Preheat Error
My Mk3S recently started giving a PreHeat Error when setting the temp. The screen shows no increase in temperature. The red light on the bed does not light. Power cycling the printer has no effect.
I have also tried several things to resolve this:
- confirmed with hair dryer that thermistors in hotend and bed are still working
- tried repositioning of both wire bundles to see if there was a frayed wire / short
- replaced heater core (just in case it had an issue)
- replaced thermistor in hotend (just in case it had an issue)
- confirmed with hair dryer that new thermistor in hotend is working
- unplug / replug hotend thermistor from board - this seems to allow heatup of hotend and bed for a few mins for not long enough to finish a 20 min print.
- unplug / replug hotend heater core from board - no effect
- unplug / replug bed thermistor - same as hotend thermistor
How can I fix this...
RE:
If you are not getting any voltage to the bed, you have an EINSY problem or the wires have broken internally from flexing over and over. If you are, your bed is burnt out.
RE: Preheat Error
Have you checked the fuses ?
RE: Preheat Error
I did check the fuses visually and swapped the 5A fuses. No change in behavior.
I will pull out the multimeter tomorrow and check thermistors, heater and fuses
The red light on the bed does not light.
This suggests power is not getting to the bed. Can you put a multimeter across the heatbed connectors on the board [two screw connector at bottom right] and measure the voltage? The bed must be set to heat, do it both with the heatbed connected and without.
Cheerio,