If you have a Rancilio Silvia espresso machine ...
... Yours probably doesn't look like this.
(And I'm not referring to the fact that it is in need of a little cleaning again.)
I went to make coffee yesterday morning and nothing happened. The pump ran, but there was no flow from the group head. The three-way solenoid valve never opened.
It was simple enough to trace the problem to the brew switch. It was also fairly simple to locate a replacement brew switch ($8 plus shipping). But that still left me with no coffee. And that's how we come to this frankenrigging.
You see, all three of the switches down the left side of the machine — brewing, hot water, and steam — are electrically-identical DPST (double pole, single throw) rocker switches with an illuminated 'ON' indicator, differing only in their markings. One pole of the brew switch activates the pump, the other the 3-way valve. The second pole of the switch, which delivers power to the valve, had failed.
However, the hot water circuit uses only one pole of the 2-pole switch. (Although for reasons I do not profess to understand without studying the circuit diagram, the wiring harness does connect to one terminal ONLY of the second pole, but not to the other.) And THAT means that as a quick field-expedient repair until my replacement brew switch comes in, I could simply swap the brew and hot water switches with no impact on the operation of the machine.
And that's why my Rancilio looks like this for the next few days.
(Yes, I'll finish cleaning it before I put everything back as it should be.)