RostockMax V2 Calibration Issue Thermistor Fail

[terratian]

Hello Again,
I just received my new replacement lcd, I can now access firmware in the printer. My e3d hotend has an all metal mount. After trying to run a pid routine the test comes back with the result ext0 thermistor fail. Does this mean I need to replace it? I have one that came with the max v2 stock hotend, will this work as a replacement? I changed the configuration.h file value to 8 . When I attempt to run m303 s200 it locks my stepper motors and the lcd reports noz:def and bed:def

I really want to have my printer build done before school starts up again middle of august, any help would be greatly appreciated. Yes, all wiring is correct.

[joe]

lcd reports noz:def and bed:def
. Yes, all wiring is correct.

If it's saying "def" then you probably, most definitely have a wiring issue.

[terratian]

Absolutely nothing has changed since updating the lcd. Everyone keeps defaulting to wiring issues, this has been checked at least twelve times. It only started displaying 'def' since todays pid.

[Mac The Knife]

When "def" is displayed, it is normally a wiring malfunction with one of the thermistors.,,, normally the hotend thermister. It can be either a short or an open, it will still show "def" as a fault.

[terratian]

installed A NEW THERMISTOR tonight. ran all tests in v1 manual updated firmware for thermistor value to 8. endstops pass all tests. pid auto tune...fail. why will this test only pass when the fan is off?

[teoman]

Fan is cooling too much

Not enough heat to heating element.

Try increasing max pid value so system is able to pump more heat.

[geneb]

The /only/ time the firmware will report "def" on the thermistor display is if one of them is broken, shorted, or isn't connected. It has nothing to do with the fan cooling, lack of heat, or PID values.

The simplest way to test the thermistor is with a multi-meter. Disconnect the hot end thermistor leads from the rambo and touch the probes to the bare wires. The meter should read around 100K ohms at a room temperature of 25C. If the value is reasonably close to 100K, then it's likely that the thermistor is ok. If you get no resistance at all, there's likely a short in your thermistor wiring, or the thermistor is defective and is shorted internally. If you get "infinite" resistance on your meter, there's a wiring fault between your test point and the thermistor (open circuit), or a defective thermstor (open internally).

If you get a failed reading while testing at the rambo end, check again at the point where the thermistor is attached to the wiring.

You want to disconnect the wires from the Rambo in order to make sure you're getting a valid reading. The Rambo itself can "contaminate" your testing results.

g.

[terratian]

Fan is cooling too much

Not enough heat to heating element.

Try increasing max pid value so system is able to pump more heat.

max pid is 205, the manual says to lower the value to 128 for a successful reading. What percent on fan should I do the auto tune at and how much more heat?

[terratian]

The /only/ time the firmware will report "def" on the thermistor display is if one of them is broken, shorted, or isn't connected. It has nothing to do with the fan cooling, lack of heat, or PID values.

replacing the thermistor took care of the def reading.
auto tune is still failing.

[Eaglezsoar]

The /only/ time the firmware will report "def" on the thermistor display is if one of them is broken, shorted, or isn't connected. It has nothing to do with the fan cooling, lack of heat, or PID values.

replacing the thermistor took care of the def reading.
auto tune is still failing.

Get some self fusing silicone tape https://www.amazon.com/s/ref=nb_sb_ss_i ... Caps%2C202

Wrap a full layer of the silicone tape around the heat block to act as an insulator so that the fan being on should not effect the temperature of the hot end.

[terratian]

All of the videos I've seen, not one has silicone tape wrapped around the heat block, what is the design flaw here?

[Mac The Knife]

All of the videos I've seen, not one has silicone tape wrapped around the heat block, what is the design flaw here?

https://youtu.be/xvXKt3xDt4E

[geneb]

There is no design flaw.

g.

[joe]

There is no design flaw.

g.

Just us flawed Humans

[Xenocrates]

There's not so much a design flaw as a set of trade-offs and tolerances. Seeme chose to use a design that required minimal machining and used a fan duct that was easily printable (Which give immediate feedback on dimensional tolerances). That means there can be gaps between the fan duct and platform, as well as a gap around the center of the hotend. This can cause some cooling, and there is a voltage tolerance for the fans and power supplies, and both will be unique.

In some cases, the airflow, ambient temp, resistance of the heaters, and other factors can combine to make it hard to reach printing temps, especially with poor PID tunes and aiming for the high end of the envelope of the hotend.

Unless you want to pay far more for the printer and parts, those tolerances have to be accepted. If say, we look at a humble 8-32 3/8 SHCS, a non-class fastener is ~27 cents (surpisingly, with free shiping). If we look at a class A-286 fastener, which will have tighter tolerances, that same thing becomes a 2.50$ screw. The more you are willing to spend, the tighter the tolerances you can get. Some things need those precise parts (Aerospace, especially satellites. I've actually gotten to see in person the backup ball screw for the JWST, and the finish on that is astonishing. I also got to see it's equivalents for everyday use from the same company. And then the cheap chinese versions. In each case, there are applications where it just doesn't make sense to buy the step up)

[terratian]

I also posted my issue with E3d (https://forum.e3d-online.com/index.php? ... post-20172). The moderator seems to think the e3d should not require the silicone tape, which i just picked up at home depot. I am very eager to finally put this issue to rest however it seems to be a problem unique to my particular build. I don't have any more thermistors laying around and hesitate to lower my max temp to 128 just for a successful curve result, the last time i did this i ended up having the thermistor melt and the fan shroud melt. I would like to avoid this. I watched the video of the stock hot-end upgrade, I wish these functional upgrades were integrated into the premium parts I ordered, I would prefer functional parts that i need to pay a little more for the shoddy parts which may or may not work, the thermistor, being an integral component part saftey of the machine should not be prone to an idiot like me.

[terratian]

After wrapping the heating
block and lowering the pid value to 128 I updated my auto tune results and continued to the next step in the calibration manual, this video show the failure. I think I need to order another E3d. https://youtu.be/7FaF9EfrYHA

[Xenocrates]

why is your nozzle so low down? It looks like almost a third of the nozzle length is exposed, which either means you have the heater block threaded too high up the heatbreak (where it necks down should be at the top of the block), which might explain why it has such trouble heating up, the nozzle too low, which would prevent reliable extrusion as there is a gap to fill with molten plastic, or too long a nozzle (Which is rather inexplicable, unless you bought Volcano nozzles with your V6 hotend)

Would you mind taking a picture of the hotend assembly as it stands?

[Polygonhell]

Agreed, the E3D looks to be incorrectly assembled in the video.

[terratian]

This is the best I can do, I screwed it in as much as possible. I have only used the parts the were sent to me with the e3d. Im going to attempt to get it screwed in further. I am considering upgrading to the pt100 sensor. I am not using a volcano.

[Xenocrates]

OK. I see at least two problems there. Firstly, your fan duct is not installed flush, meaning it's directing a large amount of extra air flow onto the heater block. Secondly, your heater block is up too high on the heatbreak. Go ahead and remove the hotend for the moment (Unscrew the lower set of screws right now, leave it on the mount so you have an idea as to clearances).

Then go ahead and get it warm enough to remove your nozzle. Then let it cool down again. lower the heater block until the entire narrow portion of the heatbreak is visible, then warm it back up, and insert your nozzle. Let it warm up the nozzle, and then make sure it's tight. The nozzle should have minimal length visible, and no threads. Then make sure your fan is on and in place properly, with the duct entirely seated. It should look about like so when you're done.
[img]http://cdn3.bigcommerce.com/s-xcbs9s/pr ... 60.png?c=2[/img]

[terratian]

Thank you for the walkthrough. My fan shroud melted previously, that's how it looks now. I ordered the pt100, new bowden for the e3d, and fan shroud today. I'm hoping to resume building my max v2 when the parts arrive. I'm abandoning the thermistor. I will certainly follow the directions when the newest parts arrive.

[Xenocrates]

One thing to be careful about. The PT100 needs an amplifier before it gets to the Rambo (E3D and Filastruder both sell them), and you'll need to make sure you have the right profile. Other than the PT100 profile proper, they really aren't close to right. I can walk you through some of that if you'd like as well.

[Tincho85]

Personally I would do a clean stock e3dv6 install. It's so much easier with the thermistor. Up to 280c +/- is very reliable. I've checked mine with a thermocouple and it's almost perfect. The pt100 is a very different thing that needs tinkering. Please don't take it wrong, but if you can't do a proper install with the thermistor, with the pt100 is going to be so much harder.

[terratian]

One thing to be careful about. The PT100 needs an amplifier before it gets to the Rambo (E3D and Filastruder both sell them), and you'll need to make sure you have the right profile. Other than the PT100 profile proper, they really aren't close to right. I can walk you through some of that if you'd like as well.

I purchased the pt100 from filastruder with the board, I'm hoping all the parts I need are included with the kit. I like the idea of being able to print with more exotic high temp filaments. I rebuilt the e3d last night, will PID autotune again today. I am looking for a photo of the internal of the heatsink, I think something may have melted inside other than filament and Bowden, I am unsure if there were other pieces inside.
I am sure I will need a walkthrough of the pt100, I did a real number on the e3d and those instructions were fairly straightforward.