Random temperature drop, firmware disconnection on Taz 5 Dual v2?

Alas, another 2 issues with this Taz 5 Dual v2 I’ve been working with. It seems determined to put me in an early grave.

There has been this issue with the Taz randomly disconnecting itself. I have reinstalled the firmware and checked its accuracy more times than I can count, to no avail. It randomly does this all the time, at least once a week.

Is it more likely an issue with the board, the drivers, or the computer/usb?

See the image where it says “firmware unresponsive” in the communication log, then where I issued an emergency stop…

So it appears that T0 can’t hold its temperature. It will be set to 235 and print for about 30 minutes or so, then it drops to roughly 225, 226 and struggles to get back to 235. This happens a few times over the course of a print.

Obviously its something wrong with the hot end… but which part? Should I just replace the entire hot end? Or is it something else?

Keep in mind I’m using S3D here but the problem happens no matter what slicer is being used.

Could this connectivity failure have anything to do with the temperature drops as well?

Thanks all!

If you have access to a digital multimeter, you can check the resistance measurements on the tool head to see if the thermistor or heater cartridge is bad. With the printer turned off and unplugged, disconnect the hot end from the wiring harness and test hot end for the proper resistance. The smaller wires coming from the hot end are for the thermistor and should read ~100k ohms at room temperature. The larger wires are connected to the heater cartridge and should read ~20 ohms. That should help you narrow down if this is an issue with the hotend itself or an issue somewhere else. If those measurements come back okay it could be a break in your wiring. To test that you can take those same resistance measurements but where the wiring plugs into the control board to see if you are getting the same readings. It helps to move the wire around when you are doing this in case the break is intermittent.

Alrighty, I will give that a look-see here shortly once I get my hands on a multimeter (don’t have one at my location at the moment). That will then give us some hints at where to go in regards to the heating issue.

Any tips for the firmware unresponsive/connectivity issue? Maybe the whole board is going bad? This machine has seen better days.