I did some routine cleaning and lubricating on my machine this morning and found this harrowing scene...



We're two users of this machine and neither me nor my girlfriend remember forgetting the machine ON or running out of water.

What could possibly explain this? The machine still runs perfectly on the two heat settings, although I'm going to change these connectors ASAP.

Thanks!

Have you ever removed that specific connection before?

This is sadly common on quick-disconnect lugs. If you have removed that wire before, it's possible the contact patch between the blades was very very small causing excessive heating, as high current passes through. If that is the case, frequent on/off cycles will cause more current to flow during initial heating of the boiler. This long period of high current will be enough to melt your connections.

Think of it this way. With a quick disconnect, surface area matters. You can have 14AWG wire that is rated at X amps / Y volts, but with a bad disconnect, you may only have the surface area of a few pinheads to transfer 1500W of power.

I don't think you machine is damaged, but your connection point could stand to be replaced.

Another possibility is the connection becoming loose at the terminal block. This can overheat the wires where they connect elsewhere. I found that when servicing a Maximatic.

I think it's a bad connector right there. Note you have two short connecting wires, one goes from the safety thermoswitch to the low watt terminal, and another from the low watt terminal to the high watt terminal. They are both fried where they connect at the low watt terminal and nowhere else. This point in the circuit is carrying current whenever the switch is on in this machine, and carries quite a bit of current when on the high setting. A bad connection or bad crimp at one of those connections would generate a lot of heat right there.

Hopefully the low watt terminal spades will clean up fine, and you can just replace those two wires and connectors. If you have a trusted espresso machine service shop nearby, they should be able to quickly do that job and give the elements and other connections a check-up. I think a competent appliance repair shop could do that also.

That looks like a loose spade. It will arc electric if it is loose. That arching generates heat in the connector which will eventually melt the plastic shroud. The good thing, you can easily change that spade connector. There should be plenty of wire in the machine and the connector just crimps on.

cannonfodder wrote:There should be plenty of wire in the machine and the connector just crimps on.

+1

You could do that also - just DIY those two connectors on the old wires. Some would advocate crimp + solder if you don't have a good crimping tool.

Look for audiophile grade connectors($$$) if you want to ensure better contact OR just hardwire the darn thing by making a sound mechanical connection and then soldering it (Would be my preferred solution), solder should never be used as electrically conducting glue (which is how most people seem to use it)

Marcelnl wrote:solder should never be used as electrically conducting glue (which is how most people seem to use it)

Can you say more about that?

I would think solder on the heating element connector would be a bad idea, just because of the potential temperatures involved. But, you have water (hopefully) to adsorb and dissipate the heat, keeping the temperature below the melting point of solder.

+1 on the high grade connector recommendation. More contact surface == higher watt energy throughput at lower temperatures.

Most people that make an electrical connection using solder seem happy to keep the pieces of wire and or metal together, heat them and let the solder flow between the two thus connecting the parts. if done properly the to-be-connected parts are first mechanically joined, i.e. In such a way that they would not really require solder to keep an electronically sound connection, only then they are to be soldered.

Keeping the pieces that are soldered motionless until the solder has settled is also important.

Solder is a poor conductor and each and every joint can be heard in audio, they add resistance if not soldered properly and joints that have not been allowed to settle motionless during cooling break quite easily (f.e. Due to vibration) very poor solder joints can even act as a diode/ transistor.
http://www.epemag.wimborne.co.uk/solderfaq.htm

Don't get me started on soldering in audio equipment


Ops one would hope that the temperature of any joint would remain well under the temp at which solder starts flowing...the typical plastics used as shown in the picture can be expected to melt well before most solders start to melt (~188'C), that is : unless you suggest to use Woods metal