Prusa i3 restarts once hotend and heated bed reaches temp

I've had this problem since installing the heated bed, it heats up fine hot end heats up fine, but when ready to print it resets itself. If you print without the heated bed it works fine. Any ideas anyone????

Thanks

What is the amp capacity of your power supply?
What are the max temp settings in your firmware?

1) Just after the restart have a feel on all the wiring going into your control. Especially any connectors. See if they are hot.

2) Verify all screw terminals are completely screwed down.

3) Try to heat-up the heatbed and then turn it off to see if that also makes it restart.

4) Try to change the regulation mechanism so that the heatbed is bang-bang instead of regulated.


Strange restarts can happens when you are pulling high current and not having a perfect connection together with the pulsing on/off for keeping the heatbed temperature.. Think of it like a big water tap - It goes fine as long as the tap is just open, but as you start opening and closing that water tap real quick you put a lot more strain on the piping.



I don't suspect your power-supply right away because almost all power supplies have circuitry that shuts-down the PSU on failure - It does not restart.

I will try feel the wires again tonight see if they are hot after the restart. All the terminals are screwed down tight, hang the bed on its own doesn't restart only if both bed and extruder are on. Amd in a little lost with the regulator mechanism you said. What's that? Also the psu im using is a xbox 360 one and has been fine so far.

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waynes
I will try feel the wires again tonight see if they are hot after the restart. All the terminals are screwed down tight, hang the bed on its own doesn't restart only if both bed and extruder are on. Amd in a little lost with the regulator mechanism you said. What's that? Also the psu im using is a xbox 360 one and has been fine so far.

With regulation mechanism I meant to say the firmware control of the heatbed. You can change how it turns the heatbed on and off so that it uses a much cruder control (bang-bang).

Do you have USB power on your control board? With USB power your firmware should still run despite the PSU falling out.

Try a print with the bed at, say, 60C. Let it get up to temp. If that works, it's probably a power issue. If not (if it restarts), it's probably firmware.

To me, it looks like the 5V regulator is right at the edge , when it has to power "all at once"
Did you measure the 5V rail?
Probably the restart is caused by a failing 3.3V regulator that powers the SD-Card? This 3.3V regulator is again fed by the arduino 5V.

If you happen to have a power hungry SD-Card, it can cause hangup/restart, right when the print should start...
-Olaf

o_lampe: The printer probably reads from the SD as soon as the print starts, before the heaters are up to temp.

So it could be the sd card that's causing the issue, I have tried from my laptop and it seemed to work ok. I will try another sd card and see if the issue remains.

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epicepee
o_lampe: The printer probably reads from the SD as soon as the print starts, before the heaters are up to temp.

Yes this is correct, but the other power hungry consumers are off by then, right? My theory is, "all at once" powered is too much.
-Olaf

If it is that then a new psu would make it work.

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waynes
If it is that then a new psu would make it work.

No, the 5V regulator on the arduino would still be weak.
A separate 5V UBEC would help.

HI, just need help, I'm having same issue and currently as even using SD or change SD and even use laptop, after heat up and going to start the problem restart keep happening. Any advise how to solve the issue?