I have an AU 217 too. Three years ago, I replaced all the Caps with Nichicon, Panasonic and WIMA (for caps upto 10uF). The fusing resistors & trimpots were also replaced. Bias reset. The amplifier sounded much better after this. Two years ago, I replaced ALL the resistors with 1% metal film resistors. The sound quality improved signifcantly again. AM very happy with the amplifier. It plays a few hours every day and dosen't miss a beat. You won't regret restoring this little workhorse of an amp. Have fun.