Dear all,
I know this is an old thread but just wanted to share my experience maybe it will help somebody.
I bought AR-90 a few days ago... one tweeter worked occasionally and when it worked I could hear it works on lower volume. First I thought it must be the crossover and the switches on the back. Well to keep it short it wasn't. When I took out the tweeter it showed a dc resistance of 80ohms, then 2kohms, then 50 ohms etc when poked on the metal parts for wires... I thought it was some oxidation but actually it was bad solder between the speaker coil wires and the metal parts (i do not know the english word for it, its on the picture). Resolder it, got normal 4.7 ohms and the tweeter works fine.
