Temperature problem
Posted by adamcutler23
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Temperature problem July 15, 2016 09:25AM |
Registered: 8 years ago Posts: 3 |
Hi there,
I was wondering if anyone could help with an issue I have. I have a HicTop Prusa I3 and I recently had a print stop for no apparent reason. Since then, I cannot control the temperature of the hotend. When I turn the machine on, ie plug it in, the hotend heats up uncontrollably. Everything else seems to be working fine, but I checked the firmware, new heating element, thermister, all to no effect. Has this happened to anyone else?
I was wondering if anyone could help with an issue I have. I have a HicTop Prusa I3 and I recently had a print stop for no apparent reason. Since then, I cannot control the temperature of the hotend. When I turn the machine on, ie plug it in, the hotend heats up uncontrollably. Everything else seems to be working fine, but I checked the firmware, new heating element, thermister, all to no effect. Has this happened to anyone else?
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Re: Temperature problem July 16, 2016 09:00AM |
Registered: 8 years ago Posts: 84 |
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Re: Temperature problem July 16, 2016 09:00AM |
Registered: 8 years ago Posts: 84 |
1. Have you seen the magic smoke from your ramps board? It could be that the mosfet is broken
2. The thermistor could be disconnected; make sure that it reads about 100k ohms at ambient from plug to plug.
3. Does it just start heating up when you apply 12v power, or does it heat up uncontrollably when you tell it to reach a certain temperature?
2. The thermistor could be disconnected; make sure that it reads about 100k ohms at ambient from plug to plug.
3. Does it just start heating up when you apply 12v power, or does it heat up uncontrollably when you tell it to reach a certain temperature?
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Re: Temperature problem July 16, 2016 02:42PM |
Registered: 8 years ago Posts: 3 |
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Re: Temperature problem July 16, 2016 04:19PM |
Registered: 9 years ago Posts: 3,525 |
From what I read thats the mosfet gone, it's internally shorted and just supplying 12v to the bed whenever powered. You can replace them with better ones search the forums there are recommendations. I'd say best once this is done to consider using a relay - either mechanical (use bang-bang control) or SSR (use PID) to control the bed in future. The two real points of failure on ramps/mega are the regulator on the mega, and the high current involved in making a heated bed work properly.
Simon Khoury
Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
Simon Khoury
Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
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Re: Temperature problem July 18, 2016 09:33PM |
Registered: 8 years ago Posts: 3 |
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Re: Temperature problem July 19, 2016 03:54AM |
Registered: 9 years ago Posts: 3,525 |
This thread has a few alternatives [forums.reprap.org]
I bought some IRL3803 intending to swap them over but didn't need to as I offloaded the high current switching to a relay as outlined above (which I really recommend - the heated bed current through the ramps board is the no. 1 point of failure/danger). By all means replace the mosfet, its only pennies and three blobs of solder (not surface mount thankfully). But a clone ramps board is cheap, and time is money blah blah.
Simon Khoury
Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
I bought some IRL3803 intending to swap them over but didn't need to as I offloaded the high current switching to a relay as outlined above (which I really recommend - the heated bed current through the ramps board is the no. 1 point of failure/danger). By all means replace the mosfet, its only pennies and three blobs of solder (not surface mount thankfully). But a clone ramps board is cheap, and time is money blah blah.
Simon Khoury
Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
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Re: Temperature problem July 20, 2016 01:23AM |
Registered: 8 years ago Posts: 3 |
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Re: Temperature problem July 20, 2016 04:48AM |
Registered: 9 years ago Posts: 3,525 |
Yes you can change the pins.h file. Depending on the marlin version it's either one file with a huge long list of boards. Find ramps 14 efb and find pin 10 change it to pin 9. If using an RC version then there is a ramps 14 efb file separate make the same change.
Since pin 9 is set to fan maybe reassign fan to pin 10.
What Im wondering is what this is going to do for you? Unless it's just to get going again after killing a mosfet. They're the same mosfets it'll happen again.
Edited 2 time(s). Last edit at 07/20/2016 04:52AM by DjDemonD.
Simon Khoury
Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
Since pin 9 is set to fan maybe reassign fan to pin 10.
What Im wondering is what this is going to do for you? Unless it's just to get going again after killing a mosfet. They're the same mosfets it'll happen again.
Edited 2 time(s). Last edit at 07/20/2016 04:52AM by DjDemonD.
Simon Khoury
Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
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Re: Temperature problem July 20, 2016 10:12AM |
Registered: 8 years ago Posts: 3 |
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Re: Temperature problem July 20, 2016 10:32AM |
Registered: 9 years ago Posts: 3,525 |
Loads of sources. [reprap.org]
Though if your hot end damaged the d10 mosfet then it'll do the same to the d9 mosfet unless you just got an unlucky duff one on d10. Maybe put heatsinks on them and make sure a fan is positioned over the mosfets and on whenever the heaters are heating, or all the time.
It's a bit of a lottery with ramps boards I've had 4 only one had a fault which was uncut traces across the microstepping jumpers so it was locked to 1/16.
Edited 2 time(s). Last edit at 07/20/2016 10:38AM by DjDemonD.
Simon Khoury
Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
Though if your hot end damaged the d10 mosfet then it'll do the same to the d9 mosfet unless you just got an unlucky duff one on d10. Maybe put heatsinks on them and make sure a fan is positioned over the mosfets and on whenever the heaters are heating, or all the time.
It's a bit of a lottery with ramps boards I've had 4 only one had a fault which was uncut traces across the microstepping jumpers so it was locked to 1/16.
Edited 2 time(s). Last edit at 07/20/2016 10:38AM by DjDemonD.
Simon Khoury
Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
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