1 Topic by newq

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Topic: How I replaced a broken resistor in the heating element

Some time ago my hotend just stopped heating. With some trouble shooting help from the forum I quickly found the culprit: the resistor in the heating element.

Solidoodle Support refused to tell me what kind of resistor they use in their hot end (trade secret) and they needed the broken part back to offer me a replacement for $34.96. They were nice and everything but in the end not very helpful. So I decided I would replace the resistor myself.

I found out that other hot-ends use resistor with 6.8 Ohm or 5.6 Ohm and 3 Watt. The commonly used resistor are 5.5 mm in diameter so don't fit in Solidoodle's aluminum heating block which has a 5 mm hole. I found a resistor whose size fits: AC03000006808JAC00 with 6.8 Ohm and 3 Watt and ordered 10 pcs for 0.40 Euro per resistor.

Meanwhile I carefully cleaned the original resistor and found out it has 4.7 Ohm and 5 Watt. It's part number is *drumroll* ACS-5S-4R7-J. Trade secret revealed!

I made a small album where you can see how I went about replacing the resistor:

http://imgur.com/a/WO8XA

I allready put my hotend back together and gingerly raised the temperature. First to 50, then to 80, 120 and then 160. The temperature I needed to melt the PLA that's still in my hotend.

At first the resistor emitted some tiny puffs of smoke. Put it hold's the temperature and worked the wole 30 minutes I tested it and extruded several centimeters of filament without a problem. What I will do next is start a small test print I guess.

I hope this information is useful for others. It seems the resistor breaks a lot.

If you have any questions I will do my best to answer them, but keep in mind I'm no expert. If any of the experts in this forum have some input, i'd be happy to hear it. I'm not sure if the little smoke puffs are something to fear or not. smile

2 Reply by elmoret

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Re: How I replaced a broken resistor in the heating element

newq wrote:

I'm not sure if the little smoke puffs are something to fear or not. smile

Nope, just oils from your hands or the packaging.

Interesting that they moved to a 4.7 ohm. Makes sense though, from the power numbers I've seen in RH. THe 6.8 should do you just fine, just won't heat up quite as quick. Will be less taxing on the power supply, though!

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

3 Reply by jon_bondy

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Re: How I replaced a broken resistor in the heating element

newq wrote:

Solidoodle Support refused to tell me what kind of resistor they use in their hot end (trade secret) and they needed the broken part back to offer me a replacement for $34.96.

Sometimes they just shoot themselves in the foot.  This kind of behavior does them no good at all.

4 Reply by newq

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Re: How I replaced a broken resistor in the heating element

The thing is, I don't even expect them to replace anything for free if it doesn't ship broken from the beginning.

For me the Solidoodle is an experiment or a toy. It's something for enthusiasts and a beta product at best. For sure it's not ready for non-enthusiast endusers. The only thing I hoped was that they would be better in helping me fix stuff myself. And that includes telling me a stupid part number for a resistor or the hot end connectors (they are 3-647002-2 and 3-640440-3 by the way) if that's the fastest, best and cheapest way to fix the problem.

I still like my Solidoodle 2, but I now know it's just a base or starting point I bought and I will have to mod into what I actually can service. Because I'm sure this won't be the last time I have to replace the resistor. Next time something breaks I won't even bother writing to Solidoodle support.

5 Reply by danny

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Re: How I replaced a broken resistor in the heating element

the only thing that I would say is...
a heater is a device made for heating, a resistor is not a device made for heating.
you're taking a component that is rated to be able to dissipate 5w of heat, and trying to make it work as a 24w heater...

yes, it is the design that the reprap community has used for a while.

but...
http://www.ebay.co.uk/itm/Reprap-12v-40 … 3f21a77727

using a heater would be better. that will fit the 5mm hole.


Of course the biggest thing with Solidoodle claiming that everything is proprietary and a trade secret is that.

it's really not, it's all open source technology. pretty much nothing on the solidoodle is new cool and unique or not already done elsewhere.
what is unique about the solidoodle is that it has an exceptionally low price point...

6 Reply by Caucasian

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Re: How I replaced a broken resistor in the heating element

You mentioned the cost in Euro... I would imagine the cost being that high is mostly due to postage.

I can understand your frustration in this case, but at least it's one more piece of the puzzle figured out.

7 Reply by marcbuils (edited by marcbuils 2013-03-07 22:30:40)

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Re: How I replaced a broken resistor in the heating element

Thank you for your post newq, I have the same problem !

8 Reply by badgravity

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Re: How I replaced a broken resistor in the heating element

danny wrote:

the only thing that I would say is...
a heater is a device made for heating, a resistor is not a device made for heating.
using a heater would be better. that will fit the 5mm hole.

My only question would be ... can solidoodle electronics block handle this 40w element ?
Or i need to come up with some clever relay system ?

I can totally see the resistor thingie not holding up and why the hassle when there is a obvious solution ?
Also Makerbot is using 1/4 inch heating element 12v 40w and aluminium drilling is easy for snug fit smile

9 Reply by danny

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Re: How I replaced a broken resistor in the heating element

I just made this modification yesterday,
The answer is yes the electronics/supply Etc can handle a 40W heater.

10 Reply by saymo606

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Re: How I replaced a broken resistor in the heating element

just ordered the same one smile

11 Reply by Ghostling

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Re: How I replaced a broken resistor in the heating element

i had the same experience with a broken resistor and solidoodle support. they wanted me to ship a $0.50 part back to them, fill out an RMA form and wait for them to send me a replacement part. It's like they're doing it just to cause enough trouble for end users so it deters people from claiming replacements.

so in the end i did the same thing and replaced it with a 6.8 ohm resistor from mixship.com by myself.

12 Reply by badgravity

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Re: How I replaced a broken resistor in the heating element

Recieved my ( danny ebay linked ) 5mm heater and replaced the stock resistor.
Soldered wires to stock plug and wrapped heater in alu foil for snug fit.
Heater itself is longer than heater block and sticking out on both ends about 4 mm,
maybe machine new bigger block in future ?

But it works perfect big_smile

13 Reply by Skyblue

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Re: How I replaced a broken resistor in the heating element

Had same problem, purchsed a 12 volt 40 watt heater core, nichrome wire, stainless, .5mm hole from Qu-Bid.  Fits with a little kapton, works prefectly.  Shipped same day, received two days later.  Cheap and effective.

14 Reply by Marknetto

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Re: How I replaced a broken resistor in the heating element

Hi all,

Just a quick msg to say I had the same problem and replaced the resistor with a 6.2 Ohm 5 watt one, and the solidoodle is working fine.