Loud fan sounds, then heated bed cools down

And should there not be a fan over the polyfuse?

 

Fans on the robo

Power Supply: Most likely this one. Probably over amping it.
Ramps Fan: probably not this one since it's on constant 12v
Parts Fan: for cooling parts

Hexagon heatsink fans: only printers with hexagon hot ends will have this.

 

It is the power supply fan

 

measure the resistance across D8.

 

I do not have a multimeter it is definitely the power supply fan though

 

Is there somwthing else I can do?

 

I'm wondering if there's a short or low resistance line that's over amping the power supply.

Or if there's something wrong with your polyfuse.

Measuring D8 gives us a good starting point to rule out variables.

 

Ill get that multimeter and let you guys now

 

Similar issue for me, but my heat bed does not go above 63 C max. Most times not that much. It is brand new, less than one week. I have not been able to print any ABS because it will not reach 80 to allow the print to start. When it gets 59-63 C, I hear a fan kick on underneath, appears to be in the silver electrical box, and the temp drops back to room temp. I have to disconnect and shut it down a few times before I can re-try. But still no joy. All wires look in order, nothing melted off or disconnected. I am using Matter Control and Repeater on a Mac. Brand new printer.

 

There should also be a fan positioned above the ramps board which should run constantly.

 

@Guy Henry does your printer have a cork board on the bottom of the glass bed? ~60C sounds more like a loose thermistor on the glass. Do you have another device that can measure temperature like a meat thermometer or ideally an IR thermometer

 

I don't see any cork under glass. Just the gold heat element wires and connecting leads. I'll try and source a good thermometer. It got up to 66 today and then down. I am out of the classroom tomorrow and will return to check it on Thursday. Thanks, Mike.

 

Make sure your thermistor is pressed against your kapton heater then

 

I'll have to research those terms. Getting a little over my printer knowledge. Sorry. Thanks for all the ideas, though.
Robo3D Jerry said to check that fan under front right corner is working and raise it up on blocks to improve air flow to electronics.
I visually verified that fan is working.

 

Yeah Jerry didn't realize you didn't have cork board on your bottom heater (the orange thing is the kapton heater).

Thermistor is a small glass bulb looking object. It's supposed to be cover in a glob of orange silicon.

 

I did a live chat last night with Robo tech Tiffany. Cool thing is she invited me to bring it in since I am local. She said they should replace the fan under front right corner and will add the cork insulation under the bed.

 

Success! I brought it in and they replaced fan and bed heated up enough to print ABS. Finally in business.