I have a ~20 year old BOSCH TKA8011 coffee maker. (Of the filter coffee kind.) It is fairly simple: it has an on/off push-button, a decalcify push-button, and a low-water-level indicator which triggers a slow brewing function. That's all; no delayed start function, no LCD display, no bells and whistles.
Actually, I would be much happier with it if it only had a mechanical on-off switch, but apparently a mechanical on-off switch is a low-end-appliance-feature-only, so if you want a high-end feature like a removable water tank, then you have no option but to buy an appliance with a whole bunch of useless electronics. But I digress.
Some time ago while washing it I accidentally poured copious amounts of water onto it, which very possibly got inside. It stopped working. It did not trip any circuit breaker, it was just dead. I dried it for several hours using a fan, then it started working again. A few weeks after that, I left for a couple of months. The day before I returned a cleaning lady had visited my apartment, I have no idea what she may have done. When I tried to make coffee, half-way through the brewing process, the safety circuit breaker dropped.
Since this "safety circuit breaker" thing might have different names in different countries, let me clarify what this is: it has nothing to do with excess current, it breaks when it detects a leak of electricity to the ground, probably even a very tiny leak. It has a button that you can press to test that it works.
I experimented enough to know for sure that what triggers the safety circuit breaker is the coffee maker and not any other appliance or the wall outlet.
I gave it another round of drying, but the situation remained the same: the safety circuit breaker would drop every time I tried connecting the plug of the coffee maker to the wall outlet.
I opened up the appliance, (why do they make it so hard to open them up?) and examined it. The 230V go directly onto the PCB, while the ground goes everywhere else. On the PCB they have an incredible amount of electronics for a coffee maker; I saw electrolytic capacitors, ceramic capacitors, a transistor, a zener diode, a bunch of blocks that are probably power diodes, several resistors including a power resistor, and a bunch of surface-mount components that I could not identify. It has a tiny heating element that is mounted against the hot plate using heat-conductive paste like the one used between CPUs and heat sinks. The paste was probably dead after 20 years, but I am pretty sure that's not the problem.
Believe it or not, the mere act of opening up the coffee maker, without actually doing anything else with it, improved its condition. I was now able to plug it in, and the safety circuit breaker would not immediately drop. It would only drop if I went ahead and pressed the "Start" button.
I removed the PCB from its place and I applied a generous amount of WD-40 on both sides of it; no further improvement.
I disconnected the heating element; still no further improvement.
So, reluctantly, I resorted to the one thing I knew would solve the immediate problem of not being able to make coffee: I disconnected the ground. Of course, with the ground disconnected, the safety circuit breaker is not triggered, because there is no ground-leak for it to detect.
Here are my questions:
How unsafe is this? (Is it okay as long as I am present when the appliance is operating? Is it a "better solve it within a week" type of thing? Better solve it within a month? Evacuate apartment building immediately?)
Any ideas / hints / guesses as to what may be wrong and what I could do to properly fix it?