GT2560 Rev A+ Voltage Drop with heated bed.

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Ingybing
Posts: 5
Joined: Wed Jun 27, 2018 5:39 pm

GT2560 Rev A+ Voltage Drop with heated bed.

Post by Ingybing » Sat Jan 26, 2019 4:06 am

Hi,

I was wondering if anyone else has come across this problem and has a solution. I've upgraded my i3 Pro B over time and dialled in the print quality to a point where i'm really happy and getting some nice fine prints. However i realised some issue i had recently were when using the heated bed. I've mostly been printing PLA so not needed it... but was having trouble with a print not sticking so was using the headed bed but noticed i get ripples appearing in the surface of the print. If i turn the heated bed off everything is smooth again. I notice when the heated bed powers on to warm up the Fan RPM drops.... i popped the multimeter on a fan output and can see the voltage dropping from 12v down to 11.6v when the heater is on. I thought it was maybe with my mods i was tipping things over the 15amp power supply max and thats why so i replied it with a 30a supply... still no dice, the voltage drops when everything is on and i still get ripples in the print as it seems to be knocking on to the extruder motor so the amount of plastic is never constant so thats causing the ripples and funky first layers (ok then under extruded then ok then under extruded etc while doing the bottom infill. The under extrusion coincides with the heated bed coming on and going off).

Have i just got a bad board or could something else be causing this? Anyone got any suggestions for things i could try?

No heated bed print: https://1drv.ms/u/s!AqCG82v0fgkk12dg4eKCAzK0PMyl
50 deg heated bed: https://1drv.ms/u/s!AqCG82v0fgkk12ZtMfPJ9vYKUrp8

you can see theres quite a difference in the quality.

Ingybing
Posts: 5
Joined: Wed Jun 27, 2018 5:39 pm

Re: GT2560 Rev A+ Voltage Drop with heated bed.

Post by Ingybing » Sun Jan 27, 2019 7:57 pm

Measured the voltage across the potentiometer and gnd on stepper driver and that’s dropping by 0.002v as the heater comes on. Is that normal?

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