Classe DR-6 MM circuit L channel out, MC works

My Classe DR-6 high gain phono MM circuit has the L channel out, however the low gain MC circuit works fine. Before I tear into the thing I was wondering if anyone has worked out a circuit diagram. Perhaps there's a phono input impedance balancing card or such which might be loose or a history of bad input jacks???

Everything works fine on the low gain for phono, and everything else is fine too. Just wishing to get both channels of the high gain MM stage working so I can use a Benz Micro or such instead of the Sumiko Blue Point I currently have.

I emailed Classe for help, a schematic or test points or circuit description, but they wrote back a one sentence saying that they don't give out schematics. No other info, no suggestions, no "sorry it's broke".

So with little help coming from that source I was hoping audiogon might have that experienced someone who could help me. If anyone out there has worked through one of these Classe DR-6 high gain MM phono circuits and might be able to give me a few clues, let me know. Obviously with 1 side working I should be able to swap components. But I'd rather use my scope to trace the signal and find the bad connection or bad component that way.

I believe that when this preamp was sold it had a Lifetime warrantee.I know that my DR4 did and that was around'90. You may not be the orig. owner and they probably would use that to weasel out of the deal.
Hifiharv, you are correct, the DR-6 was sold with a lifetime warranty to the original purchaser only. It sounds like a solder joint has failed on the MM circuit. A local reputable repair shop should be able to source your problem.
Yes, I think it is probably not a blown input amp transitor but more likely a bad solder joint. I've got the function generator, the oscilloscope and the soldering iron. Also have years experience in Aerospace design engineering. I can probably poke around and find the problem.

I'm surprised at Classe's policy of "no information" for the owners of the products. Most audio products I've owned have come with, at the very least, a schematic and often a parts list as well.

Anyhow, if some of you Classe DR-6 owners out there have had this problem and know the circuit weak spots, let me know.

Your sage advice is appreciated.