After the above activity, I received an email from Greg, saying amongst other things:
I reckon you have fixed the crazy organist that plays 24-7. He was quiet first thing this morning and by 6pm the speaker was just buzzing but no music.
Since that wasn't the reason that I went in, I was intrigued at this, but thought bothing more of it.
Today, I went in to do some River System testing and Greg said that the audio in the Minster was stuttering. When I investigated, I found that the MP3 audio was restarting, just like it had been last year before I fitted the fan. After this was fitted we had two issues; the original PSU brick failed and the fan became sticky. When I fitted new devices the hum from the system became unacceptable, so I built some audio filers and slowed the fan down using a series resistor (see
https://wmtprojectsforum.altervista.org ... t=10#p1014). Now it seems that i may have slowed the fan too much!
As a temporary fix today, I shut down the system for a few minutes to allow it to cool. I then opened the case and left the access door open (it is tied with string). I'm hoping that this additional airflow will allow the Pi to run much cooler.
If this appears to work, then I will remove the system from it's case and drill some holes in the bottom and back of the case to allow a reasonable airflow. I will then remove the fan and re-install the system with the case standing on runners to allow the air into the case to come in and get out after having gone over the heat-sink.
We will then monitor the situation over the summer.
One thing. We chose the ammo box solution for the case, because at the time it was cheaper than the IP65 cases then available and the Minster tended to get damp. The heat inside the case should be able to disspate the moisture while the system is running, but we will need to ensure that the box is removed after Winter Shutdown.