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.
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.
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.
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?
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.
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.