I acquired 6 of this amplifier. I vacuumed out dust, lubricated fans, checked caps and replaced a few on 2 amps. All other parts, transistors, etc are all original and all amps appear to have never been serviced. Tested into 5 ohm loads with 1KHZ sine wave to full power. These amps guaranteed to be working perfect. Cosmetics vary, with all having some scratches.