UM2 Machine shuts down when trying to heat the bed

[gregwar 1]

Hello,

It looks like my machine (Ultimaker2) shuts off when I tries to heat the bed, as in the following video:

 

The oscilloscope is showing the input voltage which drops to 20V just before the printer restarts.

When it is not connected, the machine doesn't shuts off, and I can clearly see the heater bed connectors going from 0 to 24V.

Note that I can heat the nozzle without any issue.

What can be the cause of this? Any Idea?

I've also measured my hot bed resistor which is 3.3Ohms, is that normal?

That would mean that 7A should be consumed by the bed to heat? It sounds a lot, knowing that the power supply is only 10A.

Additional info: the power supply blue led light is lower when the problem happens, can be its fault?

EDIT:

I'm trying to print with cold bed, seems to works so far, I think the problem is the power supply

I've ordered a 720W (24V/30A) PSU from eBay to try replacing it

Edited January 3, 2016 by Guest

[korneel 176]

while it does sound like a power supply issue, can you try to reheat the points where the bed connects to the wiring?

did it ever work before?

is this a new machine or is the machine approx 1,5 to 2 years old?

[gregwar 1]

The machine is approx 1.5 2 years old

It worked before

What else do you think it could be?

[korneel 176]

either the heated bed has died but I'm putting my money on the flux.. try reheating the solder joints.

[gregwar 1]

either the heated bed has died but I'm putting my money on the flux.. try reheating the solder joints.

 

In this case it would just not heat, right? Why would it shut down?

Moreover, is 3.3ohms right?

[korneel 176]

 

either the heated bed has died but I'm putting my money on the flux.. try reheating the solder joints.

 

In this case it would just not heat, right? Why would it shut down?

Moreover, is 3.3ohms right?

 

I've had a machine here that would also shut down as soon as the bed heated up because of bad connections. hence my suggestion and my correct guess of the age of the machine seems machines that are now 1,5 to 2 years old are suffering from weak solder joints in the heated bed..

don't know the Ohm's by heart to be honest

[gregwar 1]

OK, And the solution is just re-heating the solder on the bed side?

[neotko 1,417]

Also just in case. Check that the bed screws ain't too tight that the bed connectors are touching the aluminium.

Mind the gap

If it's touching it can affect the solder points. Ofc there's no need to leave a gap like that photo. Some gap will do.

Edited January 4, 2016 by Guest

[korneel 176]

OK, And the solution is just re-heating the solder on the bed side?

 

yes.

@neotko

great point! it will also make your bed unlevel if it's touching