Game has basically played and worked fine the short time since I've owned it. But now during early game play it will deteriorate into garble, low volume and "crosstalk" of tunes and speech. I get a "music failure ID 00 567 L6" message. I checked the MPU and found hand-written labels on 1 & 2 L-6 ROMS: suspect clues of replacements? Is this where I should start? I read past posting history on this failure code but could find no definitive solutions. I found a used L-6 set on ebay, but is that a good idea and will that address the issue? This newbie has no idea. Would be appreciate any advice.