Since repairing the Dolce Gusto pod coffee machine a few years ago, I upgraded to a proper espresso machine, The Krups “Espresso Piano” XP521040.
It was another freebie hand-me-down from a relative who no longer wanted it, so I have no particular opinion on whether it’s a great machine compared to the competition or anything like that – it’s merely a step up from using a pod machine (with or without re-usable pods).
A while back it started acting a bit weird – especially if I was making more than one coffee – it would seemingly enter what I thought was a cleaning cycle.
It just keep pumping water out into the drip tray until I switched it off at the mains.
More recently it failed more completely. As soon as the machine was switched on at the wall (even if the machine had not been switched on by it’s own power button), it would start pumping water into the drip tray – the only way that the pump could be switched off was at the wall socket.
Diagnosis
Starting by opening the machine up from the bottom, I quickly found the controller board.
For a consumer product, the circuit board is surprisingly well labelled.
There are a number of braided wires, connected with spade type connectors.
After a bit of probing around, I noticed that the PCB had a slight scorch mark at the base of one component. It was very small, I actually didn’t notice anything during the initial investigation - it was only when I’d just about given up and was packing away everything to dispose of that I spotted it.
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| The scorch mark around the leg of the failed component |
The component in question is a BT134. This is a triac, and it is connected to the pad with the spade connector labelled “pump” – So it seemed a likely culprit.
Tracing the connections about the machine appears that the pump has a direct AC connection, so my guess as to what happened is that the component failed and it’s failure state effectively held it open instead of in a “switched off” state.
This does explain why the pump was active only with mains power, regardless of the rest of the machines state.
The fix
The fix itself was plenty straight forward. I sourced a replacement BT134, I swapped it out, which requires no more than a little bit of soldering.
Putting it all back together, I tested it and it works fine.
There’s nothing more to it really than that, I just want to write up and publish this in case it helps anyone else who may be having similar issues with our machine. But as always, these posts should be treated as a diary of what I did, and are in no way a how-to or guide. I am by no expert, what you do with information I provide is at your own risk.
