The S1 Cafe - Helping Your Espresso Dreams Become Reality

I've been tracking down an autofill problem on an S1 VII I've owned since 2007.
I noticed this resistor on the board that looks like it should not be there. Anyone seen anything like this?
I have narrowed the issue down to when the fill probe ground is connected, the fill does not work. Solenoid, valve, and probe are good.

That errant resistor circled in your photo definitely doesn't belong there. You should get it off ASAP. Is it just sitting there or is it soldered down?
Then you have to ask yourself whether there is another spot that the resistor belongs and it got misplaced or did it just get on the board by accident.

I am unclear about your last statement. Do you mean that auto-fill works fine with the sensor ground disconnected?

I took it off. It was only held on by flux and did not appear to have been soldered down previously. It must have been there since the firmware upgrade in 2008. I cleaned the area with IPA to get the flux off. It did not correct the issue. I'm in contact with Chris's Coffee, hoping not to need a new board. It was an extra part, no empty pads anywhere on the board.

Yes, if I disconnect the fill probe ground it starts filling. It does not shut off with the ground disconnected, which makes sense. With the probe ground connected, it will not fill, even if the probe is disconnected.

There was a post abut 6 months ago from someone with the same issue. His problem was on the controller board but he was able to repair it. Turns out that the end of the water level probe wire connects to a resistor on the board and the resistor had gone bad - very rare. I am pretty sure that his post included at least one photo. However, I have not been able to find it after a quick search.

On the other hand there could be an issue where the probe inserts into the boiler that would cause the same issue. There are two bolts that hold the sensor in place. Between the bolts is a Teflon sleeve that prevents the probe from touching the boiler. If this sleeve has worn through or come out of position so that the probe actually touches the boiler you will also see exactly what is happening to you.

Problem solved. There was some stray leakage current from the boiler heating element affecting the probe ground. Replaced heater, back to normal.

Water or condensation does tend to get inside the heater element over time. Usually it just trips the GFCI breaker on the circuit. This is a first I've heard that it interfered with the fill sensor, though I can see how it would. Do you have a GFCI on that circuit?

Yes, at 20A GFCI, did not trip. I measured 400 - 600 kOhms, so not very much leakage. I cleaned up the heater I pulled out and dried it, it's now > 50 meg-ohm, so probably fine.