if the TAZ we has now has the 2.0 schnozzle then it might use the 4.7 ohm >resistor as seen here:>http://www.lulzbot.com/products/heat-resistor-47-ohm>>of course the printer will work with a different resistor as long as it >provides enough heat to print. Worst case we have to insert M220 S50 to >slow it down to half speed printing until we get a better resistor...>>what value resistors do you have? any special glue?>>On Thu, 1 May 2014, Hol Gaskill wrote:>>> this is what i pull up for the part - 6.8 ohm:>> http://www.lulzbot.com/products/heat-resistor-68-ohm>>>> sounds like the most common reason for these failing is over temp from miscalibrated>thermistor - i did find those 3 i got for the type a machine and if it's the same>part i'll bring them in.>>>> on May 01, 2014, Jake <jake(a)spaz.org> wrote:>>> so i spent all evening (and some of last night) to finally spool up the >gigantic>pile of black filament for the TAZ 3D printer.>>i finally got it hung from the wall>with a dust cover over it and ready to >feed smoothly into the printer, and then>i discovered that the heating >element in its extruder head is dead.>>oh well.>>so,>we need a new resistor to go in there. I don't know what the original >spec is, but>since the whole thing runs on 24VDC and assuming 24 watts of >heat, that would be>a 24 ohm resistor or so.>>Is someone other than me interested in contacting Lulzbot>and asking >whether they want to send us a new resistor, or if they can tell us what>>part number of resistor we should get as a replacement?>>-jake>>P.S. yes i tested>the resistor and it's dead, infinite ohms, it's burned >out. When we get a replacement>we can glue it in there better than they >apparently did. If the glue goes bad it>dies.>>>>

once the resistor gets hotter than it should, it probably burns away >whatever paste is conducting its heat to the block, and runs away, so of >course there is no thermal glue there now..>>I believe putting a cyindrical resistor in a cylindrical hole in an >aluminum block is a recipe for disaster, unless you have magic thermal >glue that is also pliable, since everything is expanding and contracting >with every thermal cycle.>>I don't have any reason to believe there's anything wrong with the >thermistor, which is the temperature sensor.>>i'll probably be there on saturday. Do you know if JB weld is a good >choice for gluing the resistor in place?>>-jake>>On Thu, 1 May 2014, Hol Gaskill wrote:>>> just popped by the space and noticed the air gap - should probably use >> some kind of high temp thermal grease. my bet is that the heater was >> getting significantly above max temp but that heat wasn't getting >> conducted into the block and into the thermistor. i'll check mine and >> bring in on saturday for omni hackathon with a side of 3ding - will you >> be around? would also like to learn how to work with thermistors.>>>> cheers>>>> on May 01, 2014, Jake <jake(a)spaz.org> wrote:>>> if the TAZ we has now has the 2.0 schnozzle then it might use the 4.7 ohm >resistor>as seen here:>http://www.lulzbot.com/products/heat-resistor-47-ohm>>of course the printer will work with a different resistor as long as it >provides>enough heat to print. Worst case we have to insert M220 S50 to >slow it down to half>speed printing until we get a better resistor...>>what value resistors do you have?>any special glue?>>On Thu, 1 May 2014, Hol Gaskill wrote:>>> this is what i pull>up for the part - 6.8 ohm:>> http://www.lulzbot.com/products/heat-resistor-68-ohm>>>> sounds like the most common reason for these failing is over temp from miscalibrated>thermistor>- i did find those 3 i got for the type a machine and if it's the same>part i'll>bring them in.>>>> on May 01, 2014, Jake <jake(a)spaz.org> wrote:>>> so i spent all evening (and some of last night) to finally spool up the>>gigantic>pile of black filament for the TAZ 3D printer.>>i finally got it hung from>the wall>with a!> dust cover over it and ready to >feed smoothly into the printer, and then>i discovered>that the heating >element in its extruder head is dead.>>oh well.>>so,>we need a>new resistor to go in there. I don't know what the original >spec is, but>since the>whole thing runs on 24VDC and assuming 24 watts of >heat, that would be>a 24 ohm>resistor or so.>>Is someone other than me interested in contacting Lulzbot>and asking>>whether they want to send us a new resistor, or if they can tell us what>>part number>of resistor we should get as a replacement?>>-jake>>P.S. yes i tested>the resistor>and it's dead, infinite ohms, it's burned >out. When we get a replacement>we can>glue it in there better than they >apparently did. If the glue goes bad it>dies.>>>>>>