Need help with bed heater

As I mentioned in another post, I am working on extending the Y axis on my Taz4. I’m gunning for around 450mm maybe 500mm. One roadblock is the bed heater. A 300mm x 450mm 24 volt heater is a couple hundred dollars on the rare occasion I can find them. I was thinking I could build one so I got to calculating in my head how much resistance the element would have to have to limit 24 volts to 10 or so amps (2.4 ohms). That said, I measured with my multimeter and it shows .001 ohms across a stock 24v heater. Obviously there is something I am overlooking or simply mis-understanding. Any help will be appreciated.

Hello gg,

You must have an issue with your bed heater. The reading you should get when you set your meter to 200 ohms or less should read ~1.7ohm.
The thermistor will read aprox. 100k ohms at room temp.

If your bed heats up, then something is up with your meter. If the bed does not heat up, then it will be due to a bad heater.
Hope this helps.

Thanks, it was operator headspace and timing. I measured 1.8 once I set my meter correctly.

Do you know what type the bed thermistor is?

The bed thermistor is non replacable. ( not sure if that’s a word) The entire heat bed will need to be replaced.
you can get a new one with PEI installed. Please make sue that the thermistor is the issue before you do, so that you don’t have the same issue once you install the new one.

I’m not looking to replace it, I’m building my own heater and need to know what type the Rambo is set up for.

It uses(set for) the same type of thermistor as the extruder uses. The Semitec 100K NTC type.

Good, I have one of those