A:AnswerAloha.
Short answer: your Panamax 5400PM is operating as expected and should be 100% fine. I have 2 identical units for my system and they both work wonderfully and have for quite some time. I’ve owned Panamax units for the last 15 years and have found them to be very reliable and high quality builds.
I’m not sure where you are located, but based on your reference to 120 volts, I’ll assume for purposes of my response that you are in the US...most countries deliver “full” three phase power service to homes between 380 to 480 volts at either 50 hertz or 60 hertz frequencies. However, most standard outlets deliver power at 1/2 this voltage based on the wiring configuration (hot vs neutral). In the US for example most residential customers will receive 120 volts from standard wall outlets. However, power is delivered to US homes at a nominal voltage of 240 volts. Inside the transformer on the utility pole, the power is divided into a split phase system, with each line having a nominal voltage of 120 volts. Nominal voltage is the voltage that the line is designed for; however, the tolerance for voltage fluctuations is −5% to +5%. This yields an actual voltage range between 114V to 126V from your outlet and a voltage range of 228V to 252V for your full-phase appliances. So, an incoming voltage reading of 122 is well within the expected tolerance limits for electrical service and most every electrical device you would connect to it.
Your 5400 regulates voltage in discrete steps. So instead of 122 in, 120 out, you will see 122 in, 122 out. When the incoming voltage exceeds that 1st step, then the regulation transformer knocks it back down approx 10v each step. IIRC, 124-125v is the 1st step where it kicks in so if it's ~125 in, it'll be 115 out. Given a plus-minus volt meter display slop factor, this is what yours is doing.
Below is a link to a review from yrs ago that explains this far better than the manual and provides a graph showing each discrete step, the voltage that triggers it, and the resulting voltage decrease.
http://www.laaudiofile.com/max5400pm.html
I hope this answers your question and best wishes / happy listening and watching.
Thanks to the wonderful folks on AVSForum for the helpful information provided above.
A:AnswerI asked this to two different electricians. They both gave me the same answer after about five years these protectors need to be replaced overtime they take little hits and if they get a big hit they are usually done. I looked it up online also and found the same thing.