10" relay clicking in and out

Hello,

im having some issues with my relay. When I set the printer to auto heat or send it a print it starts to heat the nozzle and then the relay for the print bed cuts in and then just clicks in and out. It's clicking roughly every half a second. This doesn't stop until I cut it out as the wires to the relay board started to get hot.

i measure 12v at the D8 port and when I wire the relay direct to 12v it fires too. I'm wondering if the signal through D8 is too fast for my multimeter and it's actually pulsing.

Now, just for reference I have changed to the large display and updated the code to reflect this and I've not really used the printer in a while due to a house move so I can't remember whether this issue was apparent since I changed it. And I finally have the requirement for an urgent print as my bbq is broken and I need to print a new part for it!

Any thoughts?

What do you mean by 10" relay? How exactly is your heated bed connected to the RAMPS 1.4 shield?

Check the terminals on the relay board. Make sure the plastic hasnt started to melt or warp, if they havnt then tighten all the terminals. The wires like to get a little loose and when that happens, little archs between the wires and the terminal start to happen. This will cause the terminals and wires to get hot and melt.

Relay chatter/skipping can also be an indication of internal failure, e.g., the actuator coil is frying. It maybe that when you hook it up directly to 12V, there is sufficient current to activate it..., but when you hook it up to the mosfet driver, there isn't..., though I admit, that seems unlikely, since that mosfet can drive the 8" HB directly...

Thanks for the replies.

I meant to type 10" print bed.

I've checked all the terminals and it seems fine, and regardless, as soon as I hook it up to another 12V supply it fires straight open.

Could it be the signal from the Ramps board is fluctuating and causing it to opne and close? Anyone know where to check this in the code?

Thanks

Have you tried another relay?

have you run a PID auto tune on it? M303 T0 SXXX (xxx being the temp you want to tune to)

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Originally Posted by ZorAxe

Have you tried another relay?

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No, I guess I could try an automotive one and see what happens.

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Originally Posted by sniffle

have you run a PID auto tune on it? M303 T0 SXXX (xxx being the temp you want to tune to)

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I'd love to know what that all means

I'd say try another relay first. That will tell you whether the relay is the problem, or not.

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Originally Posted by Stuartknight1

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I meant to type 10" print bed.

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Understood. I only meant to suggest that the ramps signal, when it's working, can sink/supply a lot of current on it's own. Per the other suggestions, I would do things in the following order:

1. Closely inspect the heat pad, to ensure nothing has damaged it in such a fashion as to alter the current path. Unlikely, but what the heck.
2. Replace the relay. It's the cheapest/easiest thing to try.
3. Replace, or debug/repair the RAMPS. This is costly in either time or money, but is the next most likely problem area.
4. Fiddle with the firmware. This seems like the least likely point of failure and you might spend a lot of time trying to find the problem.