I currently have 4 workhorses down with the same issue. They all failed within about a day of each other.
I manually set the nozzle temperature to 255C and the nozzle is heating up, getting to roughly 228C before stalling significantly, increasing maybe one degree per 30 seconds up to 230C, then sending the error message “Heating Failed: E1, Printer Halted, Please Reset”.The nozzle is clean. The fan is not running. Over 10 other workhorses are able to get up to this temperature just fine.
I have replaced the thermistor and heating wires and checked continuity to the motherboard for each printer, but am still getting the same error. In the past this has been able to fix this type of issue.
My thought is the newest firmware may be causing the issue since the printers went down so suddenly and all with the same problem. I flashed all the printers to the Marlin 188.8.131.52.13 firmware a few weeks ago. If anyone has a link to where I can download an older version of the workhorse firmware that would be greatly appreciated.
If anyone has any ideas or is dealing with similar problems please let me know!