odd temp sensor bed error

[lance-greene 7]

so lately every so often one of our UM2's gets a "temp sensor bed" error. ive checked the connections and they seem fine. and after a couple restarts the error stops happening for awhile

One thing i noticed though is that if it does happen (which is maybe every 10 prints or so) it always happens at the exact same point. It happens when the bed is rising from its home position at the start of a print. the bed rises about 1/3 of the way then there is a noticable judder that happens which is exactly when the temp error triggers. the bed continues rising to the nozzle and the nozzle purges as normal, but when it moves to the print start position it halts from the error.

any help?

[Torgeir 280]

Hi Lance,

Two weeks ago I've changed the "24" VDC master relay on the main board (UM2). This relay can make lots of troubles and give all the warnings related to the "power" users of 24 VDC and those are: All of the stepper motors, and all three heater's (three if you have a Mark 2). There is actually no warning telling you that the 24 VDC (from the master relay) is missing, this could be a good thing to add into next generation hardware/firmware..

The thing is that if this relay starting to arching (voltage is dropping over a certain time), any of those warnings can shows up due to a missing or interupting 24 VDC and such warning is actually false and misleading.. As I had this problem, got all kind of "strange" warning until I realized all of them had a common power source and all of them was powered via the 24 VDC relay.

The funny thing is this; one day when feeding the filament using the advanced menu I could have an error saying: X or Y end stop error and then the firmware halted with an error number I cant remember, but..

Later on, this one;

ERROR - STOPPED

Heater error

Go to:

ultimaker.com/ERØ3

The printer may be switched off, then on again and may work for some time, but you will sooner or later have a total failure of this relay that have to be changed.

As I had to go to KL (Kuala Lumpur) for a week, I used this opportunity to search for this kind of relay.

I found two brand of this relay type:

1) SRD-05VDC-SL-C Blue colored plastic housing (Brand name Songle)

2) HK3FF-DC5V-SHG Black colored plastic housing (Brand name HUI KE)

The coil voltage is 5 VDC and contacts current is 10 A at 30VDC

However, I've also found that this same relay (the one with the blue colored plastic housing) is used in the Arduino relay modules, so this migt be handy to know for someone..

So to a little warning; this relay is not that easy to remove without damaging the PCB track. Here you will need some special skills and tools – now you're warned!

I made some pictures of the repair, if of interest I'll add them here.

Well, just my 5p.

Good luck.

Thanks

Torgeir.

[lance-greene 7]

yes id love to see some pictures. im sure we can fix it

[Torgeir 280]

Hi Lance,

Here is some pictures of the process.

This is the first error I've got.

Here is the faulty relay K1.

Faulty relay removed from PCB, solder to be removed from mounting holes.

New relay installed beside the heating outputs, 3 ea.

The stepper motor output drivers, 5 ea -and all seven receive power from K1!

This picture is made just before the PCB cover is installed. (Note, there is no brownish color around the stepper drivers due to heat, could this be due to the two fan installed?)

This last picture show the two brands of relay I found, including the Arduino 2 relay module holding same types of relay as installed on the PCB I have in my printer.

 

OK., this was all and good luck.

Thanks.

Torgeir.

[lance-greene 7]

well I also bought a 4 relay arduino module, im removing the printer board now to install the new relay, hopefully it works

[lance-greene 7]

so i changed out the relay, and it didn't solve the problem. luckily doing this didnt make anything worse though. so I'm back to square one.

[Torgeir 280]

Hi Lance,

I'm very sorry to hear this.

As I've read trough your description of the failure, this must be a kind of slow heating (restricted current) that is detected over "some time" by the firmware that stop the program due to a heater failure. Could this be the power wires for the heat bed, connection at the bed terminal or at the main PCB. If there is such a failure there is always some sign of overheating where the failure occur. Color change, brownish burnt etc. Also look at the feeder cables, if there is an interrupted connection along the cable some place you will see this easily. Since this occur at a certain level of height, the failure might be in the bed power feeder. Look at the strain relief at the bed as the wire tend to break here or, at the other place where the wire also may bend in the inner left corner.

The error code / observation is just the same in both cases.

Hope you find the problem and good luck.

Thanks.

Torgeir