Heat bed suddenly stopped working
In the middle of a print, the heat bed suddenly stopped working. Everything works fine with the exception of the heat bed
Troubleshooting:
- LED on heat bed connector - No
- LED6 on mini-Rambo - No
- Power input (X10 AB, and X10 CD) – 12V, Molex connectors ok
- F3 Fuse (15A) – Ok
- Terminals on heat bed - Ok
- Heat bed cable – Ok
- Heat bed resistance – 0.9 Ohm
- Heat bed connector (X3 AB) – OK
- 12V3 – 10.55V when idle, 11.85V when heat bed and hot end is set active
I have gone through the wire diagram and verified all component, where everything seems to be ok. The mostfet is difficult to test without de-soldering it, but there are no short circuits which would be natural of a mosfet failure.
What I did found was that the PWM output (port 1) on the Atmel I only gave 0,85V when heat bed was supposed to be on. When the target setting is set well above the thermistor readback, I would expect something in the range of 4.5-5V?! The PWM output (port 2) for the hot end shows 4.99V when activated.
I have done a factory reset and upgraded to the latest firmware – heat bed still not working
This is actually the second time this happens – last time I replaced the mini-rambo with a second hand piece I got my hands on.
Any thought? Please help.
RE: Heat bed suddenly stopped working
Any success? Have you contacted support via chat?
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Chuck H
3D Printer Review Blog
RE: Heat bed suddenly stopped working
That was what happened to me a few times before my PSU capacitor died. I had to get a new PSU. I inserted the one that I purchased because Prusa does not carry the PSU for the MK2 anymore. Good luck!
https://smile.amazon.com/dp/B00D7CWSCG?psc=1&ref=ppx_yo2ov_dt_b_product_details