I recently purchased a Frankenstein and had the same issue. The answer I got when asking the same question was that when you first turn on the machine and only get half of frank... is completely normal and all sega and data east machines do that. It should only happen at start up. If the sound is resetting while playing then you have a different issue. I had the display resetting which might have caused certain sounds from happening at the time of reset, but not sure about that. I fixed the problem by ordering a new dmd power cable from Marco. The new cable is intended to fix the power problem and sega issued a service bulletin with the installation procedure.