Printcore unrecognized on insert, requires full power cycle to recover.

[Farbishtwo 0]

Hello, I have a donated UM3 Firmware 5.3.0.  It was heading for the dumpster due to being "broken" and was donated with an AA04 core, a 3dSolex core (I think BB04?) a spare AA04 (new in box) and a CC04 (new in box).

 

I was able to get it working again without much fuss, needed a new screen and some loving (back story available if it becomes relevant).

 

The AA core that came with the printer broke after a few prints (the clear plastic light guide, that also retains the spring broke, upon removal while cleaning)  I very much regret not saving it for parts...

installed the second AA core and had a few good hours of printing (~5 hours according to the printcore data).

Unfortunately, I failed to apply my bed adhesion on a print, walked away from an "ok" first layer for "just a moment" (which turned into an hour), and came back to the head fully encased in a large blob of plastic.  (I also don't have the bit of silicone that is supposed to prevent this from getting up into the cores) 100% my bad.

 

Aborted the print and did my best to save the printcore, but damaged the PT100 wire in the process.  I've managed to get it back to working but it's in rough shape and I'm not 100% on the security of the PT100 to PCB connection (I will be trying to request/purchase a new one (or maybe just a whole new printcore) from 3dsolex in the coming days).

 

Since I had the CC04, I decided to install it, especially owing to my insecurities about the "bodged" AA04, and discovered that I couldn't use it.  Upon insertion the printer says Unrecognized eeprom data in slot 0 , goes into an error state, and there is a "clunk" noise.  Not the click of an inserted printcore, the kind of clunk you hear when a machine loses power.

the printer is still "on" but is stuck on the error screen (ssh works, commands work (e.g., I can reprogram the cores, read files, change the LEDs), scroll wheel moves up / down the error screen, button beeps,etc.).

 

Much searching and reading led me to gr5's post and site about reprogramming cores.  Decided I didn't have anything to lose so I followed the directions. 

I can see from Dev mode that the core does reprogram (output from select printer printer/head/0/slot/0 --> list), but removing and reinserting the core has no affect on the error state.  If I remove the core and power cycle everything works fine.  Reinserting the reprogrammed core leads to the error and "clunk" described above.

 

I have read posts of people using CC04 so I'm not sure where to go from here.

Happy to post any logs or screen grabs or what ever, just wasn't sure what would be helpful.

 

Any thoughts?

 

ps, I'm running PLA and ABS at the moment, not trying to run anything fancy or super abrasive (yet).  I recognize and appreciate the OEM UM3 extruders are not suited for abrasives and will cross that bridge if / when I get there.  At the moment, I'm just trying to get the printer to run again (without using the "repaired" AA04 core).

 

[gr5 2,265]

The clunk is almost always caused by a bad temperature reading so I'd check the resistance across the 2 side gold leads that go to the temp sensor.  At room temp a pt100 should read roughly 109 ohms.

 

The message may "say something different" but it might be that there are 2 messages?  I don't know but that clunk - I only hear that with bad pt100 readings.

[CarloK2 9]

Could you mail me the log files? Perhaps I can find something.
Use this procedure:
- Go into the maintenance menu and select the option to write all the log files from the UM3 onto the USB flash drive.
- Zip those files

- Email the zip file to me: click on my avatar and select the 'message' option on top of the page

 

One note about the CC-core in the UM3, the UM3 feeders are not hardened and will wear out with printing just one filament spool. For this reason, Cura wil not allow you to print all materials in this core. You might consider to re-program the CC core as an AA core. which gives you more flexibility.

Edited November 3 by CarloK2

[Farbishtwo 0]

2 hours ago, gr5 said:

The clunk is almost always caused by a bad temperature reading so I'd check the resistance across the 2 side gold leads that go to the temp sensor.  At room temp a pt100 should read roughly 109 ohms.

 

The message may "say something different" but it might be that there are 2 messages?  I don't know but that clunk - I only hear that with bad pt100 readings.

I get between 107 and 108 it bounces a bit, but I think that might be my unsteady hands.  Just for giggles I did the heater core too, it was 24.

I've attached pics of the message I get when I insert the core.
Please let me know if I can provide anything else

[Farbishtwo 0]

1 hour ago, CarloK2 said:

Could you mail me the log files? Perhaps I can find something.
Use this procedure:
- Go into the maintenance menu and select the option to write all the log files from the UM3 onto the USB flash drive.
- Zip those files

- Email the zip file to me: click on my avatar and select the 'message' option on top of the page

 

One note about the CC-core in the UM3, the UM3 feeders are not hardened and will wear out with printing just one filament spool. For this reason, Cura wil not allow you to print all materials in this core. You might consider to re-program the CC core as an AA core. which gives you more flexibility.

I don't seem to be able to attach anything to the message that pops up when I click your avatar. 

Is it a bad idea (or against the rules) to drop the zip for the logs here in the chain?

Perhaps I've not gotten out of my 'new user probationary period'

 

failing that I can put them up on drop of something?

 

Appreciate the help either way!

[gr5 2,265]

You can probalby just post the zip file in this thread if you want.  Or post it somewhere online (such as google drive) and provide us with a link.

[gr5 2,265]

@Farbishtwo you are very lucky you caught the eye of carlok2 as carlo doesn't post much here and he is a firmware engineer who used to work for Ultimaker (maybe still does).

[gr5 2,265]

5 hours ago, Farbishtwo said:

I get between 107 and 108 it bounces a bit, but I think that might be my unsteady hands.  Just for giggles I did the heater core too, it was 24.

Well then it's not that.  107/108 is fine - you are just in a cooler room than mine.  Maybe it's programmed up wrong?  I think my instructions only alter the type: for example from BB 0.4 to AA 0.4.  I don't think it alters all the other stuff programmed onto a printcore.  Could you dump out the whole core?  Try these commands.  This also shows the result for an AA 0.8 core from many years ago.  Do P0,P1,P2,P3

 

Your values will vary - particularly if anything is different the checksum at the end will be different.  So don't worry about that.  Also this contains things like hours hot, highest temperature, and other things that are different for every core.

 

AA 0.8 CORE:
============
(Cmd) sendgcode M150 T0 P0
DATA: 0x04556c74696d616b657200000000414120302e38000000000000000000000072
ok N251 P15
(Cmd) sendgcode M150 T0 P1
DATA: 0x203495e046030047e00000000000000000000000000000000000000000000019
ok N15 P15
(Cmd) sendgcode M150 T0 P2
DATA: 0x506c9f0de3aa4bd4b2d223e2425b1aa900069200024b36000000000000000083
 

[Farbishtwo 0]

9 hours ago, gr5 said:

You can probalby just post the zip file in this thread if you want.  Or post it somewhere online (such as google drive) and provide us with a link.

I've attached it to this post (couldn't post anymore last night as everything was hidden and awaiting mod approval) still in newbie probation I assume.

 

 

9 hours ago, gr5 said:

@Farbishtwo you are very lucky you caught the eye of carlok2 as carlo doesn't post much here and he is a firmware engineer who used to work for Ultimaker (maybe still does).

I was worried I wouldn't catch anyone's eye, but I'm incredibly happy that I did.  If I'm honest, I only created the account to post because your activity was very recent given the lack of other posts on the matter, I had about given up. 

I've also enjoyed all the reading I've now done on the internals of the system.  It's an interesting reprieve from my usual adventures in Klipper.

 

6 hours ago, gr5 said:

Well then it's not that.  107/108 is fine - you are just in a cooler room than mine.  Maybe it's programmed up wrong?  I think my instructions only alter the type: for example from BB 0.4 to AA 0.4.  I don't think it alters all the other stuff programmed onto a printcore.  Could you dump out the whole core?  Try these commands.  This also shows the result for an AA 0.8 core from many years ago.  Do P0,P1,P2,P3

 

Your values will vary - particularly if anything is different the checksum at the end will be different.  So don't worry about that.  Also this contains things like hours hot, highest temperature, and other things that are different for every core.

 

AA 0.8 CORE:
============
(Cmd) sendgcode M150 T0 P0
DATA: 0x04556c74696d616b657200000000414120302e38000000000000000000000072
ok N251 P15
(Cmd) sendgcode M150 T0 P1
DATA: 0x203495e046030047e00000000000000000000000000000000000000000000019
ok N15 P15
(Cmd) sendgcode M150 T0 P2
DATA: 0x506c9f0de3aa4bd4b2d223e2425b1aa900069200024b36000000000000000083
 

Here are the results of the commands requested:

(Cmd) sendgcode M150 T1 P0
DATA: 0x0000000000000000780000000000414120302e34000000000000000000000000

o760FE7
(Cmd) sendgcode M150 T1 P1
DATA: 0x0000000000000047e00000000000000000000000000000000000000000000091

o990F64
(Cmd) sendgcode M150 T1 P2
DATA: 0x0000000000000000000000000000000000000000000000000000000000000000

oAB0F6D
(Cmd) sendgcode M150 T1 P3
DATA: 0x0000000000000000000000000000000000000000000000000000000000000000

oBF0FFC

 

Additionally, not sure it's useful, but here is the output of the command I was using to verify that it had written to the core (not even sure this is verification as it may just be text in a file and have no relevance to what the machine is looking at when reading the core upon insertion).  In comparing it to the other cores I have the only differences I can't explain away (e.g., difference in last material guid, material extruded, and max temperature) are the angle, flat_size, and hot_zone_size.

 

(Cmd) list
abrasive_resistant = 0
angle = 0
current_temperature = 21.3
filament_size = 2.85
flat_size = 0.0
hardware_revision = 0
hot_zone_size = 0.0
hotend_cartridge_id = AA 0.4
insert_type = teflon
interaction_required = 0
is_enabled = 0
is_present = 1
is_primed = 0
is_retracted_for_hotend_change = 1
last_material_guid = 00000000-0000-0000-0000-000000000000
manufacturer_id = x
material_extruded = 0
material_guid = 60636bb4-518f-42e7-8237-fe77b194ebe0
material_guid_source = USER
max_exp_temperature = 0
max_power = 75
max_target_temperature = 350.0
maximum_temperature = 0
nominal_resistance = 23.0
nozzle_size = 0.0
pid_Kd = 40.0
pid_Kff = 0.57
pid_Ki = 0.2
pid_Ki_max = 100
pid_Kp = 9.0
pid_Kpcf = 0.06
pid_functional_range = 25.0
pre_tune_target_temperature = 0.0
programming_state =
serial_number = 84c2243f0000
target_temperature = 0.0
temperature_measurement_gain_factor = 0.985
temperature_measurement_gain_offset = 0.75
time_spend_hot = 0
tune_offset_temperature = 0.0
voltage = 24.0
x_offset =
y_offset =
z_height =
z_offset =
(Cmd)

 

Just for full clarity, I've tried the core in both slots, tried programming it in both slots, cleaned the core and printhead contacts with 99% IPA, tried different variations (e.g., AA0.25, BB 0.6), looked around for ways to duplicate the info from core 1 to core 2 (e.g., copy the manufacturer_id, or angle, etc.), but couldn't find documentation and decided to ask for help before tossing random sendgcode commands around, thought about pulling the PCB from the "repaired" printcore (decided that would be an absolute last resort if my repairs cease to hold and I can't get a replacement PT100 from 3D Solex).

 

Happy to experiment as there is, in theory, nothing to lose.

Thank you, once again, for the help. 

requested Logs.log.zip

[gr5 2,265]

Yikes - this core was never programmed in the first place as far as I can tell.  Is this an ultimaker core or a 3d solex core.  Email me at "thegr5store" at "gmail.com" if this is for a 3dsolex core.  I'll give you the UM commands in a few minutes...

 

[gr5 2,265]

This is from my old AA 0.4 that I read many years ago but you can then set it to another type after you send all these.  Really it's just the A8 and A16 ones that set what type of nozzle.  Some of that other data is how long the core has been hot for (for example) so you are going to get some values from my core from like 7 years ago.  I think it might be the  A80 one.  If this all works and you want to reset the "odometer" try setting the A80 one to all zeros after the D.  Anyway much of the data below is critical for the core to be accepted even though not much is used.

 

Don't use this for a 3dsolex as that has different data.  It has PID data specifically for 3dsolex cores which have higher wattage heaters in their cores.  I have that info as well somewhere.  But you measured the heater at 24 ohms which implies 24v*24v/24 ohms or 24 watts so you must have an ultimaker core.

 

Each time you program a core, you have to pop it out and pop it in for it to be re-read.  But of course if your printer is locked up you have to reboot the printer anyway.

 

 

sendgcode M151 T0 A0 D04556c74696d616b
sendgcode M151 T0 A8 D6572000000004141
sendgcode M151 T0 A16 D20302e3400000000
sendgcode M151 T0 A24 D00000000000000e7
sendgcode M151 T0 A32 D103495e046030000
sendgcode M151 T0 A40 D0000000000000000
sendgcode M151 T0 A48 D0000000000000000
sendgcode M151 T0 A56 D00000000000000C9
sendgcode M151 T0 A64 D506c9f0de3aa4bd4
sendgcode M151 T0 A72 Db2d223e2425b1aa9
sendgcode M151 T0 A80 D00004b00004134c0
sendgcode M151 T0 A88 D00000000000000b8

[gr5 2,265]

By the way, I've heard the "clunk" sound before when, for example, I remove a core while it's still > 60C.  Many times.  On both my UM3 and my S5.  I never really thought what the sound was.  I think there is a 24v relay that is opened possibly (there's on in the UM2) which stops 24v to all heaters and servos but that has a very quiet click.  Not too hard to hear but it's not a thunk/clunk.  

 

Instead I think the clunk is when the printer disables the servo drivers which releases the Z axis servo and it moves (typically) a half step suddenly.  And also on some printers the bed will actually fall to the bottom which is typically only 1 cm or so.  So the most noticeable thing might the sound of the bed either hitting the bottom or at least dropping a tiny bit.

[Farbishtwo 0]

9 hours ago, gr5 said:

Yikes - this core was never programmed in the first place as far as I can tell.  Is this an ultimaker core or a 3d solex core.  Email me at "thegr5store" at "gmail.com" if this is for a 3dsolex core.  I'll give you the UM commands in a few minutes...

 

I'm moderately certain this was purchased from Ultimaker (person who donated the printer wasn't sure, but said they only ever ordered from Ultimaker and the one core from 3D Solex).  However, the core is branded Ultimaker and came from an Ultimaker branded box (pictures attached).

 

9 hours ago, gr5 said:

This is from my old AA 0.4 that I read many years ago but you can then set it to another type after you send all these.  Really it's just the A8 and A16 ones that set what type of nozzle.  Some of that other data is how long the core has been hot for (for example) so you are going to get some values from my core from like 7 years ago.  I think it might be the  A80 one.  If this all works and you want to reset the "odometer" try setting the A80 one to all zeros after the D.  Anyway much of the data below is critical for the core to be accepted even though not much is used.

 

Don't use this for a 3dsolex as that has different data.  It has PID data specifically for 3dsolex cores which have higher wattage heaters in their cores.  I have that info as well somewhere.  But you measured the heater at 24 ohms which implies 24v*24v/24 ohms or 24 watts so you must have an ultimaker core.

 

Each time you program a core, you have to pop it out and pop it in for it to be re-read.  But of course if your printer is locked up you have to reboot the printer anyway.

 

 

sendgcode M151 T0 A0 D04556c74696d616b
sendgcode M151 T0 A8 D6572000000004141
sendgcode M151 T0 A16 D20302e3400000000
sendgcode M151 T0 A24 D00000000000000e7
sendgcode M151 T0 A32 D103495e046030000
sendgcode M151 T0 A40 D0000000000000000
sendgcode M151 T0 A48 D0000000000000000
sendgcode M151 T0 A56 D00000000000000C9
sendgcode M151 T0 A64 D506c9f0de3aa4bd4
sendgcode M151 T0 A72 Db2d223e2425b1aa9
sendgcode M151 T0 A80 D00004b00004134c0
sendgcode M151 T0 A88 D00000000000000b8

Thank you, I'll be trying these when I get home later tonight.  Incidentally, my apologies for the duration between my replies, today was indeed a day 🙄. 

 

Maybe you'll answer by the time I'm home, and I'm fairly sure I know the answer.  Just to be on the safe side based on how you worded your reply.  Programming the core is sending all of the lines listed (A0 through A88, one at a time) and THEN removing / inserting the core, yes?  I can read the above as send a line, cycle, repeat.  I don't think that's what you're saying, but maybe I'm being obtuse.  Additionally, a lifetime of reading / writing SOPs has made me a bit pedantic (also, I'd rather ask an idiotic question than find out I was wrong all along).

 

9 hours ago, gr5 said:

By the way, I've heard the "clunk" sound before when, for example, I remove a core while it's still > 60C.  Many times.  On both my UM3 and my S5.  I never really thought what the sound was.  I think there is a 24v relay that is opened possibly (there's on in the UM2) which stops 24v to all heaters and servos but that has a very quiet click.  Not too hard to hear but it's not a thunk/clunk.  

 

Instead I think the clunk is when the printer disables the servo drivers which releases the Z axis servo and it moves (typically) a half step suddenly.  And also on some printers the bed will actually fall to the bottom which is typically only 1 cm or so.  So the most noticeable thing might the sound of the bed either hitting the bottom or at least dropping a tiny bit.

I think the 24v relay (if there is one, I've not looked), is the likely source of the noise.  The printer is in a room with poor acoustics so it may be amplifying the clunk.  It's definitely much louder than any other sound the printer makes (with the exception of fast accelerations during a print (those A4988, I think).  I was only using it as another symptom to help with diagnosis.

 

Anyway, will update later tonight, maybe tomorrow morning with the results form re-programming the core.

 

PS.  I had reached the conclusion that the 3dSolex cores were slightly different based on my comparisons of the two and the differing PID values, thank you for confirming that.

Are you still a re-seller of 3dSolex items, I had thought that I found a link somewhere but the led to a site with no 3d Solex merchandise.

 

Update to follow

 

[gr5 2,265]

8 minutes ago, Farbishtwo said:

Programming the core is sending all of the lines listed (A0 through A88, one at a time) and THEN removing / inserting the core, yes? 

Yes.  But you will probably have to reboot the printer if it is locked up already so then no need to take it out and put it in.  Once it is locked up with a "serious" error message there is no remedy other than power cycle.

 

That's an Ultimaker core.  3dsolex doesn't say ultimaker on their print cores (they say 3dsolex).  Plus their boards aren't white - they are red (usually - there may be some black ones also but those are very unusual).

 

I used to sell parts for Ultimaker printers including 3dsolex parts but I have been slowly shutting down the store and recently I took the store offline because of some crazy activity on the store and I was down to maybe 2 sales per year.  I have some parts but not enough to put together a 3dsolex core.  I have some stuff that no one seems to want like (possibly for example) a 2.5mm (huge!) print core with ruby nozzle.  Obscure stuff that no one wants.

[Farbishtwo 0]

Brief moment of panic while the printer (seemingly, though I'm sure I imagined it) took a mini eternity to boot following programming, and SUCCESS!

 

Thank you for everything.  A few questions if you don't mind?  Did you gain your knowledge of programming the cores through trial and error, or is there a resource that you can share / point me at (curiosity mostly, and it's the sort of thing I like to read / watch in my spare time).  Is there a way to see what type of core this 3dSolex is?  It was originally programmed as a BB04, but I don't see BB option on their site (may just be very old too).  The heat break is red and the nozzle appears to say 40 on it, but it's got quite a bit of char / carbon on it so not 100% sure.  From what I've read, I can try to use it as a "AA" core, but that it would ooze, but think it'll stay in slot 2 as a backup.

 

I had asked about re-selling to see if you could sell a PT100, but I'll reach out to 3dSolex.

 

Once again, a huge thank you for your time and much respect to your substantial depth of knowledge here.

[gr5 2,265]

The data is documented in the source code which is in python and sitting in plain sight on your printer.  I just did some grep searching until I found it.

 

I know how this all works because I helped Carl, the owner of 3dsolex, with many technical details and I was his main seller in USA for maybe 10 years.  Long before the S5 was released.  From back when the UM2 was the hot new printer.  I'm the one who came up with the best PID values for each of his printcore heaters by tweaking the values for hours.

 

The nozzles are changeable on the 3dsolex.  There is no difference between the AA 0.4 and BB 0.4 3dsolex core or nozzle.  So just rename it to an AA 0.4.  They work just fine but the big advantage of 3dsolex is quickly changing nozzles and he has like 10 different nozzle sizes from 0.1mm to 2.5mm.  Including ruby nozzles for abrasive filaments.  You can also change a nozzle quickly if it's clogged and deal with the clog when things settle down and the printer will be idle for an hour.

 

Don't try to change the nozzle without the nozzle changer tool as it's trivially easy to destroy the heat break which is steel but only about as thick as a sheet of paper.  The thin spot is kind of hidden unless you squeeze the lever on the print core and look in the gap.  If you have the finger strength to twist a cigarette into two pieces you can also easily torque the printcore nozzle hard enough to snap the heat break using even the smallest of wrenches.

 

[Farbishtwo 0]

10 hours ago, gr5 said:

The data is documented in the source code which is in python and sitting in plain sight on your printer.  I just did some grep searching until I found it.

 

Looks like I have some brushing up to do on my linux command line, it's been a nearly a decade.

 

10 hours ago, gr5 said:

I know how this all works because I helped Carl, the owner of 3dsolex, with many technical details and I was his main seller in USA for maybe 10 years.  Long before the S5 was released.  From back when the UM2 was the hot new printer.  I'm the one who came up with the best PID values for each of his printcore heaters by tweaking the values for hours.

That is quite the CV.  Thank you for that time and effort, I'm sure I'll appreciate it even more once I order my new core.

 

10 hours ago, gr5 said:

The nozzles are changeable on the 3dsolex.  There is no difference between the AA 0.4 and BB 0.4 3dsolex core or nozzle.  So just rename it to an AA 0.4.  They work just fine but the big advantage of 3dsolex is quickly changing nozzles and he has like 10 different nozzle sizes from 0.1mm to 2.5mm.  Including ruby nozzles for abrasive filaments.  You can also change a nozzle quickly if it's clogged and deal with the clog when things settle down and the printer will be idle for an hour.

I had seen the nozzle change part, and thought it was pretty great idea.  Unfortunately, I do not have a nozzle change tool.  I will inquire about it when I order a new core.

 

10 hours ago, gr5 said:

Don't try to change the nozzle without the nozzle changer tool as it's trivially easy to destroy the heat break which is steel but only about as thick as a sheet of paper.  The thin spot is kind of hidden unless you squeeze the lever on the print core and look in the gap.  If you have the finger strength to twist a cigarette into two pieces you can also easily torque the printcore nozzle hard enough to snap the heat break using even the smallest of wrenches.

I have watched your (I think) video on disassembling a printcore (took "thick as a sheet of paper" to make the connection in my mind).  Is the nozzle change tool the socket driver 3dprinted torque wrench that you're using in that and the "gr5 pull" video, or something else entirely?  Either way, I don't plan on doing any disassembly of any core till I have a spare.  Probably practice on the AA disinterred from the ABS blob that started me down this path.

 

At any rate, You've been most helpful and I am incredibly grateful.  I have a better understanding to the following and devotion these machines have now, and look forward to learning it's secrets and tricks (like how to get stuff to stick to the bed better so I don't break expensive printcores 😄).

 

Best wishes!

F

[gr5 2,265]

Every printcore ordered from 3dsolex comes with a nozzle changer tool.  It's the 3d printed plastic part plus one of these wrenches (that slides in) plus instruction sheet.  plastic part and wrenches shown in single photo on this page:

https://3dsolex.com/product/printcore-s5-engineer-350/

 

You can use a crescent wrench instead and some knowledge.  3dsolex doesn't ship torque wrenches - just use the tiny wrench supplied for the hex nozzle and you won't break the nozzle itself.  Those nozzle are tough but people who use full sized socket wrenches often destroy the nozzle if there is some melted filament gripping the threads.  You need to heat the nozzle if it doesn't unscrew easily.  And then heat it again.  Anyway this is all explained on the instructions.

[CarloK2 9]

Glad to see you guys figured out a solution.

Just for fun I looked at the log files (thanks for posting them), and there is an error for an unknown hotend like you guys already figured out.

 

My guess is that this error is not correctly handled by the printer, we always had correct programmed printcores to test with. ☺️

The printer seems to be stuck in a loop trying to open a screen for a non-existing printcore type.

 

The clunk sound, I suspect this is for the motor of the z-axis being released and the buildplate dropping a few milimeters. Many printers have some friction here, but you are lucky to have a well aligned printer here.

[Farbishtwo 0]

7 hours ago, gr5 said:

You can use a crescent wrench instead and some knowledge.  3dsolex doesn't ship torque wrenches - just use the tiny wrench supplied for the hex nozzle and you won't break the nozzle itself.  Those nozzle are tough but people who use full sized socket wrenches often destroy the nozzle if there is some melted filament gripping the threads.  You need to heat the nozzle if it doesn't unscrew easily.  And then heat it again.  Anyway this is all explained on the instructions.

I have my fair share of experience in stripping threads on nozzles from other printers, I've learned to be gentle an apply heat if / when necessary. 

 

1 hour ago, CarloK2 said:

Glad to see you guys figured out a solution.

Just for fun I looked at the log files (thanks for posting them), and there is an error for an unknown hotend like you guys already figured out.

 

My guess is that this error is not correctly handled by the printer, we always had correct programmed printcores to test with. ☺️

The printer seems to be stuck in a loop trying to open a screen for a non-existing printcore type.

 

The clunk sound, I suspect this is for the motor of the z-axis being released and the buildplate dropping a few milimeters. Many printers have some friction here, but you are lucky to have a well aligned printer here.

I'm very curious how I got, what appeared to be, a blank core.  I'm not complaining, not by any means, I learned a great deal here and got to stretch my brain a bit, so on the whole a positive experience.

 

Thank you for going through the logs and confirming what we'd found (any confirmation is good).

I hesitate to say it was the bed making the noise as the bed was always at rest at the bottom any time I inserted or removed the core.  I had lowered it all the way when I had the flood to get at the nozzle while it was still attached so I could keep it at 260 while I used tweezers to pick out the ABS.  It is very smooth though, If I give it a tap while it's up and the motor is disengaged it will lower itself down to the floor.

(I did put lots of effort into making it clean, square, tight (screws, fasteners, etc.) and re-lubing everything when I was saving it from the trash though).

 

Thanks to both of you again!