MakerGear Forum

Hey folks,

So I'm having an issue with the heated bed on my machine. Most of the time it never turn on, but every once in a while it does. I've got the old two brick power supply and am running Simplify. Any suggestions would be appreciated. The voltages at the terminals of the power blocks read 12, 19, 19 if you start on the spool side of the machine and work away.

How embarrassing!

Once again, I've solved the problem seconds after posting about it, and once again, the issue was the same.

Turns out the connector between the HBP wire terminal and the RAMBO board was loose.

However, the sucker keeps coming loose. Has anyone else had this problem?

are you talking about the red connector just under the bed or the connector on the rambo itself?

The connection to the RAMBO board is the problem.

Looking in there, it turns out that there's been some heat damage and the plastic has melted, which would explain the weird smell I had recently noticed.

When the heater is on, the voltage between the two wires, measured at the socket, is between 10 and 11 volts. Has anyone else had melting here?

the problem area for a melted heated bed connector is usually where the power brick for the bed plugs into the rambo board. it works a little loose, creates some resistance, it gets hot and melts. i have not heard of anyone having a meltdown where the bed itself plugs into the rambo. thats over in the same strip of connections where the extruders plug in. i guess the same thing can happen though. if its a little loose or the connection gets just a little bad it will generate enough heat to melt.

telephone1652 wrote:The connection to the RAMBO board is the problem.

Looking in there, it turns out that there's been some heat damage and the plastic has melted, which would explain the weird smell I had recently noticed.

When the heater is on, the voltage between the two wires, measured at the socket, is between 10 and 11 volts. Has anyone else had melting here?

If you're handy with a soldering iron and a solder sucker or solder wick, you can pull the connector and replace it. Or tack in a couple wires (maybe 14 ga?) and use an inline connector of some kind, if you can't find a replacement PCB connector.

Probably worth a try. A temperature-controlled soldering iron in the right place can't make the situation much worse..... although I've been known to blow that logic out of the water (and the magic smoke out of a few components) acting under that assumption!
Dale

I probably will end up pulling and replacing that connector when I get some time. Does anybody know what that style terminal is called?

The Rambo bill of materials is available at https://github.com/ultimachine/RAMBo/bl ... MBoBOM.txt . I think the connectors are near the bottom of the list. Look for the Molex 2-pin ones (that are similar to the 6-pin in the back), I think. These can probably be cross-referenced to other manufacturers, if your favorite distributor doesn't have them.

Dale

Eventually Karen at tech support shipped me new 2 pin molex connectors to replace the melted ones. As it turns out, the process was a little bit harrowing since the version of my Rambo board had one 12 pin molex socket, rather than 6 two pin sockets.

After a couple deep breaths, I cut off the melted end of the 12 pin socket and tried to slot in the two pin connector, but the individual two pin units are slightly wider than two slots on a 12 pin connector. With a little sanding of the new connector, everything went back together tightly but it was a stressier project than I was expecting. Works great now.