Place them equidistant from your main listening position, angled slightly inward.
If your system behaves erratically, consult this quick reference checklist derived from standard Sanyo engineering schematics. No Sound / Low Volume
This is the go-to repository for vintage audio schematics. You need to register (free), but the quality is unmatched. Search for "Sanyo DC-T990." They usually host the Owner's Manual and the Service Manual (which includes circuit boards and voltage readings). Manual Home Theater Sanyo Dc T990 pdf
Clean the metal heads gently using a cotton swab dipped in 90%+ Isopropyl Alcohol. Dust in the volume potentiometer
"Get the Most Out of Your Sanyo DC T990 Home Theater System: Download the Manual PDF" Place them equidistant from your main listening position,
The manual provides detailed operating instructions for the Sanyo DC T990, including:
A common issue without the manual: The system has a switch. If it is pressed in, you will get no sound from CD, Tuner, or Aux, even if the display lights up. Before assuming the amp is dead, toggle the Tape Monitor button on the front panel. You need to register (free), but the quality is unmatched
If you're unable to find a PDF manual, you can try: