Bed not heating

Jmaxime89

@phaedrux Hello, thanks for the fast reply !

Here's the pictures. Talking about the terminal, I can't really see anything wrong with it, however it feels a little bit wiggly. It never occured to me to look behind the board to see if something is obvious

I will report back soon, when I remove the board

Jmaxime89

So I took the board out of the machine, and the negative lead crumbled to dust.

As far as I can see, it doesn't seem to have any damaged anywhere else.

Do you think it's something a soldering iron could fix or potentially the whole trace is burnt out ?

Thanks once again for your help, I appreciate it

Phaedrux

When and where did you purchase the board? Perhaps it's under warranty?

Jmaxime89

@phaedrux

Spool3d, an authorised reseller in Canada

Checked out on April 25th 2020

Phaedrux

Were you using boot lace ferrules or bare wires?

Why is there 2 wires crammed in for each of red and black?

Can you get a better photo of the back? Is the board discoloured or just a reflection?

How does the inside of the terminal look? Is anything melted?

Jmaxime89

@phaedrux

I used ferrules, see my heatbed wiring (keep in mind what you saw before was a brand new heatbed I just received)

Wire is there two wires, I have no idea, that how the bed came to me. My guess is that they tried to save money using smaller gauge wires but two of each. My old bed wasn't like that. I can provide picture of it if required. Even the doubled wires have ferrules :

The inside of the terminal looks good in my opinion :

Unfortunately, I though it was just a reflection but now with the flash it's clearly discoloured :

Phaedrux

Can you give us some details of the bed heater that was installed when it originally failed?

Jmaxime89

@phaedrux Yes Sir !

Here's pictures I just captured. Let me know if you need anything else

Phaedrux

What volts, watts, amps is that heater? Does it have a brand or product sheet?

Jmaxime89

@phaedrux Hello

This is a stock Anet A8 bed.

The Stock heated bed is 12V 1.2Ohm i.e. 10 Amp Peak Current.

When I measure it, I get 1.1ohm so the bed is not shorted or anything.

Also it is very weird that no fuse blew up when the terminal toasted. It feels like an early failure of the terminal

Phaedrux

Good old Anet A8.

The fuse would only blow if the bed shorted for enough time. As you say, I don't think it shorted. The overheated like that is usually caused by a loose connection at the terminal/wire causing increased resistance.

If the terminal itself looks ok you may be able to reflow the pin with a powerful enough iron.

Jmaxime89

@phaedrux Okay, I was waiting to see if there was any way to have it RMA under warranty before touching it and potentially voiding the warranty if I had one.

I will see if I can find the terminal locally and will solder it back together.

I think it will work because with no wire inside the terminal I could see 12v. I guess tightening the terminal on the wires flexed it just enough so the burnt leg wouldn't contact with the trace anymore.

Thank you so much for your help, I appreciate it

Phaedrux

Unfortunately you're a year and a bit past purchase already.

If you're able to desolder the entire terminal and replace it I think you'll be back up and running. The ground plane there is quite large, so you'll need a powerful iron (or two smaller ones) and maybe a preheat of the area.

If that's not something you feel confident in doing yourself we may be able to work out an exchange for a refurbished unit at reduced cost subject to availability.

Jmaxime89

@phaedrux Okay thank you so much for the heads-up, my soldering iron is definitely not up to par so I will look for an other one.

I will update here once the terminal has been changed. I hope I'll be able to find an equivalent terminal locally

Thanks once again for all of your help, I really appreciate it

peter247

@jmaxime89 OR CHEAT ?

If you have the voltage but no current fit a mos-fet to do the high power switching external ?

Phaedrux

@jmaxime89 said in Bed not heating:

I hope I'll be able to find an equivalent terminal locally

if not you may be able to reflow that pin and add a bit of fresh solder.

Jmaxime89

@peter247 thanks for the idea ! I have two mosfets laying around my workshop. I'll do that for sure, it will protect the new terminal !

Jmaxime89

@peter247 I cheated !

I soldered my mosfet on it, I wasn't able to melt the negative pad but I could surface solder it.

Right now I'm running my bed PID, everything seems in order.

Thanks a million time to both of you
@Phaedrux