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Hot end questions
Posted: Sun Sep 03, 2017 9:03 am
by barry99705
Do thermistors and heater cartridges slowly go bad, or just all at once? In the last month or so, I've had problems keeping temperature. Yesterday I had two prints quit because it couldn't keep up. Printing with an e3d v2, .4mm nozzle, 50mm/s perimeters, 55mm/s infill. All this is wired through seeme's he280 accelerator board. I really wanted to like that hot end, but couldn't keep the fuse ferrules tight.
Re: Hot end questions
Posted: Sun Sep 03, 2017 9:57 am
by geneb
Do you have a sock on the heater block?
g.
Re: Hot end questions
Posted: Sun Sep 03, 2017 10:28 am
by barry99705
Yep. Just for giggles I unplugged the part cooling fans and that helped a little, but it's still not keeping up.
Re: Hot end questions
Posted: Sun Sep 03, 2017 10:59 am
by Mac The Knife
It wouldn't hurt to double check the hotend connections at the RamBo board,,,,
Re: Hot end questions
Posted: Sun Sep 03, 2017 2:51 pm
by barry99705
Yea, that was the first thing I checked. They're tight.
Re: Hot end questions
Posted: Mon Sep 04, 2017 10:25 am
by geneb
I'd almost suspect the power supply if it's a v2. Can you try monitoring the 12v rail while you're printing?
g.
Re: Hot end questions
Posted: Tue Sep 05, 2017 8:15 am
by barry99705
I'll give that a shot, will update later.
Re: Hot end questions
Posted: Wed Sep 06, 2017 5:29 pm
by barry99705
Hot end connection bounces between 11.55vdc and 9.25vdc while printing. From the power supply I'm getting 12.31vdc.
Re: Hot end questions
Posted: Thu Sep 07, 2017 8:55 am
by geneb
The voltage makes sense at the hot end - it's the PWM you're seeing. The raw output from the power supply seems good though.
It may be a case of the heater cartridge beginning to fail. If it was ME, I wouldn't just change the cartridge - you figure if you're going to tear into the thing, might as well replace the thermistor at the same time and save some hassle.
g.
Re: Hot end questions
Posted: Thu Sep 07, 2017 11:27 am
by barry99705
Cool. Thanks for the second opinion!
Re: Hot end questions
Posted: Thu Sep 07, 2017 12:31 pm
by lightninjay
I had something similar happen, but it turns out my heater cartridge was fine, the Thermistor was failing, and so it kept underreporting temps. This eventually would lead to a Decoupled error being thrown and the hotend shutting off. My stupid mistake would be to turn the printer off, turn it back on, and continue trying to heat the hotend. This cycle would continually heat the cartridge, even though the thermistor was not reporting any temperature change. Ultimately I melted the PEEK section of my hotend and had to swap out for my Prometheus from the stock V2 hotend. Once I discovered it was my thermistor, I replaced it, and I have had stable temps ever since.