Repairing a Krups Nespresso XN2120 water pump

[jimmyc_]

Hi all,

I've got a Krups Nespresso XN2120 https://www.bean2cup.org/kaffeemaschinen/krups/626_nespresso_essenza_programm/ water pump that stopped functioning. It's a Sysko water pump that runs on 230V. I've checked the inputs from the PCB to the Sysko water pump and found 198V was sent to the water pump, instead of 230V. I assume that's the reason why the water pump does not pump when the Make Coffee (either espresso or lungo) button was pressed.

On the XN2120 PCB I've replaced the 680uF and 220uF capacitors. I've also tested the replacement capacitors before installing them.

Any ideas?

[Renate]

I don't know anything specifics, but I worked on an espresso machine once.
The pump was a simple solenoid with a metal slug and two one-way valves.
It was fed line voltage, but through a diode to make it more "pulsey" and to divide (what would be the double) frequency.
So any DVM voltages on the coil would be a bit misleading, whatever they were.

[Jeroen3]

Did you download the repair manual?

Krups provides them with extremely detailed instructions and schematics for their machines.

For example for my machine it states the pump has a thermal fuse, where the fix is "replace pump", because it is embedded in the pump (pump has 4 wires).

[jimmyc_]

I don't know anything specifics, but I worked on an espresso machine once.
The pump was a simple solenoid with a metal slug and two one-way valves.
It was fed line voltage, but through a diode to make it more "pulsey" and to divide (what would be the double) frequency.
So any DVM voltages on the coil would be a bit misleading, whatever they were.

Oh! I didn't know anything about that pulsey pulse... This is new to me. Did it work for you using an analog mm?

[jimmyc_]

Did you download the repair manual?

Krups provides them with extremely detailed instructions and schematics for their machines.

For example for my machine it states the pump has a thermal fuse, where the fix is "replace pump", because it is embedded in the pump (pump has 4 wires).

I've looked around and found only the user manual... Do you have a link to the service repair manual for the XN2120?

[Renate]

Well, if you've got no voltage then the diode is open or the control isn't sending anything. If it looks exactly like line voltage then the diode could be shorted. If the reading looks funny, it's probably ok. You can also try your meter on a high DC range XXX.X V and see if it's DC. (Don't go to a lower range if you're not seeing anything because it could be pure AC.) Or you could just check the diode.

In my case, it was that from disuse the slug had gotten all gummed up. The pump core came all apart, but I forget how.