my hotend can't reach 240° hi guys i've got a hardbot hadron with a brand new ramp and arduino board, heating cartidge and 100k resistance my old card could hardly reach 190° , that's why i sent it back ti the customer service, and they gave me new boards i plugged the new ramp, and make the first try and surprise, my hotend reaches194° and i was asking for 240° heated bed is ok at 100° i tweaked the small potentiometer of the power supply to increase voltage to 13V my hotend reaches 204° it's not hot enough to print abs ,where could this problem come from????? anyway,something's going wrong and i can't print since january please help me! thank you https://reprap.org/forum/read.php?1,322239,322239#msg-322239 Mon, 16 Mar 2026 17:12:13 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,322239,322579#msg-322579 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322579#msg-322579 this one is brand new , and i've got another one in the cupboard
so i might try
thanks for this advice]]> jaak lab General Mon, 10 Mar 2014 07:01:31 -0400 https://reprap.org/forum/read.php?1,322239,322448#msg-322448 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322448#msg-322448
If you jumper the cartridge to +12/+13V and ground manually instead of to the board, while watching the temperature does it still plateau at 190?]]> DaveX General Sun, 09 Mar 2014 22:16:53 -0400 https://reprap.org/forum/read.php?1,322239,322412#msg-322412 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322412#msg-322412
Quote
Ohmarinus
Okay, that sounds pretty good.

But, on the site of digikey it says the resistor is 3W?
How do you get to 30W?

Oh, and I can't find a seller besides digikey. I am in Europe and Digikey rates me around 55 dollars for postage.. :O

Oh god...that's insane! ::o

For me shipping from digikey is an $8 flat fee but I live in Canada. I didn't think it would be so expensive for you. Since this is just a pretty standard 4.7ohm wirewound, flame proof, through hole resistor you can probably get one from any electronics parts wholesaler. Element14 (Farnell) is in the UK so they may have better shipping fees and they will likely have through hole resistors. I have no I idea why the shipping is so expensive. I have been looking into worldwide shipping and I managed to find a "light packet" service from Canada Post that is quick and costs about 6USD. Maybe Digikey does not bother to find cheap international shipping. Do you have any local electronics parts stores?

As for the power rating. The resistor is rated at 3W but you can push it well over its rated power. These resistors have fixed resistance so by ohms law (V = IR, and P = VI so P = V^2 / R) the power is dependent on the voltage you run through the resistor. For a 4.7ohm resistor running at 12V the power is about 30.6W. Running the resistor at 10x its rated power is ok as long as you have adequate thermal conduction between the resistor and the heat block as this prevents the inside of the resistor from overheating. If you were to run 12V through this resistor in air (insulator) it would overheat and fail. Standard J Heads use 6.8ohm resistors like the one I linked to but 6.8ohm only gives about 21W which is a little low. That's why I chose to use 4.7ohm resistors. I done all of my testing with these and they are very reliable as long as you are careful ensure good conduction to the theater block.

Eric]]> RP Iron Man General Sun, 09 Mar 2014 19:36:04 -0400 https://reprap.org/forum/read.php?1,322239,322374#msg-322374 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322374#msg-322374
Quote
RP Iron Man
Quote
Ohmarinus
Quote
RP Iron Man
Could be a fluke heater cartridge.

Most heater cartridges come from China and many of them have incorrect specifications. I would just save yourself the trouble and replace it with a through hole resistor heater from DigiKey.

EDIT: a 4.7ohm through hole resistor heater will provide ~30W at 12V which should be more than enough. I have used this one from digikey and it works great. It only costs 85 cents...

Eric


Hi Eric, how long does it take to get to 200º with that through-hole resistor?

I am now using a ceramic cartridge, but I reckon it might be better to use a resistor so I can insulate my hotend better. However, if it takes 6 minutes or something, then I'll stick with what I got. Now it's on temp in about 1 minute.

Hey Marinus,

Heating times are dependent on the heat capacity of the "melt-zone" in question. This is a function of the mass and material used (aluminium, brass, etc...).

I use this 4.7ohm resistor for my Prometheus Hot End and using a standard MZ length of about 16mm (material is aluminium though mass is less than most hot ends) it heats above 200C in less than 1 minute. I think 30W is easily enough even for a larger MZ. If you want it to heat up lightning fast you can use a resistor with lower resistance though I would not recommend it as these through hole resistor are already used over the rated capacity. I don't think you should go over 30W.

Eric

Okay, that sounds pretty good.

But, on the site of digikey it says the resistor is 3W?
How do you get to 30W?

Oh, and I can't find a seller besides digikey. I am in Europe and Digikey rates me around 55 dollars for postage.. :O]]> Ohmarinus General Sun, 09 Mar 2014 17:49:34 -0400 https://reprap.org/forum/read.php?1,322239,322320#msg-322320 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322320#msg-322320 vreihen General Sun, 09 Mar 2014 15:34:11 -0400 https://reprap.org/forum/read.php?1,322239,322315#msg-322315 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322315#msg-322315
Quote
Ohmarinus
Quote
RP Iron Man
Could be a fluke heater cartridge.

Most heater cartridges come from China and many of them have incorrect specifications. I would just save yourself the trouble and replace it with a through hole resistor heater from DigiKey.

EDIT: a 4.7ohm through hole resistor heater will provide ~30W at 12V which should be more than enough. I have used this one from digikey and it works great. It only costs 85 cents...

Eric


Hi Eric, how long does it take to get to 200º with that through-hole resistor?

I am now using a ceramic cartridge, but I reckon it might be better to use a resistor so I can insulate my hotend better. However, if it takes 6 minutes or something, then I'll stick with what I got. Now it's on temp in about 1 minute.

Hey Marinus,

Heating times are dependent on the heat capacity of the "melt-zone" in question. This is a function of the mass and material used (aluminium, brass, etc...).

I use this 4.7ohm resistor for my Prometheus Hot End and using a standard MZ length of about 16mm (material is aluminium though mass is less than most hot ends) it heats above 200C in less than 1 minute. I think 30W is easily enough even for a larger MZ. If you want it to heat up lightning fast you can use a resistor with lower resistance though I would not recommend it as these through hole resistor are already used over the rated capacity. I don't think you should go over 30W.

Eric]]> RP Iron Man General Sun, 09 Mar 2014 15:18:44 -0400 https://reprap.org/forum/read.php?1,322239,322295#msg-322295 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322295#msg-322295
Quote
RP Iron Man
Quote
jaak lab
it's a magma hotend 40W
i usually use ABS

Could be a fluke heater cartridge.

Most heater cartridges come from China and many of them have incorrect specifications. I would just save yourself the trouble and replace it with a through hole resistor heater from DigiKey.

EDIT: a 4.7ohm through hole resistor heater will provide ~30W at 12V which should be more than enough. I have used this one from digikey and it works great. It only costs 85 cents...

Eric


Hi Eric, how long does it take to get to 200º with that through-hole resistor?

I am now using a ceramic cartridge, but I reckon it might be better to use a resistor so I can insulate my hotend better. However, if it takes 6 minutes or something, then I'll stick with what I got. Now it's on temp in about 1 minute.]]> Ohmarinus General Sun, 09 Mar 2014 14:36:40 -0400 https://reprap.org/forum/read.php?1,322239,322261#msg-322261 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322261#msg-322261
Quote
jaak lab
it's a magma hotend 40W
i usually use ABS

Could be a fluke heater cartridge.

Most heater cartridges come from China and many of them have incorrect specifications. I would just save yourself the trouble and replace it with a through hole resistor heater from DigiKey.

EDIT: a 4.7ohm through hole resistor heater will provide ~30W at 12V which should be more than enough. I have used this one from digikey and it works great. It only costs 85 cents...

Eric]]> RP Iron Man General Sun, 09 Mar 2014 13:16:47 -0400 https://reprap.org/forum/read.php?1,322239,322257#msg-322257 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322257#msg-322257 i usually use ABS]]> jaak lab General Sun, 09 Mar 2014 13:12:07 -0400 https://reprap.org/forum/read.php?1,322239,322243#msg-322243 Re: my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322243#msg-322243 My guess is whatever you are heating the hotend with is wrong or defective.]]> cat.farmer General Sun, 09 Mar 2014 12:09:09 -0400 https://reprap.org/forum/read.php?1,322239,322239#msg-322239 my hotend can't reach 240° https://reprap.org/forum/read.php?1,322239,322239#msg-322239 i've got a hardbot hadron with a brand new ramp and arduino board, heating cartidge and 100k resistance
my old card could hardly reach 190° , that's why i sent it back ti the customer service, and they gave me new boards
i plugged the new ramp, and make the first try
and surprise, my hotend reaches194° and i was asking for 240°
heated bed is ok at 100°
i tweaked the small potentiometer of the power supply to increase voltage to 13V
my hotend reaches 204°
it's not hot enough to print abs ,where could this problem come from?????

anyway,something's going wrong and i can't print since january
please help me!
thank you]]> jaak lab General Sun, 09 Mar 2014 11:56:09 -0400