MakerGear Forum

Hello everyone,

The 19v PSU for my Makergear is very rapidly declining. I'm talking to some very helpful people that might be able to send me a replacement, but in the meantime I'll need my printer online this weekend. My machine is using a rambo 1.1b and a single e3d v6 extruder.

This page: http://makergear.wikidot.com/m2-electronics would imply that I can use in anything from 12-35 volts to power everything. However I want to confirm this before potentially frying the board due to some misunderstanding!

Would a computer PSU's 300 w 12 V line work until a replacement arrives? If not, what should I be looking for? I have a box of ac/dc converters, closest I could find was a 16 V 4.5 A brick.

Thanks for any and all help, really need to get this thing working properly!

helix_3 wrote:use in anything from 12-35 volts to power everything

Although the RAMBo can use anything in that range, the 19 V supply runs the steppers and the extruder heater, neither of which take kindly to different voltages.

A lower voltage produces poorer stepper performance, particularly in the old Z axis motor that (I think) your M2 uses. Although a higher voltage improves stepper performance, in either case you may need to re-tune the acceleration and maximum speed settings to get the same print quality.

The extruder heater has a resistance selected for 19 V. The power dissipated in the heater varies as the square of the voltage: a 12 V supply reduces the power to 40% of normal, which means it'll take much longer to heat up and may not be able to maintain the proper temperature. The PID control loop can only do so much: if there's not enough power at 100% duty cycle, the extruder won't get hot enough.

Bottom line: the 16 V supply brick will probably work. Its 4.5 A current rating seems a bit low; if the supply suddenly shuts down, its overload monitor is working. Watch for stepper stalls and low extruder temperatures.

And do an absurdly good job of insulating those 120 V AC terminals; if you drop something conductive, you know where it will land!

Good luck...

ednisley wrote:

helix_3 wrote:use in anything from 12-35 volts to power everything

Although the RAMBo can use anything in that range, the 19 V supply runs the steppers and the extruder heater, neither of which take kindly to different voltages.

A lower voltage produces poorer stepper performance, particularly in the old Z axis motor that (I think) your M2 uses. Although a higher voltage improves stepper performance, in either case you may need to re-tune the acceleration and maximum speed settings to get the same print quality.

The extruder heater has a resistance selected for 19 V. The power dissipated in the heater varies as the square of the voltage: a 12 V supply reduces the power to 40% of normal, which means it'll take much longer to heat up and may not be able to maintain the proper temperature. The PID control loop can only do so much: if there's not enough power at 100% duty cycle, the extruder won't get hot enough.

Bottom line: the 16 V supply brick will probably work. Its 4.5 A current rating seems a bit low; if the supply suddenly shuts down, its overload monitor is working. Watch for stepper stalls and low extruder temperatures.

And do an absurdly good job of insulating those 120 V AC terminals; if you drop something conductive, you know where it will land!

Good luck...

Thank you for the help! I went to a junk shop bought a very similar voltage supply (18.5 v/ 6.5 A) as a replacement, and things seem to be working perfectly.

helix_3,

Glad you got it working! (Sorry I couldn't find my old brick to send you. Watch, tonight I'll go home and it'll be "right there" where I left it. )