Control24 Intermittent Hiss in Monitor

[Rwave]

Hello all,

I've had a Control 24 in my studio for the last 4-5 years. About 2 years ago the power supply that the unit shipped with died, and I installed a new one. Since then, occurring at completely random intervals and times, I get a slight hiss coming out of my left Genelec monitor. Adjusting the monitor controls on the Control 24 has absolutely no effect (Main Monitor Level, PT sources, Ext sources, Mute All, etc).

When I first experienced this problem, I thought I may not have fitted and glued all the connectors from the power supply as thoroughly as I needed to. I went back and re-installed it... re-cleaning all connectors with DeoxIT and making sure everything was reconnected and glued as securely as possible. After doing this, I didn't experience any problems for a good 6-8 months.

When the hiss came back, I found power cycling the Control 24 to be a quick, temporary fix, usually lasting at least 24 hours. I also found that touching random parts of the back panel or any cables plugged into it will have an effect on the hiss. This has me wondering if it might be a grounding issue or something related to it.

Has anyone ever experienced anything like this? Any thoughts or theories on what this may be and how best I could solve this problem permanently?

Thanks in advance for any help!

Jason