determined. Since the metal supports for the xz hub were the same design as the V2 model, I decided to use this to my advantage. I initially designed a mount which surrounded the cabling, however this proved both difficult to mount and risky to force the cable within the support. It was for this reason that I switched to an open design, which allowed me to use Zip ties to fasten the cables to the guide. For the hot end assembly, I knew I wanted something which simply slipped over the direct extruder motor. After taking precise measurements, I created a box like shape to encompass the motor while still keeping as much of it open to prevent overheating issues. I also designed it to wrap around the connector, so I would be able to add zip ties as well. Learning from my previous mistake, I made sure to keep an open design.

After my first test, I did discover one drawback which I hadn’t initially taken into account. While testing just how high up I could move the printer in the Z axis, I found out that my modification did remove some of it’s Z height. Wanting to reduce this drawback as much as possible, I then redesigned both the parts to help resolve this. With the new design, I was able to comfortably reach a total Z height of 395. I also made sure to better support the cables with an extra Bowden tube that I had lying around, however you may be able to use a spiral cable wrap instead should you have some available. Very important to note is the fact that you’ll have to move the support bar on the left-hand side of the machine to accommodate the increased size of the nozzle assembly. To do this, you’ll want to completely remove the top portions and bottom portions. For the bottom, you’ll want to add some washers to increase the distance at the base. You’ll then want to move the nozzle assembly as far up as you can, while also moving as far left as possible. This will make it easier to gage where to place the new connection points. In my case, I had to realign the live bolt and move the pull rod connector over so that only one support bolt was still in place. Instead of using the spacer which came for the live bolt, I removed this and replaced it with a M5x12 screw. As long as this is properly tightened, you should have no problems getting this secured in place. Make sure to write the Z height that you have, since you’ll change the maximum Z height for your machine in your slicing program.

With this completed, it was now time to change the Z height in Cura and begin a test print. As expected, the test prints were very similar to those done previously. Since I had a 0.8 nozzle, these were the results that I ended up getting. Since I mostly use the larger machines for functional parts or prototypes, I often need these to complete at a faster rate.0.2

Although I could leave this machine without these additions, this will hopefully help increase its longevity. If you want to see how I upgraded the hot end to use an all metal one, you can see the full tutorial article at this link HERE.

Important Notes

Print all the parts beforehand
Do a test fit first
Write down your new maximum Z height
Zip ties are needed
one M5x12 Screw
Adjust Pull Rod connector + Live Bolt

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CR10 V3 Fix – Filament Sensor Mod

Video tutorial on how to Upgrade the Filament sensor for the CR10 V3.

Download Files

Instructions

In today’s article, we’ll be covering how to go about modifying the filament run out sensor that came with the CR10V3 so that it stops catching. As always, please do this mod at your own risk, and I’m not responsible if any damages may occur.

So as I mentioned in my previous review of the Creality CR10 V3, the sensor was very much holding back the potential for this machine. Because of the initial design for the filament intake, it caused a severe amount of friction to occur, which in some instances prevented the proper flow of filament through the nozzle. Before trying to create a new housing, I did run a test to see if I could simply replace the existing sensor with one that I had lying around, however this produced an error which prevented the printing process from starting. Instead of modifying the firmware, I decided to change the housing, which I believed to be the main cause of the issue. The electronics themselves were very well-designed, so doing this also makes this modification easier for other’s to undertake.

So the very first step was to remove the existing component and open it up to see what was inside. Luckily, this was fairly easy to accomplish because of how it was assembled on the machine. Once you remove the 4 screws holding it in place, you are immediately greeted with the electronic components. To make my life easier, I did decide to remove the filament stand, however this is not a necessary step.

Once the electronics were visible, I removed the two screws holding them in place so that I could get a better look at the housing that already existed on the machine. The first step was the remodel of the area where the sensor would be sitting, and once that portion as completed, I was then able to focus on the entryway for the filament. The issue with the stock version is that the angles were too sharp, and this was what was causing the large amount of friction. Also, the alignment was slightly off and this caused the filament to get stuck in the switch portion of the mechanism. In order to address these issues, I created a gradual entryway for the filament to the pass through and changed the point where the filament intersected with the switch. This produced a much more gradual entrance, which reduced the friction significantly.

With this out of the way, it was now time to create the connection points in which the two halves of the sensor would meet and combine to make the shell. I then added the bolt indents to further make this easier to assemble. So after a couple of prototypes, I finally had the final version that I would be installing on my machine.

IF you decide to install this one in your own machine, you’ll need to do the following. You’ll need to add the two screws to hold the switch in place, after which you’ll add the screws and bolts for the housing. In my case, I only had longer screws available, so I ended up only installing two of these across from each other. This also allowed me to place a much longer screw going in the opposite direction to attach this to the sensor mount. I added a bolt behind it just to make sure that it didn’t come off later on. With that completed, I installed it onto the machine and quickly tested it with both flexible and PLA filament. After doing my first print, I can say that it’s still working quite well, and I’m happy with the results. This was the resulting test cube, which was printed with a 0.8 nozzle and scaled to 130%.

Although this may seem like a simple mod, I found this to be one in which I appreciate the most since the friction being produced has caused my filament to break in mid-print on certain occasions. In the next article, we’ll upgrade the hot end to use an all metal hot end one for higher temperature printing.

Checklist

Download + Print Files
Remove original sensor
Careful take out electronics
Place into new housing
Assemble

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