What am i missing here? Why are you using a variac? Why are you setting the voltage to 89 volts? Is this standard procedure with Joule products?
Out of curiosity, what is your standard line voltage? When it fluctuates, how far up and down does it vary? If there is a big swing in voltage, you may need to contact your power provider and have them assess the situation.
As a side note, i just went through this at my shop last summer. The voltage used to hover right around 118 but was sagging down to 104 at times. A new business just opened up and they had a machine that would pull 400+ amps at turn on. Needless to say, every time that they turned it on, the voltage would bottom out. After calling the power company and providing them with detailed reports, they replaced the pole transformer. All has been good since then. Only problem is that the voltage is now up around 125 volts all the time, which is a bit on the high side.
Same thing was happening here at my home a few weeks ago. When watching a movie on my HT system, my Pre-Pro started glitching and the lights on the amps were flickering during loud passages. On the next loud passage, the lights in another room started to blink. This told me that there was a problem with either the AC mains in my house or the power provider was having problems.
Not wanting to expose all of my equipment to potential damage, I ran downstairs and shut down the box feeding the AV systems. I then went to see if the neighbor was having problems or if it was just in my house. While walking over to the neighbors house, i saw that the AC pole transformer feeding my house was on fire. Needless to say, i ran back in and called my power provider and the fire department.
Believe it or not, they came out and repaired the problem in a matter of less than 45 minutes. Since then, my AC has been much more consistent and noticeably quieter.
Sorry to go so far off topic, but given my past experiences, you might be in a similar situation. You might want to monitor your AC and keep a log. The more documented info that you can provide for your power company, the more likely you are to get results.
In case you didn't know, the Monster AVS2000 produces audible clicking sounds during normal operation. I'm not familiar with the ExactPower unit. Sean
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