NCook mibht be right about the speaker, OR maybe it is four ohms ? Newer stuff (you call that vintage but I don't) really don't like pfour ohm speakers.

Could also just be a weak point in the design.


Closest print I could get was for a 518 which may or may not be the same. It shos discrete component output stages but the scan is so ****ty I can't tell much else about it. But at least it doesn't use ICs that you might not be able to get. Just got through with onr like that I had to slightly redesign for a guy in Pittsburg. Damn shame all the money he has into that unit but he figured it was worth it. Redesigning is not cheap.

But IF it is discrete component it is just a matter of a few transistors, maybe resistors. While I don't call that model vintage, it is probably worth fixing.

Or you could just take some eight ohm resistors from right and left and feed the center from them. That is almost what the amp does in most normal modes, but it does it at line level. Phantom and some other modes don't, but I don't know about you, I think L+R should be sent to the center channel. That way you might be abl to understand the dialogue in a movie amidst all the %^#$$# special effects. It would work for now whilst you get one of them fixed.