Well my Rambo melted

[deadpool66]

Noticed my extruder motor was making funny noises. Then I smelled burning took the Rambo out and it was melting.

Can I just resolder the heated bed wire to the back of the board? Hopefully the capacitor wasn't damaged.

Or does anyone have a used Rambo they wanna sell?

Figures right after I set up my new printer the Rostock melts down. Maybe I should replace the psu as well as it is the old viotek.

[TwoTone]

We just upgraded to DuetWiFi so I have a Rambo I'd sell. PM me.

[Qdeathstar]

The duet wifi is what your should get, not a rambo

[deadpool66]

We're can I buy one of those?

[Xenocrates]

https://www.filastruder.com/collections ... /duet-wifi is one spot

More expensive than say, a used Rambo, less than a new one.

[Christian79]

Just an FYI but you can buy a new connector block on DIGI Key for a few dollars assuming the board is ok. Looks like you had a loose wire that caused extra resistance and therefor heat at the connector.

Here is just one way to fix it... viewtopic.php?t=8809

The manufacture went through sever types of headers throughout the design, the screw type are not my favorite for the reason you found out.

http://reprap.org/wiki/Rambo

Here is a 2PIN replacement example, its mate can be found lower on the sales page... https://www.digikey.com/product-detail/ ... -ND/124168

Good Luck

[Eric]

Can I just resolder the heated bed wire to the back of the board? Hopefully the capacitor wasn't damaged.

Yes, you could, and it would probably work. It'll look ugly, of course, and it complicates future disassembly without some kind of connector.

[gchristopher]

If you disconnect the bed and the RAMBo still runs, and you can measure a good 12V signal across the bed terminals, then there might be a good chance the FET and related circuitry are okay? That might make it worthwhile to rework the connection somehow.

I decided that putting 10A through those screw terminals is just a bad idea and switched to a SSR, even after reworking to a plug terminal.

[lightninjay]

This could be completely off-base, but if you tinned your wire leads before putting them in the terminal block, don't. This limits the amount of surface area that the terminal block is able to make contact with and can cause what you have experienced. This same issue has happened to at least two other members on these forums in the past, and if I recall correctly, it was due to their tinning of the heated bed wire.

[Eric]

Not off-base. Things that are soldered then clamped are samll time-bombs. A soldered wire under a screw clamp will tighten up fine, but then the soft solder under pressure flows over time, allowing the wire to spread out and the clamp to become loose. Loose connections produce heat. Heat melts plastic.

[deadpool66]

The leads were not tinned I checked when I took it apart. I cut the burnt part of the connector off and soldered the wire to the back of the board.
Good news it works not pretty but its not getting hot anymore. The bed temp seems to climb higher and faster now.

[sunkenbier]

I have an identical issue occur this week. My wires were not tinned and there was no wire bits protruding that cause a short.

[wdmarine]

When I was building my v3, I was told by a German friend that one should NEVER put a stranded wire in a screw down connector, tinned or otherwise, but especially not tinned. He was horrified that I would even consider it.

Instead, in Germany it is common knowledge and practice to always use a ferrule. In all my years of electrical work and electronics, I did not know this. Apparently, wire ferrules just aren't popular in the US. Go figure.

The tool used to crimp the ferrule is really cool. It crimps the ferrule equally inward in four opposing directions.

I've seen German wiring, house and other, and it is always very neat, organized, and perfect.

Here's where I got my ferrules and crimp tool:

https://www.amazon.com/gp/product/B06XC ... UTF8&psc=1

Here are some photos:





Update: I just noticed that this image I nabbed off the web shows more than one wire in each ferrule, which is also a big German no no. At this point, I am trusting the Germans!

[Xenocrates]

As someone who does industrial electrical work at times, those ferrules (bootlaces is another term I see a lot), are great. Any system where I expect wires to ever move from a terminal block will probably be fully crimped. However, for household wiring in the US, solid core wire is the most common. And unlike many chunks of europe (which I believe includes Germany), we are not expected to attach our own plugs to appliance cords (A common source of stranded wire work). Thus most americans work very little with stranded wiring.

As an aside, I do trust the Germans fairly well with electrical work, as the german DIN standards define a huge chunk of the terminals I deal with, however the pictured solution is far better than multiple ferrules there, as the screw terminal is relatively small in area, and multiple ferrules would make for poor contact, given that the insulation on the rear would make them both enter at angles. However, if it were a larger terminal area, I would agree multiple ferrules are better.

[geneb]

If you guys watch part 2 of the live build video of the H2 I did last Saturday (6/3/17), you'll see me using that exact tool, for the reasons mentioned. If you don't want to slog through the whole five hours, it's towards the end where I'm wiring up the power connector/switch for the Mini-Rambo.
Here's a link: https://youtu.be/ZeD0h8R94Mw?t=16779 (it's right where I show the use of the bootlace crimps...)

g.

[3D-Print]

Agree, I used ferrule's when I upgraded RoStock V2 from a Rambo to a Duet. They are supper slick!

Also agree with Xenocrates...... A Duet is the way to go!!!