MakerGear Forum

Ok any suggestions what might be wrong , my heating bed won't heat up. Using Ponterface click on the heat button and nothing happens.

First, make sure that pronterface is showing a room temperature measurement from the heated bed; if so, then it's not the thermistor.

The usual reason heated beds stop working is a broken wire, which is usually an internal break due to wire flexing, so you can't see it. Unplug your heater and (hopefully you have some sort of voltmeter/ohmmeter?) read the resistance across the leads of the big red plug. The 24V heated bed plate should read 3 ohms, the 12V heated bed (the older model) reads 1.5 ohms. If it reads infinite resistance, or you can't get a good reading, you have a broken or intermittant contact (note that the break almost always happens close to the bed, because the wires flex there more than anywhere else).

A somewhat more rare occurrance is a faulty power transistor, which may be the case if the heated bed plate appears to read the correct resistance. But broken wires often produce intermittant contact, which can be annoying to diagnose, since it's possible to read a perfectly good resistance when it's unplugged and then have an open circuit again when you plug it back in.

Mine stopped working today as well. One of the wires broke right where it connects to the bed. I soldered it back and it is working fine, but I feel like I need to make some changes to take the stress off of the connection.

If you look through the Modifications section, there are several creative solutions for reducing the flex on the bed plate wires so that they don't break as easily. I used Jim's method here, which just requires a couple of extra zip-ties. (My printer's about 10 months old, and so far - so good.)

viewtopic.php?f=7&t=1712

There are other solutions too, if you have a bit more time, including a cable-chain setup, and printed braces that secure the wires - just check out the Mods section.

Jules wrote:If you look through the Modifications section, there are several creative solutions for reducing the flex on the bed plate wires so that they don't break as easily. I used Jim's method here, which just requires a couple of extra zip-ties. (My printer's about 10 months old, and so far - so good.)

viewtopic.php?f=7&t=1712

There are other solutions too, if you have a bit more time, including a cable-chain setup, and printed braces that secure the wires - just check out the Mods section.

That's right along the lines of what I was thinking. Good to know it works.