Hi,
as for my first post here, maybe I could be of some help with this issue...
I have had a similar problem with the very deck...a few years ago I bought it for my daughter's B&O system as a faulty unit. The seller (former B&O authorized serviceman) claimed it was broken, actually the cartridge needed replacment. The symptoms were much alike these you have described. Every other aspect of the unit was perfect.
So the idea was (the price I have paid was rather symbolic, since known issues about cost and ability of getting the new cartridge) to try to modify the tonearm and equip it with some others brand cartridge (mods of this kind can be found over the net, and some of them seemed quite atractive!).
Anyway, I've got the deck and asked a friend of mine to make an inspection before modification we agreed about. The guy is, btw, a true hi-fi genius and after listening just about ten seconds of distorted sound coming from the vinyl, he said it was definitly not the cartridge problem...checked the stylus under the microscope- 98% o.k.- and than opened the deck...
...it was RIAA amplifier one chanel ''something'' broken, and some capacitors etc...he has fixed it in 5 minutes and, voila, MMC2 was singing full bodied!
Next step was to remove RIAA amp completely since we have realized that the built in my daughter's Beocenter 9000 RIAA was much better constructed and sounding.
The deck plays flawlesly since, and spectaculary remotely driven via Beolink 1000!
So before going for new cartridge, please check other solutions, maybe it helps!
Best rgeards,
G