Finally got my abrewPi in service on my fermentation fridge after 5 or 6 weeks of successful bread boarding both in my house and in the brewery (ambient temps 90 to 100 F).
Four hours after getting it in service, I’m pretty sure it burned up…only a blank white screen and won’t boot to anything but a white screen.
The BrewPi power supply was running at 12.2 volts, and the BrewPi connection is center + 12 VDC. I’m running a tiny cooling fan off of the same power supply, voltage measurements taken with the fan running…
I ordered a new BrewPi a few minutes ago since we are planning on brewing next Saturday.
Since everything has been running without issues, I’m stumped as to what the problem may be. Any ideas?
Does it still beep at startup?
If it does, it is likely just the screen that is bad.
OK, here’s a scenario…
The T-stat in my fridge is switching the full compressor load. The fridge is a commercial glass door merchandizer. I’m guessing the compressor starting load could be high enough to induce voltage spikes on the “one-wire” bus and also the AC feed to my RPI and BrewPi power supplies.
All these electrical lines are routed together (more or less) along one side in the top of the fridge.
This is the only thing that has changed. All of my previous testing and operation was away from any major switching loads.
I’m thinking that I can use some SS over-braid that I have to “shield” the BrewPI power leads and the “one-wire” buses, along with the main power lines to the T-stat.
How did you switch the fan? The fan is also an inductive load, which could cause a voltage spike on the 12V line when it does not have a reverse current protection diode in parallel.
I think that would be more likely than the AC induction breaking anything.
If you put 12V on the wrong pin on the RJ12 block, this could also damage the controller.
I’m not switching a fan motor. The fan in the refrigerator runs constantly. The cooling fan on the control box also runs continuously.
I have however shortened several of the temperature sensors…successfully??? and was in the process of doing so for the fridge chamber temp when the issue appeared to have occurred. Perhaps that is the cause.
When the new unit arrives I will start up with one of the original sensors.
Is there a way to verify that this was the issue? Can I measure resistances across the RJ12 pins on the temperature sensor?
Thanks for the input.
When you are wiring your own sensors, never connect 12V until you are sure that everything is connected correctly. Only power the BrewPi Spark from USB.
If you are lucky, only the photon is damaged. If you are unlucky, the OneWire chip needs to be replaced.
As long as you do not connect 12V, there is not much risk in connecting sensors wrong. You’ll only damage the sensor.
You cannot measure resistance of the DS18B20 sensors. Don’t trust any sensor that got hot.