Vsx-21 • Read online or download PDF • Pioneer VSX-21 User Manual. Browse manuals in p/pioneer/pioneer-vsx/pioneer-vsx-21/. Read directly or download PDF. No login, no charge and no limit.Find the user manual you need for your audio device and more at ManualsOnline. Pioneer VSX-21 Stereo System User Manual. Click on the link for free download! Document preview [2nd page]. PIONEER VSX-21TXH 23TXH 9040TXH 9140TXH service manual (2nd page) Preview of PIONEER VSX See Operating other Pioneer components with this unit's sensor on page 35. 16 Remote input(s)/output (x3 (VSX-23TXH)/x2 (VSX-. 21TXH)).