Oberheim OB-Xa -1981    Weight = 45? Lbs. Number manufactured = ? MSR = $5995 (4646 ad price 8vc, subtract 450 per 2voices)

User Manual: Lazy Octopus
Reset Proceedures: N/A
Operating System code: Lazy blue Octopus
MIDI or other control protocol: N/A
Software related Links: N/A
Patches or knob settings: zicweb
Circuit Overview: below
Scematics/Service Manual: Lazy Octopus
Common Service Issues/Tips: below
Parts Sources: Keys knobs semiconductors misc
Uncommon chips/modules used:CEM3360 dual VCA, CEM 3340 VCO, CEM3320 VCF and CEM 3310 EG
Modifications:Analog diehard
General Info Links: Vintage Synth Explorer

Circuit Overview:
     Analog subtractive similar to OBX in some ways but condensed circuitry using the Curtis chips.

Service Tips:
     As with OB-8 I assume there are likely problems that can happen in the digital realm. VCO chips fail sometimes. There is a mod that should be performed to prevent DAC output voltages from causing issues with 4051 mux chips. Check out this great resources done by Analog diehard

Aside from some of the Curtis chips and maybe CPU I stock everything all the time electronically. I've gotten the chips when needed from other techs or off ebay. Knobs may be difficult to find exact replacement. The CEM3340 has been reproduced (Contact susanonchip@covad.net for details. Reasonable price but I hear for now at least pins are a bit weaker on them). The switches are available from analogdiehard@att.net I hear.
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