MATRIXSYNTH: Oberheim OB-8 SN C34903

Monday, December 07, 2020

Oberheim OB-8 SN C34903

via this auction

"Oberheim OB-8 in beautiful cosmetic condition, fully serviced, calibrated and fully functional. One of the nicest OB-8s in the market at the moment. The front panel is very clean with very minor scratches. Please refer to the posted pictures. I zoomed in as much as possible to highlight those scratches. These scratches are less visible on the actual unit. The original wooden end cheeks are also very clean as can be seen in the posted picture.

This OB-8 has is serviced by one of the best techs in Alberta, Canada as of December 2020. Here is the list of the works done on this OB-8:

• All capacitors and bridge
rectifiers are replaced by high quality ones from Synthchaser's “Power Supply Capacitor & Rebuild” kit.
• All capacitors and fixed resistors are replaced with high quality ones from Synthchaser's “Voice Board Ultimate Service” kit.
• Two faulty CEM3310 filter envelope chips on voices 1 and 3 (U111 and U311) are replaced.
• Two faulty CEM3340 VCO chips are replaced with the new CEM3340 Rev G chips on voices 1 and 3.
• Soldered-in battery are replaced with a 2xAAA holder, into which Energizer Ultimate Lithium cells were inserted. A silicon diode (1N4148) was inserted in series with batteries to drop appropriate voltage. Holder mounted within easy reach upon cover removal.
• The following trimpots are adjusted (on all voices where applicable): oscillator 1 V/oct., oscillator 2 V/oct., filter envelope modulation, filter resonance, filter V/oct., filter initial frequency, and lower voice board output level.
• Power supply voltage trimpots T1 and T2 are adjusted.
• All control potentiometers are cleaned to fix scratchiness/intermittency on several controls.
• The MIDI functionality is tested
and the unit receives, transmits, and passes through MIDI data normally.
• All the trimmer are adjusted. No problems whatsoever with the existing trimmers.
• All voice panpots are
• DAC and bend lever calibration are checked.
• All LEDs are Checked.
• The unit is calibrated according to the factory manual."

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