Watchdog Reset on all prints, even self test  

RE: Watchdog Reset on all prints, even self test

After re-flashing to 4.0.2, I'm getting a MINTEMP message whenever I attempt a print...

RE: Watchdog Reset on all prints, even self test

Mintemp for bed or hotend?

RE: Watchdog Reset on all prints, even self test

@crawlerin

How can I tell the difference?

RE: Watchdog Reset on all prints, even self test

@bret-w2

Iy says MINTEMP BED if it is for bed.

How cold is the room with printer? Printers don't like 15 degrees Celsius and less, sometimes even 18.

Other things to check is connectors in electronic box if cable hadn't eiggled out, open it up and push connectors to sockets to be sure.

You can cut zipties, unwrap bundle and release thermistor cable, inspect it for visible damage on wires. There's also a possibility thermistor just broke. If you have multimeter, check continuity with it.

Log into your acvount on eshop page, and down in the lower right corner is button to chat with support. They will help you diagnose the problem and arrange replacement.

If I can give small tip, buy extra thermistor and heater cartridge, optionally also nozzle (and maybe MINDA) and keep those as spares. It can help you get up and running faster when things break, or you get blob on hotend, or snap wires accidentally.

BTW I am surprisef now it just gives watchdog error and not even what failed ... didn't they write in 4.0.3 patch notes error messages get improved framework and texts?

RE: Watchdog Reset on all prints, even self test

It's in the room with my Mk3s, and the temp isn't below 18C, especially during the day.

I was planning to re-open the electronics box and just make sure everything was properly connected & seated in the morning. Thanks for the pointers!

The watchdog error is really kind of unhelpful, you're right. I got better messages by downgrading to 4.0.2! Go figure.

RE: Watchdog Reset on all prints, even self test

I just went through this exact same thing. Flashed the new firmware before doing anything else, and then keep getting watchdog resets when trying to run the setup wizard. I also downgraded the firmware, which led to seeing the mintemp error, which led to this GitHub issue: https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/220

I used the workaround of holding a lighter under the nozzle to get it above 15c and I was then able to proceed (with 4.0.3 as well). It’s really pretty silly.

For what it’s worth, my room temperature is about 20c, so it’s not like I’m trying to operate the thing in a refrigerator.

RE: Watchdog Reset on all prints, even self test

From what I read elsewhere, these thermistors are not very accurate reading temperature below 30 degrees, it can vary by as much as 4-5 degrees. It is possible thermometer shows 20,but thermidtor is at 15 which is cutoff temperature for mintemp error. People with printers in cold spaces pre-heat those with hot air gun or hair dryer, once it's printing it maintains the temperature fine.

RE: Watchdog Reset on all prints, even self test

The thermistor doesn't have to be accurate at low temperatures to fix the behavior. Here are four possible options (I'm sure there are more):

1. Lower mintemp to something less likely to trigger in a cold room (my lulzbot uses 0c, and 5c seems to be common on other machines)

2. Use a smarter algorithm for detecting broken thermistors. E.g. on a cold start, turn on the heat briefly and see if the temp goes up, before registering an error.

3. Provide a warning that can be overridden. Even hidden is fine. It could say something like "Low hotend temperature (14c): possible sensor problem. See <...> for details.", and there could be a longer explanation in the manual or web site that discusses the potential risks and tells you how to hold the button down for 3 seconds or something to proceed anyway.

4. Put a mintemp offset setting in a menu somewhere, so people who have this issue can adjust it.

Crashing with a watchdog timer error is a terrible user experience. And Prusa is a premium brand with an "it just works" reputation -- if the official answer is that I have to preheat my machine with a hair dryer every time I use it, it's going in the box and right back to Prague.

RE: Watchdog Reset on all prints, even self test

@masto

You don't need to do it if your temperature is reasonable, but people have their printers in basements and garages during winter. With MINI people had success re-setting the printer with X button as by then temperature has risen a bit. 2 more things:

1. MINI is built for cost and thermistor may be less premium than in MK3 which seems more accurate; 'good enough' but cheaper. You also can't rule out possibility that you have pinched (by ziptie) or broken (by strain) cable, or your thermistor is just malfunctioning.

2. Firmware is still huge WIP right now (they just laid foundation for better error reporting in this release yet error messages are even more confusing?). Things like you suggest may be implemented at one point. Hop onto GitHub and raise an issue there to have devs looks into it.

They are not oblivious to this, apparently working on something: https://twitter.com/josefprusa/status/1230433853728284672  

RE: Watchdog Reset on all prints, even self test

Well, that does make sense, as it is winter here. And it's not like Prusa hasn't established a pattern of learning from early adopters and issuing fixes, so I'm not too upset. If warming the nozzle works (I haven't tried it yet), then we'll do that for now. Stay tuned for a test later today, and thanks for the help!

RE: Watchdog Reset on all prints, even self test

@crawlerin

I'm not trying to make this a big argument. My temperature was reasonable: 70ºF. The manual says "Working temperature range: 18 ºC - 38 ºC". @bret-w2 also says their room was not below 18 ºC. I don't see anything in the manual or build instructions telling me to take a lighter or a hair dryer to the nozzle. Also, the web site says specifically that it has the "same level of reliability as the rest of the Original Prusa family". From this, I am inferring that it's a legitimate problem worth fixing: under correct operating conditions, the system does not operate as intended.

I think this thread and the GitHub issue that I linked provide a good signal that current value of 15 is, if nothing else, causing confusion for users during initial setup. As more printers are delivered, I expect the number of people who run into this snag will go up. Once past the "Uh oh, my machine seems to be broken out of the box" problem and the wasted time troubleshooting the wrong thing, there's a secondary issue. I have never had to warm up my Lulzbot Mini in the 5 years I've had it. If I have to keep a hair dryer around to jump-start the Prusa, every print is going to start with me being disappointed. I don't think anybody wants that.

This is probably coming across more complainy that I'm intending. What I mean to say is just that I think there is value in fixing this, it's not a simple matter of user error or misunderstanding the intended operating conditions of this machine. I believe it probably will be fixed, as it's "just" a matter of tweaking the software. There is already a GitHub issue open on it (I think two of them).

Worst case, I guess I fork the firmware and make it work for me.

RE: Watchdog Reset on all prints, even self test

I also got the Watchdog Message when the display reported temperatures about 15 ° C at the nozzle, which happened because my Mini is in the cellar.

Since I didn't want to use a lighter as suggested by mastro (but thanks a lot for the idea) I just used my fingers to warm the nozzle to 18° and it worked without error message, then I switched on the radiator in the room and no more problems, yay!

RE: Watchdog Reset on all prints, even self test

@masto

I understand your point, I was just saying that MINI apparently has different limit for minimal temperature. I believe handling more extreme conditions is something company is working on, given they had temperature-controlled trailer delivered into their backyard. They know people put their printers into sheds, garages and basements and are working solutions for that.

Also consider that every appliance has "Environmental conditions:" section in their manual, with operational temperatures + humidity. 3D printer being piece of machinery has it too. While microwaves or laptops may work and potentially destroy themselves, Prusa printer not only has minimal working temperature written on paper, it checks it and refuses to operate when these conditions are not met. Within its capabilities, it does not check board or motor temperatures for overheat (yet?) and does not have humidity sensor. But you probably don't call car manufacturer "my car does not start at -19 degrees Celsius, this is unacceptable!" when they write "-5 minimum", but rather work around it to make it warmer first to start.

RE: Watchdog Reset on all prints, even self test

Heating ours with a heat gun took just a few seconds and solved the problem. I'm okay with workarounds until a better solution comes along. This isn't a kitchen appliance... 🙂

RE: Watchdog Reset on all prints, even self test

@crawlerin

Sure, and I would never complain about something that fails when operated outside of its specifications. The manual says the minimum temperature is 18 ºC , and it was in a 21 ºC room. 21 > 18 by a pretty wide gap. I understand it's not very accurate, but the thermistor reading 14 in a 21º room is all the more reason for not having such a high cutoff.

Beyond that, while mintemp is a safety feature, operating the printer in a cold room is not dangerous. It may produce bad quality prints, but that's not why 3D printers have a temperature failsafe: it's not checking to see if it's within environmental operating conditions. It is meant to prevent a condition where the thermistor fails or becomes disconnected, causing the heater to run nonstop until it catches fire. As I described in a previous post, it's pretty easy to work around this whole problem with software. Turning on the heater for just a couple of seconds will immediately cause the temperature to rise. It could ignore the temperature reading for the first 5 seconds after a cold start and most likely nobody would ever hit this problem again, and there would be no increased risk of fire by doing so.

Right now, this problem doesn't affect me. I'm lumping it in the bucket of other things I hope get addressed in a future build (like having a usable network connection). It's possible I'll never even run into this again; maybe my printer was just cold from its long journey from Prague to New York. I've only used it three times so far, but the issue hasn't recurred. I'm not here to demand satisfaction, something just irks me about dismissing a legitimate issue that, by my count, at least 5 people have run into during initial setup, and that's only counting the ones who have found this thread or the GitHub issue and had the motivation to post about it.

I promise I'll let it go now. The printer works great and I should be exploring its capabilities instead of arguing.

RE: Watchdog Reset on all prints, even self test

@masto

It's OK, don't drop the topic if you have something to say or ideas how to improve behavior. I fully agree that such error - especially ambiguity introduced in 4.0.3 - is confusing and I'd start looking into anything else but simple "printer is cold and sensor is inaccurate".

RE: Watchdog Reset on all prints, even self test

RE: Watchdog Reset on all prints, even self test

Here's a video of it. I'm not impressed by this machine at all, I got 2 and have asked to return them. They are simply not market ready and should not have been released yet.

RE: Watchdog Reset on all prints, even self test

@masto

pretty much all the "work out of the box" cheap Chinese printers set mintemp to 5 degrees or 0 degrees and its fine.