The on/off cycling problems were addressed many years ago when computer manufacturers began using activation and shutdown delay powering devices, thereby sequentially turning on and off the device. This same technology is used with a myriad of electronic devices, including cell phones, arranger keyboards and amps. Consequently, turning the device on and off no longer has the same detrimental effects as it did in the past.

The big killers of sound system, IMO, is overloading them and the lack of cooling fans. Donny Pesce experienced this with the old models of Barbetta Sona 32SC that he owned. When they got hot, they would actually trip the safety cutoff thermister, which shut down entirely until it reached a safe operating temperature. I solved his problem by installing cooling fans inside the cabinets and placed vents in them as well.

Many years ago, I had two amps trashed by cigarette smoke in the American Legion where I performed every Friday night. The smoke was so thick when someone opened the entrance door, folks outside would think the building was on fire when the smoke rushed out the door. Every plug, jack and switch inside that fan cooled powered mixer/amp was completely covered with cigarette tars in less than 6 months of use.

High humidity will destroy PA systems during outdoor jobs. When very moist air is drawn into the system via the cooling fan, it can readily condense on the PC boards especially if the PA is fired up right after being removed from an air conditioned vehicle and set up in that warm, moist environment. Best to allow the PA temperature to equalize with the surrounding environment before turning it on.

When not in use, it's always a good idea to cover the PA with some type of cover to prevent dust and moisture from entering the system. Same is true with your arranger keyboard.

Hope this helps,

Gary