[quote=“ntoff”]I just got through making the opto-coupled version to supply 24v to the heatbed. You might not need this step but since absolutely no one local sells spare parts for this thing I can’t risk frying my controller board.
Reaches temp really quickly but one concern is the bed is unevenly heated. In the center where the fans are, the bed is much cooler than at the extremities. Has anyone ever tried to add more temperature sensors to the bed, get an average temp and then send that average into the controller board? Yes the bed moves around so it’s not always in the center of the bed, but I mean the part of the bed near the fans is always a lot cooler. So if the temp sensor is under the cooling fan then the rest of the board gets really hot, if the temp sensor is away from the fans then the part of the board under the fan is under temperature.[/quote]
Using a glass surface will help keep the temperature even across the bed. The thermal mass increases a lot with the addition of the glass. After switching to a glass surface I installed a fan that I use to cool the heat bed after a print. The glass was taking a long time to cool down and release the printed object.