I've been pulling my hair out with this one. The coffee machine just quit working one day, a little pop then no sounds, no lights, nothing, so I had a look inside. A quick look at the circuit board revealed a blown triac, so I tested all triacs and they were all good except the one in the red circle (see photo). Following the wires to see what that Triac was powering, I noticed that the solenoid valve looked a bit rusty. A quick test revealed that it was also faulty. The replacement solenoid valve is hard to find and costs around €25 so I wanted to make sure everything else was working before ordering it. I replaced the faulty triac and removed the solenoid valve from the circuit. Powered up, the pump is now on (it shouldn’t be) but there are still no lights or anything else. I couldn’t find a schematic anywhere, so I had a closer look at the power section (see my schematic). At first, it looked like a voltage doubler but that didn’t seem to make sense since there’s plenty of voltage to go around. Since the x capacitor should act as a large resistor to limit current, this must be some sort of rectifier. The 2 zener diodes are a bit confusing. Why clamp the voltages and then use a linear regulator? Anyway, I started testing voltages. The AC voltages were all normal, but getting into the section that powers the ICs and the lights, there are some issues. Across the input of the 78M05, DZ1, and C3 there are only 2.8 volts. I was expecting 8.2v. Of course, there’s no output voltage on the 78M05 which explains why there are no LEDs lighting up. Across C4 and DZ2 are .2 volts! Needless to say, I tested all the Diodes with my multimeter and they all seem to be good. I desoldered DZ2 and tested it out of circuit with load and it is functioning ok although the zener voltage should be 5.1v and I only get 4.5v. I even replaced it temporarily with a through hole 5.1v zener, but the resulting voltage in circuit was the same. I tested all the caps with my ESR meter and they’re all good. I took out C4 just to make sure, and it checks out with no leakage or issues. With all the parts back in (except the solenoid valve) I turned it on and decided to inject 9v across the 78M05 input. Suddenly the pump stopped and the LEDs lit up and went through what looked like a start up sequence. Sadly, with this little trick there’s still no control over the buttons or anything else. Since the logic section after the 78M05 seems ok, I suspect that if I can get the power section working properly, the machine should perform as usual except for the solenoid valve which I could then justify replacing. Unfortunately, I’m running out of ideas since all the caps, diodes, resistors, triacs, and MOVs test good, as far as I can test them. There are no fuses to be seen anywhere. Does anybody have any ideas? The Nespresso Delonghi is quite expensive in this country at about €300 so I really don’t want to just throw it away and buy a new one.