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Reprap Power expander for heatbed

veggienuts

Reprap Power expander for heatbed
September 23, 2015 10:20AM

Registered: 8 years ago
Posts: 7

Hello

I have wired up a 24v power supply for my heatbed on my 3d print and I am having issues I hope you guys can help with. The issue is the heatbed once power is supplied it is right away heating the bed I should have control over it but I cannot turn the power off other than by turning the socket of. Does this mean the mosfet is no good?

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dc42

Re: Reprap Power expander for heatbed
September 23, 2015 12:32PM

Registered: 10 years ago
Posts: 14,672

Are you certain you have the 24V supply + and - connections connected to the RAMPS heated bed input the right way round?

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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o_lampe

Re: Reprap Power expander for heatbed
September 24, 2015 05:12AM

Registered: 8 years ago
Posts: 5,232

Both GND pins of the power connector should be bridged too. ( only the GND pins )

Make sure, the 11A polyfuse is rated for 24V+ or remove it and use a standard inline car fuse holder instead.
-Olaf

Edited 1 time(s). Last edit at 09/24/2015 05:15AM by o_lampe.

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veggienuts

Re: Reprap Power expander for heatbed
September 25, 2015 09:05AM

Registered: 8 years ago
Posts: 7

Quote
dc42
Are you certain you have the 24V supply + and - connections connected to the RAMPS heated bed input the right way round?

Yes 100% sure I have a 24V PSU and as far as I can tell it is wired correctly. Repiter is showing the temp it just not stopping it when it gets to the default temp setting, it just keeps heating.