Heated Bed Not Heating.

I am assembling my new Pegasus 12" printer and I am also upgrading to PID control for the heated bed. Now I do have a Prusa IV3 12" with a PID controlled heated bed. So I have some experience with getting it to work.

I am following this thread: http://3dprintboard.com/showthread.p...-bed-relay-PID

But I cannot get my heated bed to heat. Right now PID is disabled in Marlin as I am attempting to pass the following command through S3D: M303 E-1 S100 C8. After that didn't work I attempted to heat the bed by turning it on in S3D, with no luck. After that I double checked all my wiring and used my multimeter to check for continuity between connections.

What am I missing? If need be I can provide an explanation of my wiring, but I literally followed the wiring on my already working Pruse IV3.

Update: I am not getting continuity across the +/- terminals on the heated bed.

Pegasus still uses RAMPS, right? You ran 12V to the 11-amp inputs on RAMPS?

I assume you've already wired up the SSR. The MakerFarm website says the Pegasus heat bed has an integrated relay. You've jumpered across the relay contacts, right?

The LCD reads room temperature for the heat bed? If it is showing MINTEMP or MAXTEMP, Marlin likely won't let you turn the heater on until you fix the thermistor problem.

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Originally Posted by printbus

Pegasus still uses RAMPS, right? You ran 12V to the 11-amp inputs on RAMPS?

I assume you've already wired up the SSR. The MakerFarm website says the Pegasus heat bed has an integrated relay. You've jumpered across the relay contacts, right?

The LCD reads room temperature for the heat bed? If it is showing MINTEMP or MAXTEMP, Marlin likely won't let you turn the heater on until you fix the thermistor problem.

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So I determined the problem after speaking with Colin. I was told in another thread to remove the small wires that attach to the relay and leave the big wires in their respective places and use it as such.

Well Colin confirmed that this is incorrect, there is a connection/trace that I need to connect one of the wires to. So later today or tomorrow after work, I will resolder this connection and attempt to heat the bed.

You are correct, it reads room temp 30*c so I know the sensor is working.

Yeah, just removing the lightweight wires would leave the bed relay contacts in the normally open state, which wouldn't work. Hence the question about jumpering between the contacts being switched by the relay. I've never seen one of the heat beds with the relay. I'm not sure I follow what Colin has told you to do, but if it works out, great.

Also note that there are small LEDs near each of the MOSFETs on RAMPS. With 12V applied to RAMPS, those LEDs toggle on and off with the MOSFET states. They can be handy as an initial diagnostic on whether the RAMPS output is turning on and off.

Quote:

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Originally Posted by printbus

Yeah, just removing the lightweight wires would leave the bed relay contacts in the normally open state, which wouldn't work. Hence the question about jumpering between the contacts being switched by the relay. I've never seen one of the heat beds with the relay. I'm not sure I follow what Colin has told you to do, but if it works out, great.

Also note that there are small LEDs near each of the MOSFETs on RAMPS. With 12V applied to RAMPS, those LEDs toggle on and off with the MOSFET states. They can be handy as an initial diagnostic on whether the RAMPS output is turning on and off.

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Thanks for that tip.

Essentially he is giving me the same advice that you are.

Edit: I got it fixed.

Quote:

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Originally Posted by BLKKROW

Thanks for that tip.

Essentially he is giving me the same advice that you are.

Edit: I got it fixed.

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i just built a pegasus for a friend and notice that too. the bed comes with a automotive relay. but from past experiences this big beds goes up and down a lot when not using PID TEMPs .

i was wondering is you can post a picture of what contacts you jumped. i dont have a multimeter in hand so will be very helpfull for in order to install the SSR.

thanks

Quote:

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Originally Posted by pichuete

i just built a pegasus for a friend and notice that too. the bed comes with a automotive relay. but from past experiences this big beds goes up and down a lot when not using PID TEMPs .

i was wondering is you can post a picture of what contacts you jumped. i dont have a multimeter in hand so will be very helpfull for in order to install the SSR.

thanks

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http://imgur.com/LHksYTw

Hopefully this helps. I have removed the smaller wires that were used for the relay. Instead I have it hooked up through my PSU and the SSR. The small wire you see is for the bed sensor.

Hi

Just to clarify a bit:

At least on my printer, the relay is on an external board and not part of the heated bed. It is not real clear just how the relay on the heated bed would work. To use an SSR, you simply throw away the supplied externally mounted relay and replace it with the SSR.

Bob