Printing fine, then, undervoltage event

iveyforce

@dc42 said in Printing fine, then, undervoltage event:

Does the Duet report the VIN voltage at 9 to 11V all the time? or does it report 24V most of the time?
Have you measured the voltage between the terminal block screws, to check that you are really getting about 24V there?
Is there still 24V there even with the bed heater running at full power?

When I turn the machine on, it reports between 13-14v. If I rerun M122 every 60 seconds-ish, it drops about 1v each time, until it bottoms out around 9.5v. It doesn’t actually fail until I start a print.
Yes, I measured at the terminal block screws: 24v
Yes, turned on bed heater and hot end and both measure 24v at the screws for the entire preheat. Meanwhile, M122 shows voltage dropping.

Edit: @Phaedrux tried the other psu, no change

T3P3Tony

@iveyforce thanks. Doe the hotend and bed temperature sensors read around room temperature before you start heating anything?

Can you send through an image with this part of the baord in focus:

especially R80/R81/C79

iveyforce

@T3P3Tony ![alt text]( image url)

At work right now, but I had taken this this photo after I disconnected everything to see if the issue was caused by wiring. I since removed the heater wiring, and I'm having the same symptoms with just a bare board.

iveyforce

Not to be presumptuous, but I submitted the Duet3d warranty form provided by reprapworld.co.uk yesterday. I'm having a hard time sitting on my hands waiting for responses.

bot

Have you got insulating washers under those massive button head cap screws?

dc42

There's also a possibility that the problem is the 7.5A (brown) fuse. Can you measure the voltage between each leg of it and the ground terminal on the VIN block? There should be +24V on both legs.

iveyforce

@dc42 It reads 24.3 on both sides of the fuse.

Not sure what else to do here...

iveyforce

@bot yep, insulated.

iveyforce

@T3P3Tony

Here is a better shot of the area you requested

dc42

Thanks for your patience. I approve a warranty replacement for your Duet.