The Oberheim OB-Xa is a programmable polyphonic synthesizer renowned for its powerful sound engine and distinctive sonic character. This standalone model, while vintage, offers robust performance with its dual-oscillator voice architecture, featuring sawtooth, pulse, and square waveforms, and a 2-pole voltage-controlled low-pass filter. It provides 6 or 8 voice polyphony, ADSR envelopes, LFO modulation, and a 5-octave keyboard. Notable for its potential chorus effect, the OB-Xa is a celebrated instrument for musicians and sound designers seeking its unique analog sound.

This service manual provides comprehensive guidance for the maintenance and repair of the Oberheim OB-Xa. It covers essential technical specifications, common troubleshooting procedures for issues such as component drift and power supply instability, and detailed calibration steps for oscillators and filters. The manual also includes information on key components, repair tips requiring soldering skills, and crucial electrical safety warnings regarding high voltages. This resource is designed to assist owners, technicians, and enthusiasts in preserving the optimal functionality and sonic integrity of their OB-Xa.