Wanhao Duplicator I3 Plus: Ribbon Cable Pinout

This is the pinout information for rebuilding a Wanhao Duplicator I3 Plus using a RAMPS control board. My printer is actually a Monoprice Maker Select Plus, but it is manufactured by Wanhao. Therefore, I have decided to start referring to this printer as a Wanhao machine in hopes that others who have various rebranded printers will be able to get the help they need.

Communication from the control board underneath the printer to the small daughter board behind the actual print head is done through a 16-pin ribbon cable. I had to figure out which of the sensors and actuators in the daughter (or breakout) board corresponded with the ribbon cable pins.

This is the best way I could figure out how to explain it that made sense to me. If you discover that any of this information is incorrect, I would greatly appreciate you letting me know. As I write this, I am still in the process of the rebuild. I have not been able to test everything in actual practice. Only through what my continuity tester tells me.

Ribbon Cable PinoutGraphical layout of ribbon cable.

Above is a drawing of the output of the cable underneath the print bed. You need to patch into this cable and connect the various pins to the RAMPS control module.

Here is what I have figured out each of these pins do.

  • Pins 1-4: Heater Ground
  • Pins 5-8: Heater Voltage, Hotend Fan Voltage, PWM Fan Voltage
  • Pins 9, 11, 13, 15: Extruder Motor
  • Pin 10: PWM Fan Ground
  • Pin 12: Thermistor Voltage
  • Pin 14: X-axis Limit Switch
  • Pin 16: Hotend Fan Ground

I am using DuPont cables to plug into the ribbon cable and then out to the RAMPS module. Once I get it all working I plan to superglue blocks of cables together (all the grounds for example) so that when you pull one you pull all in that block. Also I will replace the 4 individual cables that connect the extruder motor with a 4 pin block of DuPont connectors. This will keep me from accidentally switching around the wiring.

Then, when I have all the wiring worked out properly, I will hot glue everything together with the ribbon cable connector. This will ensure nothing comes loose unexpectedly, but I will be able to remove wires if necessary.

Modify RAMPS for 24 Volts

One of the first things you need to do to complete a Wanhao Duplicator I3 Plus (or Monoprice Maker Select Plus) conversion to work with RAMPS is modify RAMPS to work with a 24 volt power supply. The other option is to pull out the 24V supply and put in 12V. But that would require changing some of your other hardware and you also lose any advantage that the 24V supply gives in the first place. For me, I chose to keep the (theoretically) better 24V supply and modify RAMPS.

If you have not already bought your RAMPS board, please read through this whole post before purchasing. After reading you can make a better choice and save a little work by buying the right one.

Also, don’t power up the RAMPS board until you have completed all the steps in this post. In a later post I will show you how to wire everything up. It is probably best to wait until you get to that point before applying power.

Choosing a RAMPS Board

You should assume that your RAMPS board is designed to work with 12V. They do make boards that can accept both 12 and 24 volts, and you might want to buy one, but it is best to assume your board is 12V and confirm that it will work with 24 before plugging in the higher voltage to test.

The cost of a 12 volt board with stepper drivers and LCD screen is the same as a 12-24V RAMPS board by itself. All the 12-24V boards that I found had the Arduino Mega integrated into the same board as the Pololu shield. I personally like discrete components (as much as is practical) so that if one part dies it can be replaced without having to replace the whole system.

Therefore, my preference was to buy a $40 kit that included the Arduino, Pololu shield, stepper drivers and LCD that needed to be modified for 24V. As opposed to $40 just for the Arduino/Pololu integrated system without drivers and LCD but was already setup for 24V. You will have to decide that on your own. If you buy the 24V setup, then you can completely skip this step. But you will have to figure out the LCD and stepper drivers on your own.

For the rest of this step, I assume you have a 12V RAMPS board. You can get them at the supplier of your choice: Amazon, eBay, dx.com, AliExpress or Gearbest. There are many other places to get them, but that should get you started. I chose Amazon for this because I wanted it quickly and for RAMPS, stepper drivers and LCD in one package buying from the Chinese shippers and waiting up to 2 months was not much cheaper (if at all).

Capacitors, Fuses and Diode

Assuming you have a 12V RAMPS board, there are three types of components to check or modify to make it work with the higher voltage supply: capacitors, fuses and diode.

Image of the RAMPS control board.

In the image above (you can click it to get a larger image), you will see various components highlighted with circles and arrows. Refer to this image for the parts below.

Capacitors

There are two different sets of large, electrolytic capacitors. They are physically different sizes which should make it easier for you to identify the different ones. In the image above the capacitors circled in yellow are the ones you need to be concerned about. The 3 circled in green should not need to be checked or modified in any way for working with 24 volts.

The 6 yellow-circled capacitors should be rated at 48V or higher. Your’s may say something like 36V, 100V or some other cryptic code for the voltage rating. A lower rating than 48V does not mean that the board is unusable. However, if they are less than 36V you really should replace those capacitors. And you can expect it to not work at all, or very unreliably until it fails, if your capacitors are 24V or less.

I am not an electrical engineer, but what I have read is that you will want to have capacitors that are rated for at least double your working voltage. In our case the working voltage is 24V, therefore these capacitors should be rated for at 48V. Currently, mine are 36V and I am going to take the risk and run with them like this. They should be fine, but we have been warned.

The reason we don’t have to worry about the green-circled capacitors and their lower rating is because they are not using the 12 or 24 volts from our power supply. That segment of the board is stepped down to 5 volts. Therefore, whatever the manufacturer originally installed for that section of the board should be sufficient.

Diode

The diode (pointed at by the pink arrow) is the path through which electricity goes into the Arduino and powers it. Since most Arduinos are rated for up to 12V of power, we don’t want to feed 24V into it. Therefore, if we get rid of this diode then we stop the 24V from going through the Pololu shield and into the Arduino. That means that after this step is complete we need to find a way to power the Arduino separately with 12V.

Removing the Diode

You can remove the pink-arrow-highlighted diode by snipping the wires on either side of it or by desoldering it. It would be very hard to get a pair of wire cutters in the space to snip the wires on the diode, but it is possible. I chose to desolder mine. You can watch a video or read an Instructable about desoldering components if you don’t know how.

My board had another diode next to the poly fuses. You should leave this one in place. Only disable the one indicated by the pink arrow.

Supplying 12V to the Arduino

Now you have to power the Arduino in some way. The way I chose to do it, and the way I recommend, is to use a step down power converter. Also called a DC-DC or buck converter. What this does is take the 24V from the main power supply and converts it (steps it down) to 12V that can be used for the Arduino (and cool looking 12V LEDs). I had already installed one of these in my printer for the purpose of powering LEDs. So this was an easy route for me.

Just because something is easy, doesn’t mean it is best. However, in this case, I think this is the best way to go about powering your Arduino. The other option is to have an external 12V source for the Arduino. It can be a battery (which could leave you with a dead Arduino in the middle of a print) or it could be a second supply plugged into the wall (which is an extra external component). In either case, you need to tie the ground of the battery or secondary supply to the ground of the 24V supply. Too much work.

Use a Step-Down / DC-DC / Buck Converter

A small buck converter will take the 24 volts from our current supply and easily convert it to usable 12 volts. That is what it is designed to do.

My converter (shown above) can take up to 32 volts as input. Then there is a screw adjustment to dial in the output voltage.

Tie Into the Power Supply

I soldered wires from the IN+ and IN- side of the buck converter and ran those to the extra screw terminals on the power supply. Wasn’t it nice of them to leave an open spot for us to use? Make sure the IN+ goes to the 24V+ terminal and the IN- goes to the 24V- of the power supply. The following picture shows where I tied in my buck converter. The first and fourth screw terminals (from the left) on my power supply were empty. These were the ones I used.

Turn the adjustment screw (actually a multi-turn potentiometer) on the buck converter until your volt meter reads 12V as output voltage on the other side of the DC-DC converter. That is where you will get the 12V that will be fed into your Arduino’s barrel jack.

Protect From Shorts

I printed a small sled for the converter to sit on and then hot glued the converter to the sled and sled to the frame of the printer. (This was when my printer still worked.) For the time being, you can just put tape on the bottom of the buck converter to keep any solder joints from shorting out until you can print an insulating sled.

With the diode removed no voltage will pass from the Pololu shield to the Arduino. Therefore the Arduino will get all it’s power from the 12 volts of the buck converter. Since it is all tied into the same power supply, when you turn on the printer it will turn on all the different components like it did originally. The only difference is that part of the system is getting 24 volts and part is only getting 12 volts.

Fuses

You need to check that the fuses on your RAMPS board are capable of handling the higher voltage. The fuses are indicated with the red arrow in the picture above. One of these fuses on my board (the one closest to the power plug) needed to be replaced. It can be replaced with another resettable fuse of an appropriate capacity, or a different fuse type altogether. In my case I chose to use a fuse made for car applications.

The original fuse on my board was an MF-R1100 poly fuse. It is rated at 16V and 11 amps. Because the voltage is lower than what we need, then this one must be replaced. The other poly fuse on my board is rated up to 30V; therefore, it does not need to be replaced.

I replaced mine by desoldering the current fuse and making a holder for an automotive fuse. I did this by soldering 2 wires of about 1-1/2 inches (length is not critical) to the board. Then I soldered the other end of the wires to female spade connectors appropriately sized for my fuse. You will see in the picture above that I am using a 5A fuse. I don’t know that this is the right amperage. But I chose a low number to start with so that I can ensure it will burn out before I burn down my house (at least from that component). I will update this when I figure out the right amperage if it needs to be greater than 5A. But at this time I have not seen a definitive answer as to what the new fuse rating should be for 24V.

Conclusion

I said at the beginning of this post that after reading through this you will have a better idea of how to make a better RAMPS choice.

As mentioned previously, you can buy a RAMPS setup that is already made for a 24 volt supply. That is probably the simplest thing that you can do. However, I prefer to have as many discrete components as is practical.

If you are going with one of the cheap RAMPS setups (there are many for $40 or less on Amazon), then here are some of the things to look for.

  • Has 36V or higher capacitors (preferably 48V or greater).
  • Includes LCD (unless you really don’t want one).
  • Includes the stepper driver modules.
  • Includes the Pololu Shield and the Arduino Mega.

The cheap ones will have to be modified. But if you aren’t wanting to do that, then you are missing out on the fun.

Other Resources

I was helped through this step by reading other forum questions and watching videos. This video is one that made sense to me after I had done a lot of other reading. It doesn’t tell you everything you need to know, but it is a great start with this step.

Maybe some of these questions that others have asked will have an answer that makes this step clearer. Here is a Reddit question about the conversion. This forum thread gets a little deep in the weeds, but reading the first response to the question may help clear up what I have posted above.

You can also read this very detailed explanation. It gets into much of the theory as to why you would want to do the conversion. We already know we need to because our printer is already a 24V printer and we have a 24V power supply.

Wanhao / Monoprice Maker Select Plus RAMPS Upgrade: Considerations

This is the first in a series of posts about converting a Monoprice Maker Select Plus (which is a rebranded Wanhao Duplicator I3 Plus) to a RAMPS board. Here are some things you need to consider in doing this upgrade and why you may or may not want to go down this path.

The reason I started through this is that my Monoprice printer stopped working properly (was not getting information from the hotend thermistor). Monoprice ultimately agreed to replace it, but I would have to send it back at my expense (more than $70 in shipping costs). I decided to do this upgrade instead. If you are buying a printer for the purpose of doing this upgrade, then stick with the Maker Select v2 (Duplicator I3 v2 or 2.1). That machine is much easier to convert and there is already a great tutorial on how to do it. You end up with the same features but at $100 cheaper for the original machine.

Considerations

Here are some of the things that need to be considered in this conversion. These may or may not be covered in this order. There is much more to the conversion, but these are some of the decisions you should be thinking about before even starting down this path.

  • My Credentials
  • RAMPS
  • 24 Volts
  • Wiring
  • Firmware

My Credentials

What is my authority for being your guide through this? Almost nothing other than I hope that when I am done my printer works again. Therefore I don’t claim to be an authority on building and modifying 3D printers.

My first, and only, 3D printer is the Maker Select Plus by Monoprice (which is a rebranded Wanhao). I have no experience with any other printer. Mine worked fine for almost 4 months before it died and now I am on a quest to get it up and running again. I am a fan of open source software and hardware. While the Monoprice/Wanhao printer is not completely open source, it had enough modifiable components on it that I knew if it ever came to a dead printer that I could probably rebuild it using parts from Amazon and eBay.

As of the writing on this tutorial, I don’t have my printer working. I am documenting as I go. Hopefully, by the time most people read this, I will have my printer up and running and have corrected any documentation that I find did not lead me to a solution.

With all of that said, I am open to any suggestions you may have on how to improve this information or my rebuild to help others. I have done enough research and tinkering with the hardware to believe it will work as expected in the end.

RAMPS

You will need a RAMPS board for this. RAMPS stands for RepRap Arduino Mega Pololu Shield. It is the basis for many RepRap designs, especially older ones. It is an open source design so that you could build your own, or buy one pre-built. There is a ton of information online about the board and you can get help with just about any aspect of configuration. There are newer control boards than RAMPS with more features, but I did not find any reason that made the newer boards superior for my purposes. Plus, the RAMPS board is so well documented and inexpensive that it is considerably more appealing to me.

You can get them from Amazon, eBay or one of the big Chinese shipping sites like dx.com, AliExpress or Gearbest. Where’s the best place to get one? I don’t know. I would recommend reading many reviews. The one I bought on Amazon has not been overly impressive. There are some obvious quality control issues. Here’s my 3-star review of the product. (The seller has contacted me several times asking me to change the review to something better. So enter at your own risk.)

You will probably want to get one of the kits with a screen, but it is not absolutely necessary if you are using an computer to be your print server. I am using a Raspberry Pi running OctoPi (OctoPrint). The cost is not that much more to get the screen and then you have the option to use the printer without a computer hooked up to it all the time.

You will also need an Arduino Mega. You can buy the shield without the Arduino, but unless you have one lying around unused, you should get a kit with one included.

24 Volts

The Maker Select Plus has a 24 volt power supply. It is supposed to be better for motor control. I’m sure it is, but it also adds to some of the complication of the conversion.

The Pololu shield (the PS of RAMPS) can work with 24V. But the Arduino (AM of RAMPS) cannot. You will need to supply the Arduino with 12V separately. You have to decide how you want to supply the two separate voltages. You will also need to modify the Pololu shield to make it work with 24V and not feed that 24V into the Arduino.

I will cover how I did this in the next post and give you some options for what you may want to do.

Wiring

This has been the tricky part of the conversion so far. The main issue is the breakout board and ribbon cable that come from just behind the print head. The ribbon cable is great in that it simplifies how many separate wires run from the print head to the control board underneath the printer. However, that also means we need to figure out which wires control which sensors and actuators. I have a wiring diagram that I will provide for you in the process of the build.

Firmware

There is a variety of firmware that you could use with RAMPS. In my build I am using Marlin. My choice is made on the fact that I have found quite a bit of information about Marlin and a friend who built his printer from scratch uses a Marlin variant. I can lean on him for configuration help. I may move to a different firmware in the future, but this is where I’m starting.

Monoprice Maker Select Plus: Replacement Followup

A couple of months ago I posted about trying to get my Monoprice Maker Select Plus 3D printer replaced, or at least get a new main or breakout board for it. Ultimately they agreed to replace the whole printer. They don’t have any of the individual components to even repair the printer themselves. That is a shame since that means that otherwise perfectly good printers are sent back to the manufacturer (Wanhao) and never actually get repaired by Monoprice.

Monoprice’s Offer

Monoprice’s solution/agreement was that, yes the printer was poorly manufactured and that it is their fault that my printer does not work. However, because I installed firmware on it, they would no longer cover it under their normal warranty policy. I was welcome to send it back to them at my expense and they would replace it with a new machine.

There are two problems with that: at my expense and new machine. It would cost just over $70 to ship the printer back to them. I realize that if you are not interested in upgrading and modifying your own printer, $70 may seem like a good deal. However, I was probably going to replace all the logic parts on this printer in the future anyway. I like the design of the Maker Select Plus (though if you are doing this upgrade, the Maker Select v2 is the better choice at a cheaper price), but their motherboard and firmware are not the most friendly for hacking purposes. Since I already bought all the electronics to do the upgrade when they had originally convinced me that they would not consider replacement, I would rather move forward with that upgrade path.

The second problem I had with their offer is that they would completely replace the machine and not send me my old machine back. My machine is not perfect (print bed base is bent) but at least I know its quirks and have learned to work around them. I have also done some reversible mods, but I really don’t want to have to disassemble all of my LED and Z-axis upgrades and start over. I would rather have this same machine back.

Definite Main Board Problem

Up to the point of them agreeing to replace the machine, I wasn’t even certain which of the two boards was at fault on this printer. At first it seemed like it was the main board. Then I found a burned electrical trace on the small breakout board as well as a couple of bad solder joints. Since I decided that I would not have the machine replaced I launched into repairing the breakout board myself. I found that the printer still did not function properly after repair. It displayed the exact same symptoms. So the problem is definitely the main board which may have caused the breakout board to fail.

Installing RAMPS

Now I am in the process of installing a RAMPS board and getting it all wired up. (Here’s the board I bought. It seems the manufacturer/seller has some serious quality control issues. Spend more money for a better board if you are able to). Even though the original problem showed up 3 months ago, it took me a month to finally get Monoprice to answer emails and phone calls to come to the decision that I was going to keep it and not have it replaced. Then I began a busy time of work and travel that kept me from doing the upgrade. I am home for a few weeks and will get back to the RAMPS upgrade. I will document what I can here for others who want to convert their Maker Select Plus to an open source control board.

I have actually gotten far enough into the upgrade to be encouraged that this will work as well as I had hoped. I have been able to test most of the motors and sensors with the new board. I am now in the process of assembling the new wiring harness for the machine. I will probably break down the upgrade path into several blog posts. I hope it is a help to the next person who would like (or need) to do this conversion.

And for those who have the Maker Select v2 (or 2.1) or the Wanhao original version of the same thing, there is already a great tutorial on how to do the conversion. If you are looking for a base printer to convert, then the hardware on the $300 Monoprice v2 is almost identical to the $400 Plus (with the exception of the motherboard and control screen which get replaced in the conversion anyway). The Maker Select v2 is cheaper and easier to modify in this way.

Monoprice Maker Select Plus: Burned Breakout Board

I’ve had an issue with my 4-month old 3D printer. I have made heavy use of it and it has performed well…at least until it didn’t. It is a Monoprice Maker Select Plus printer. It is the Wanhao Duplicator i3 Plus that has been rebranded for Monoprice.

Thermistor Reporting Error

About a month ago (from when I am documenting this), my printer suddenly started reporting that the hotend temperature was 58° C no matter what the temperature actually was. It seemed likely that it was the thermistor itself since they seem to short out or go bad according to my reading. And they are so cheap that it is worth trying with a replacement.

I did not have a replacement yet, so I did some testing. The thermistor performed as expected when it was removed from the printer. Yet when the thermistor wasn’t even plugged in, the printer and OctoPi reported the hotend at 58°. Everything pointed to the main control board as being the problem.

It was a Sunday afternoon and Monoprice support was not open. So, it seemed reasonable to contact them via email. After waiting a couple of days with no response, I tried contacting them via chat. The chat sessions kept timing out. Presumably because there was no one available to help at that time.

Carlos from Monoprice finally got back with me by email on Thursday (4 days after my support request). He asked for more information and what exactly I had done to test for the problem. When he replied again on Friday it was agreed that the problem seemed to be the mother board. I would have to send in the whole printer for replacement and not just the board.

Well, in the mean time of waiting for support that I thought would never come, I reflashed the board to the Wanhao firmware (Monoprice has not released a firmware to the public even though theirs has had a typo in it since the printer first released). Even with the Wanhao firmware the symptoms were exactly the same. And, as a result of reflashing my board, I voided my warranty. So on Friday of that week, Carlos said that I could not get the board replaced under warranty. On top of that, Monoprice did not even have boards available they could sell me. They suggested that if I wanted to get a new board to buy it directly from Wanhao.

RAMPS Upgrade

I started down the path to upgrade to a RAMPS control board. Ultimately that is where I will probably go with this printer. But for the moment, while making the conversion to RAMPS, I found a definite hardware issue that I thought Monoprice would like to know about.

Monoprice Support

I started a new support request email. This time on a Saturday because that is when I discovered the problem. They don’t have phone support on the weekends. After sending the support request I got a message saying that Monoprice support would get back with me within 1 business day.

On Thursday of the same week (today) I tried Monoprice support chat again. Between the last attempts and the attempts today, I probably tried to use their chat 6 or 8 times. Each time the session timed out without an explanation. I assume that it is because no one was available to help.

I called and was put on hold for only 7 minutes. For which I was very thankful. Israel answered and I started off by telling him that I was trying to follow up on an email support request. I gave him the ticket number and he was able to find my email. He apologized for their support being slow but that they were very busy. “Then,” I said to him, “don’t tell me that you will get back with me within 1 business day.” He agreed that something should be done about the message. What would be better, in my opinion, is to hire enough qualified people who could help them stay caught up.

Cold Solder Joint

While I don’t have much hope that Monoprice will replace the broken part on my printer, I did still want to do the responsible thing and let them know they had a problem. I believe my printer failed because of a manufacturer defect and I wanted to send them pictures of what was happening. That was the nature of my second request for support. Of course, I hope they do replace the bad part, but I have been in the warranty-voiding business for approximately 37 years. So I am used to it. In fact, this may be the first time that I have approached a company about warranty work. I usually try to fix it myself if it is something worth keeping.

Picture of a bad solder joint.

What I discovered were some poor solder connections. As you can see in the picture, there are at least 2 bad solder joints. One of the bad solder jobs is on the thermistor connector. No surprise. I have confirmed that there is no electrical conductivity from that pin to the ribbon cable connecting plug.

You also see that the connector is red. It is the only connector on the breakout board that is not white. I wonder if other Monoprice/Wanhao boards are like this?

Burnt Trace

On the top side of the board there is a burned electrical trace. You can see in the picture below that there is an enamel coating on the board. But one trace, which happens to be for the thermistor that is not working, is burnt.

Picture of a burned electrical trace

What will Monoprice Do?

Again, I contacted Monoprice today to let them know about the problem and to see if they would at least replace that small breakout board. This board, by the way, is behind the print head and is only about 1.25 by 1.75 inches in size.

Israel said that I could send my pictures to him and he would pass them along to the next person. He also told me that the breakout board was not in stock at this time, but that I could call back on Monday and see if they had a projected date of getting more stock.

I dutifully sent my pictures to Israel today at the email address he provided. It is now 8 hours later and I have not heard back from him. A simple “thanks for the pictures” would have been nice.

We’ll see what happens.