Mid-century vintage, vacuum tube ITT SMX-500 stereophonic AM-FM tuner/amp

Vintage ITT model "SMX-500A AM-FM MPX Stereophonic Tuner Amplifier" with the original manual. The manual has about 7 pages. We plugged this unit in and it powers up and the tubes glow. This looks in good condition, but we don't know much about it and so we're selling it for restoration or parts.