This is the first error I've got that isn't a service call, so it seems like this one should be easy to fix. The ambient temperature is room temp, so that's not the problem. Seems like a faulty thermistor or something so I'll try to locate that and check the connections. Got any ideas what the problem might be?
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This Old Roland (LEJ-640FT) - Temperature Is Too High
- Thread starter Lucid
- Start date
I founds the ambient thermistor which is the one reporting the high temperature. It's located underneath the display panel and plugs into the "Motsens Junction Board". Currently the temperature says 104F, so I disconnected the thermistor from the motsens board and restarted the machine. The temperature was still 104F, so there is definitely a problem here. If the same value is being read with or without the sensor plugged in, then it's not working right. Now I'm not sure if it's the "Motsens Board" or the thermistor . I used a multimeter to check the resistance value of the thermistor and found it to be 12.46 kiloOhms. I'm not sure what it's supposed to be because I can't find a data sheet for this thermistor. However, other values for other thermistors I found on the internet were in this range, so it's possible the thermistor is good.
A new motsens board (W701588240) is about $100, and a new thermistor (23415133) is about $40, so there isn't too much risk here.
A new motsens board (W701588240) is about $100, and a new thermistor (23415133) is about $40, so there isn't too much risk here.
Solventinkjet
DIY Printer Fixing Guide
In my experience when Rolands give the temp too high error it's actually the head thermistor and it's heating up because of a short circuit. Check your head cables for damage or ink splatter on the leads. It could just be a failing head as well.
Thanks for the suggestion. I won't rule out the head just yet, but here is why I think it's the ambient temp.
I entered service mode and went into the service menu. In there, there was an option for "thermistor check" so I did that. In there, there were 3 options, Head, Board, and Ambient. Both Head and Board were reporting numbers around 70F (seems reasonable) but the Ambient was reporting 104F. 104F just so happens to be 40C, or the maximum operating temp of the machine, so it seems to just be a default reading when something isn't working right.
I ended up taking the ambient thermistor out and measuring the resistance at 3 temps. One with a bag of ice water on it, one at ambient, then one with a bag of warm water. The values I got were 20.8 kiloOhms, 12.43 kiloOhms, 6.5 kiloOhms respectively, which all seem reasonable and move in the direction you would expect. So I'm assuming the thermistor is good. At this point, I'm thinking its probably the Motsens Junction Board it plugs into. I ordered a new one, so I'll let you know if that works.
Here is my thermistor with an ice water bag on it.
Here is the board the thermistor plugs into.
Update: "Temp too high" still not fixed.
I finally got the new Motsens Junction Board in. I got it installed and got the same "temperature is too high" warning. Again, according to the thermistor check I did from the service menu, this is from the ambient temp thermistor. The head thermistors and board thermistors both checked out okay. I guess the next logical step is to replace the thermistor. I would have done that first, but based on my test with the multimeter, it seemed fine. Maybe there is just a bad connection somewhere. I'm going to order a new one and will post back here.
I finally got the new Motsens Junction Board in. I got it installed and got the same "temperature is too high" warning. Again, according to the thermistor check I did from the service menu, this is from the ambient temp thermistor. The head thermistors and board thermistors both checked out okay. I guess the next logical step is to replace the thermistor. I would have done that first, but based on my test with the multimeter, it seemed fine. Maybe there is just a bad connection somewhere. I'm going to order a new one and will post back here.
Update: Moving on from this error/warning
It's been a while since I've updated on the status of this. I'm just now getting more time to work on this again. I was able to talk to a service tech about this issue and explained that I changed out the thermistor, even though the other one seemed to be working fine, and changed out the Motsens board it plugs into. He believes the error is actually a software error and the the board needs to be re-flashed. That seems to make sense to me too given everything I've tried.
However, he also said I should be able to print in Service Mode as is, so I'm going to get some ink and move on to that to see what other things need to be fixed. I possibly need new print heads and cap stations. After everything else is running fine, I'll work on re-flashing the board. I'll post a new thread with any other issues I run into, but will update here when I get around to re-flashing to see if that fixes anything.
It's been a while since I've updated on the status of this. I'm just now getting more time to work on this again. I was able to talk to a service tech about this issue and explained that I changed out the thermistor, even though the other one seemed to be working fine, and changed out the Motsens board it plugs into. He believes the error is actually a software error and the the board needs to be re-flashed. That seems to make sense to me too given everything I've tried.
However, he also said I should be able to print in Service Mode as is, so I'm going to get some ink and move on to that to see what other things need to be fixed. I possibly need new print heads and cap stations. After everything else is running fine, I'll work on re-flashing the board. I'll post a new thread with any other issues I run into, but will update here when I get around to re-flashing to see if that fixes anything.
I would spray a little freeze spray on the thermistor
Quick 30 second test, see if reading changes
Wiring could be damaged, ink on cable?
Quick 30 second test, see if reading changes
Wiring could be damaged, ink on cable?