3-in-1 GT2560 voltage

[interstice2718]

Hi,

I have the 3-in-1 control box. With the power supply outputting 12 volts, I measure 11.5 volts across the heatbed terminals when it is on. Can I turn up the voltage from the power supply a little? Say to 13 volts?

The reason is that my heatbed temp seems a little low.

The GT2560 documentation says input can be 12-24v, so I think this should be OK, but thought I would check first.

Thanks

[Mark]

You might need to check the heatbed resistance first, if it's too big then it won't reach the temperature. Check out this link to measure it:
http://www.geeetech.com/forum/viewtopic ... 19&t=17039

[interstice2718]

Hi Mark,

The heatbed measures 1.4 ohms across the red wires, cold.

When set to 115C in Repetier (as measured by the built-in thermistor), the aluminum bed itself only goes to 75C, as measured with a thermocouple. That's as hot as it goes, ie setting Repetier to 117C results in no additional heating.

I figure there's some drop across MOSFET, maybe I can increase voltage from power supply to get heatbed voltage up to 12volts.

[Mark]

You can try to increase it to about 13V, but not too high or it might damage the board or PSU.