Hi guys, I’m happy to re-start using my TAZ 2.0 after a while.
BUT… I’m having a problem. I haven’t used the machine for around 1.5 years. I have used it a few days after buying it and it worked fine. Now I can’t even reach the desired bed temperature. After some minutes the connection between the TAZ and PC (both with latest PRONTERFACE and CURA) is lost, and it gives a timeout/write fail error message. Here it’swhat happens on Pronterface after Setting bed temperature to 85 degrees Celsius. Some minutes later (eg 20 minutes later, but it varies) when temperature reached 81 degrees Celsius, but other times it happens with temp reaches other values such as 76)
[ERROR] Can’t write to printer (disconnected?) (SerialException): Write timeout
[ERROR] Can’t write to printer (disconnected?) (SerialException): Write timeout
[ERROR] Can’t write to printer (disconnected?) (SerialException): Write timeout
[ERROR] Can’t write to printer (disconnected?) (SerialException): Write timeout
[ERROR] Disconnecting after 4 failed writes.
Disconnected.
[ERROR] Disconnecting after 4 failed writes.
Disconnected.
[ERROR] Disconnecting after 4 failed writes.
Disconnected.
This error/lost USB connection seems to happen only when attempting to heat up: The connection can be OK for example during 15-20 minutes if I’m doing nothing (ie no heating attempted). Actually, the connection seems to be lost exactly when the fan starts
I have tried with different USB ports of my PC and 2 different cables.
At some point I thought it was related to the RAMBo ESD Jumper, but after following instructions (*) I think I do not need to fix it, because my board says “RAMBO rev1.1b” and the instructions say that “The jumper cable will only need to be installed on RAMBo electronics version 1.2(a-f). If you have a RAMBo v1.0 or v1.1, this fix is not needed.”
So I don’t really know what to do, can you help me?
Do you think I should go ahead and try the jumper fix anyway?
Check your USB port power settings under control panel:power options. Under the advanced options for whicher power plan you have selected (I reccommend High performance) ensure that USB selective suspend is set to “disable” and under PCI settings "Link State power management is set to “off”. This should prevent windows from powering off the port when it thinks nothing is happening to it, such as when a printer is heating up and no data is being sent to it.
If thats not it, you could have a partially cooked fuse in the control board on the printer itself perhaps.
Same PC you used before? Same operating system? Try un plugging and re plugging the connections you would be surprised at the amount of crud that can build up over time.
Well, coming back to the issue. Thanks for the comments. I’m not longer sure if it’s a USB problem. Helpdesk at Lulzbot instructed me to try printing directly from the SD card and so I did. But unfortunately it doesn’t work, even with the USB disconnected.
So I copied the STL file into the SD card, unplugged the USB and set the bed and extruder temperature using only the LCD (thanks piercet!!![*]). The temperature starts rising but at some point (at a random temperature, but always above 60C) the printer seems to reset itself: the LCD shuts down for a second and restarts showing the information as if it had been just turned on.
Doesn’t it sound like a current-related issue? I’m using a cable extension, maybe the ground is not properly connected in my extension or something? Doesn’t it sound like a static charges issue? My region is VERY dry and windy, and quite often we face problems with some electronics due to static not fully “discharging” to ground.
As I said in my first post, I’m tempted to try the jumper fix anyway (my TAZ included a spare jumper with a small message that I may need to use it because some TAZ models were defective or something)… but in the instructions it says that I don’t need it: https://ohai-kit.alephobjects.com/project/rambo_esd_jumper_install/
I’ve tried the USB port power settings and it doesn’t seem to make a difference. I’m using the same PC and same operating system (Win7pro64bits, although with lots of updates since the time I bought the TAZ). It was working just fine when I bought it :’(
It sounds like your power supply may be shutting down under load. You could watch the little green LED inside the power supply and see if it blinks off when the printer resets. If it blinks your supply shut down for a second which will cause a printer restart.
Is the case fan on your TAZ electronics enclosure turning on at all? If not, is there anything caught in it? If you are unsure, you can try removing the side cover and directing a small house fan at the board. Only other thing I can think of that would do that would be a loose wire or a short of some sort. It’s possible you have a mostly cooked fuse that is still connecting, but lifting when the printer gets a bit warmer. It could also be a power supply going bad, or one with a failing fan. Is the power supply out in the open where it can get good airflow?
The fact that it seems to always happen when the bed crests 60c makes me think it might be a fuse or a short issue. Does it still reset if you only heat the bed and leave the extruder cold? Also check all the heated bed cables and connections, possibly a loose pin?
Do you know if you have the 24 volt bed, or the 12 volt one? if the power supply says it is 12 volts, you probably have the 12 volt one. If you are on 12 volts, it might be worth the money to upgrade to a 24 volt power supply and bed (though firmware changes would be required) https://ohai-kit.alephobjects.com/project/taz_12v_to_24v/
OK I have tried and it keeps restarting. However this time I observed as carefully as I could and noticed the that when the TAZ restarts, it does in a given sequence (pay attention to the red LED inside the board case and the cooler fan of the power supply):
When I turn on TAZ, the red LED is off. After a while it lights up (no blinking).
As the temperature is above ca. 60C, the red LED starts blinking.
**3. the fan in the power supply starts
the TAZ restarts.**
The sequence repeats every time, the only thing that changes is the exact temperature at which it restarts.
kmanley57: The green led in the power supply does not blink. Does this discard a power supply failure?
So, if I understand the board seems to be the culprit by now, right? Is it reasonable to think that the board is shutting down for some reason when there is “too much” current being drawn (that is what I guess because it only happens when I’m raising the temperature).
If the problem is related to static charge/proper ground of my electrical instalation, I could maybe connect a wire from the aluminum case of the board in the TAZ to some ground-ish in my home like the aluminum windows frames?
Any ideas? At this point the problem seems to be electronic/electrical right? I don’t know much about electronics but I have a tester if you need me to check something in particular… I can’t think of much more than that
I don’t think it’s of any help, but just in case you want to know, I tried again with and without USB connection (using CURA) and I get the following. Error log from CURA:
Send: M105 T0
Recv: ok T:23.7 /0.0 B:75.1 /85.0 @:0 B@:121
Send: M105 T0
Serial timeout while writing to serial port, trying again.
Unexpected error while writing serial port: SerialTimeoutException: ‘Write timeout’ @ machineCom.py:_sendCommand:568
Changing monitoring state from ‘Operational’ to 'Error: SerialTimeoutException: ‘Write time…’
Connection closed, closing down monitor
If it resets right after the fan in the power supply restarts, that would actually indicate a power supply failure to me. The fan in the power supply is independant from the TAZ. the Taz gets power from the power supply, but it doesn’t send any data back to the power supply itself. The fan kicks in on the power supply only when it’s own internal thermometer says its getting too hot. A power supply is also a likely failure point.
It could theoretically be the grounding issue, but if you have your TAZ disconnected from USB entirely, that rambo board short issue probably isn’t it unless I misundersood what was causing that particular issue.
There may also be a fuse in the power supply itself. I can’t remember if there is one there on a Taz, or if that was another printer.
Hi guys, I did some new tests (see below) but fist let me answer some questions:
Is the case fan on your TAZ electronics enclosure turning on at all? YES
“…a loose wire or a short of some sort. It’s possible you have a mostly cooked fuse that is still connecting, but lifting when the printer gets a bit warmer”. I checked and it doesn’t look like, to my (non-trained eye anyway!)
Is the power supply out in the open where it can get good airflow? Yes, totally
Does it still reset if you only heat the bed and leave the extruder cold? YES
Also check all the heated bed cables and connections, possibly a loose pin? YES
Do you know if you have the 24 volt bed, or the 12 volt one? I don’t know, it doesn’t say anything on it. It just says the following code: KT-PR0012-5387 (or maybe those are “O” and not zeroes, KT-PROO12-5387)
That’s probably the 12 volt power supply. Which means you may want to consider upgrading anyways. If you upgraded the bed and the power supply, you could also pick up a set of the Motion pieces required to get to Taz 4 spec. http://i-t-w.com/hardware/ Specifically the Taz 4 X axis end plates, Leadscrews and Nuts, then you would just write the Taz 4 firmware to it. You could then add a hexagon hotend and get to Taz 5 spec. Lots of work, and some expense, but less than buying a new Taz 5 since you already have the frame.
So, this is interesting. I opened the power supply and checked for any “abnormalities” (broken things, un-soldered cables or pins, loose connections, etc.). Disclaimer: since I’m not an expert, I could have only detected very evident things.
Everything looked fine to me. The fan, the rest of the things, cables, board, nothing burn, etc. at least nothing spectacularly burn
There were a couple of components touching each other but I assume that is not a problem (eg some capacitors or things like that) but I straightened them just so they look right. After inspecting, I closed the case again.
OK what follows is “interesting”. I tried again, 3 times with different setups (always completely disconnected from the USB cable):
a wire connecting the case of the board to the case of the power supply
a wire connecting the case of the power supply to the aluminum frame of house window
Always the same result: temperature raised and did not reach set values (it reaches a maximum between 60 and eg 78C) but the machine did not restart (I didn’t try 1 and 2 combined though)
More crazy: I tried just now, without any cable and I get the same: no optimal temperature but no more restarting.
So, maybe I touched something in the power supply? or the “ground” cable I used changed something?
Just for curiosity I just tried again without any “ground” wire (eg. unlike options 1 and 2), and connected to my USB. The same: the temperature reaches a maximum value (less than 80 this time) and starts going down, but the USB connection is not lost.
Should I try the jumper option even if the instructions say I don’t need to do it because I have RAMBo 1.1?
First off, be very careful when opening a power supply. There are very large capacitors in there that will do very bad things to you if you touch them. If it’s not resetting anymore, you may have fixed an internal fault, though it may be temporary.
Which temperature isn’t reaching what it is set at? The extruder, or the bed? If its the extruder, you may need to replace the heater or the thermistor. If its the heated bed, you may need to replace the bed thermistor, or replace the bed.
If your heat bed is not reaching the set temperature. Try placing several sheets(around 5) of paper on top of the bed to reduce the thermal loss to the air and see if it can now reach the set temp. If so then you probably lost a heating wire or two in the heat bed. Which means you need a new bed.
piercet, thanks for the advice, I let the power supply alone (disconnected from both the printer and the electricity) for a few hours before opening.
The extruder reaches 230 with no problem. The bed does not reach the set temperature (85C in my case, I’m trying to print with ABS).
Is there something I could look for in the bed itself? Any test I could do to see if the problem is in the bed (versus the power supply)?
kmanley57: “If so then you probably lost a heating wire or two in the heat bed. Which means you need a new bed.” OK thanks I’ll try the paper thing in a few minutes… is there another test I could do with the wires of the bed itself? What do you mean exactly by “losing wires in the heat bed”? Something broken?
The capacitors can retain charge for weeks. There is potentially enough amperage in there to injure an adult. For a $35 part, it’s usually not worth the risk. Sounds like you came out of it alright though.
The heat bed is a series of wire loops. Think of them like the filament in a light bulb. Sometimes one or more of those loops will burn out, especially on the older beds. If it is fried, you definitely want to go with a 24 volt replacement and 24 volt power supply. It should halve your bed heatup time.
OK I tried putting many paper sheets on top of the bed and still it does not reach 85C (this time it went up to 83C).
After the temperature reaches a maximum value (ie lower than the set temperature of course) it starts going down… why? shouldn’t it keep a constant temp. at least?
Still thinking the bed is the problem? How to infer it’s a power supply vs bed problem?
It could be the bed Thermistor, which is what measures temperature. You want to point one of those inexpensive $30 infrared thermometers like you can get from an automotive or hardware store at the bed and see what temperature it is actually getting to, and if it is actually dropping. It may be that the Thermistor is either becoming unstuck from the bed and just needs re-taped to it, it might be failing (fluctuating temperatures is a symptom of one going bad) or the thermistor could be just fine and the bed itself is what is failing.
Best case scenario you need to retape the thermistor to the bottom of the bed. Worst case scenario you need a new thermistor or new bed.
