Every one of my MOXFs (three MOXF6s and one MOXF8) have displayed the exact same problems. This can't be a coincidence.
When I'm working in Song mode, every once in a while, the volume of one (or more part/tracks) will SUDDENLY spike to an earblasting volume. It is always a track I'm NOT working on at the moment.
Every MOXF has episodes when the transport system stops responding correctly. Turn the data wheel and nothing moves. Use the buttons under the data wheel, nothing. Try to use a transport button to jump back in increments. Nothing. Or it responds in super slow motion, taking several seconds to do what would ordinarily be "real time" selection or scrolling.
I've tried stopping and doing a Store, in case the processing buffer is overloaded. It makes no difference. I know the pace and rhythm of the sequencer in these synths and it is most certainly not correct. Sometimes I'll just struggle along and put up with it, other times I have to just walk away. Turn it off, wait a few hours, and it might be back running as it should.
Of my four MOXFs, two of them were purchased new, in the box, from Guitar Center (in March 2020) and Sweetwater (May 2021). The brand new MOXF8 immediately began doing the same things my two older ones were doing! Sudden volume spikes, sluggish, unresponsive transport. I had it brought immediately to a Yamaha authorized technician in Durham, NC who could find nothing wrong, and when he attempted to get some guidance from Yamaha in California, the tech rep there expressed surprise and disbelief that the keyboard was actually new merchandise and that I might be sh** out of luck because the parts are no longer manufactured! Things got testy I understand and I'm not sure what was done or not done, since I had to leave the keyboard behind when I left the country.
So, what do I do? I had no choice but to purchase ANOTHER MOXF, brand new, in the box (yes, Yamaha, CA, brand new!) from Sweetwater and had it shipped at no small expense to me in Belize, where I reside most of the year and make my living playing music.
Since neither of my first two MOXFs could be relied on -- the volume spiking could occur in any scenario, including a live gig -- once I had the MOXF6 from Sweetwater I decided to send the two older ones to the Yamaha service in Mexico City. They ran the diagnostics and, nope. Can't find anything wrong with either keyboard.
So, now...... you guessed it. My brand new MOXF6 is doing THE SAME THINGS. Exactly. Spiking, sluggish or unresponsive transport.
This is clearly a REAL glitch in the MOXF synth. With four keyboards, it ain't my imagination. So now I have yet ANOTHER MOXF, barely 6 months old, under warranty that I have no idea what to do with, or how to get any satisfaction from Yamaha.
At this point, with the MOXF discontinued, I'm simply trying to keep body and soul together as a working musician. I cannot believe I am the only person who has experienced these problems. But even if so, I feel like my decades long loyalty to Yamaha products has gone unrewarded.