Info

Check the +5M (+5 MEMORY) on the right lead of D4 located at the middle top of the processor board. With power ON 4.4v - 600 mv (3.80v to 5.00v) With power OFF 2.7v 1.3v - 300 mv (2.40v to 4.00v) 4. Set the DVM for DC volt, range lOOv. Check the 55v on pin 6 of the power connector of the pot board 5. Set the DVM for AC volt, range lOv. Check the 9v AC between pin 7 and 8 of the power connector on the pot board. NOTE The AC frequency at this point is approximately 30 KHz. Make sure that your AC...

Ram 0 Ok Ram I Ok Ram 2 Ok Rom 0 Ok Rom 1 Ok Rom 2 Ok Rom 3 Ok

If one of the test fails (RAM or ROM X BAD) replace the corresponding Chip. RAM 0 U2, RAM t U3, RAM2 r U4, ROM 0 U8, ROM I U7, ROM 2 U6, ROM 3 U5. 5. Allow 20 seconds delay and check for message CA MEM OK. If the test fail (CA MEM BAD), replace successively U9I2, U914, U917 until the test run succesfully. 5. Check for all 16 LEDs lit for approximate 2 seconds. Check then for all LEDs lighting one after each other one at a time. 5. Check for all segments ON for all 120 digits. Check for all...

Analog To Digital Converter Calibration

Note This calibration is going to set the volt per octave of the CV in. It is assumed that the controlling CVs are in the range 0 to 5 volt, that they are set for 1 volt per octave * - .2 with a linearity of at least .1 and that the offset is no more than + - 15 mv. If the controlling device does not fulfill these requirements it will have to be corrected. A) DVM METHOD (calibration relative to Internal DVM reference) 1. Set the DVM for DC volt, range lOv 2. Attach the negative lead of the DVM...

10

The CEM 3372 is an audio signal processing device. It includes a two channel voltage controlled mixer, a dedicated 4-pole low pass VCF with voltage controlled resonance and a final VCA. With the exception of the filter cut-off frequency, all control inputs are very low bias current, high impedance which range from 0 to 5 volts. Reproduced with permission of Curtis Electromusic Specialities The Xpander voice allows dynamic linear modulation of VC01 frequency by VC02 triangle output. This is done...

Display

BR GHTNESS ADJUSTMENT 55v TEST POINT 3. Turn the three brightness trimmers all the way up (maximum 4. Turn down the trimers of the brightest displays to match the dimmest one. 1. Attach the negative lead of the DVM to the ground lug on the voice board at the left of the DAC. 2. Set the DVM for DC volt, range lOv. 3. With the positive probe check the 4 v reference voltage on pin 8 of U815 (TL084) in the DAC area of the voice board. 3.920v < 4v ref < 4.080v (4v - 2 ) 1. Set DVM for DC volt,...

Resonance Control On Sample And Hold

As the frequency ot the CEh 3372 changes slightly with its resonance setting, the VCF frequencies are automatically retuned after the resonance calibration has been performed. The CEM 3374 contains two completely independent precision voltage controlled oscillators. The 3374 includes an on-chip temperature sensor which generates an output voltage, nominally +2.5V, proportional to the chip temperature with a T.C. of +3300 ppm. Reproduced with permission of Curtis Electromusic Specialities

Alps

651860 XPANDER POT BOARD PCB ART 1861-1862 750189-0 CABLE SUB-ASSY OB-XPANDER 8 651860 XPANDER POT BOARD PCB ART 1861-1862 750189-0 CABLE SUB-ASSY OB-XPANDER 8 241012 V FLOURESCENT DISPLAY FG405A2 ITRON 3 476010 TRIMMER 10 K 375E103B CRMT 4 153013 CAP MYLAR FLM .1 .4LS 1 157021 CAP CER DIP . 1 MF 20' . 50V 1 217005 TERM FEED THR0UGH-025 PIN CONCORD 6 219512 CONN RIBBON 26P RIGHT ANGLE HEADER 1 219902 IC SOCKET 14 PIN ICY-143-S3 1 219903 IC SOCKET 16 PIN ICY-163-S3 8 219905 IC SOCKET 13 PIN 9...

Michel Doidic

REMOVE 12 I0K RESISTORS (RX62 AND RX78) AND REPLACE WITH 33K RESISTORS (478333). 7. REMOVE 10K RESISTOR CR186) AND REPLACE WITH 4. 7K RESISTOR (478472) IN NEW POSITION AS SHOWN. 6. REMOVE 12 I0K RESISTORS (RX62 AND RX78) AND REPLACE WITH 33K RESISTORS (478333). 7. REMOVE 10K RESISTOR CR186) AND REPLACE WITH 4. 7K RESISTOR (478472) IN NEW POSITION AS SHOWN.

Voice Schematic 1814 Sheet 3 4 Voice Parts Layout 1813b

AS REQUIRED IN TEST El FUTURE PRODUCTION RETROFIT PRODUCTION AND INVENTORY RETROFIT IN FIELD DAS NEEDED REMOVE DISTORTION IN VOICE'S FINAL YCA, AND DECREASE VCA BYPASSING. 1. CLEAN ANY SOLDER FROM WITHIN SELECTED FEEDTHRUS ON ALL SIX VOICES. 2. MAKE 12 CUTS AS SHOWN TO MOVE TRACE FROM ORIGINAL POSITION. 3. FROM BACK OF BOARD SOLDER JUMPER TO FEEDTHRJ. THEN ROUTE AS SHOWN. 4. SOLDER OTHER END OF JUMPER TO 8ACK SIDE OF BOARD.

Vco And Vcf Frfoufncy Tuning

The volts per octave scaling parameters of the Xpander's 12 VCOs are adjusted by the voice microprocessor whenever the VCO function is selected in the tune page. By using the timer U921, the microprocessor mesures successively the five following frequencies C4, E5, 6 6, C8, E9 for each VCO, and calculates the proper correction voltages to bring each oscillator in tune These correction values are stored in the main processor's battery back up memory for instant recall upon power on. During...

Ct

OBERHEIM PART NUMBER CROSS REFERENCE PROCESSOR BOARD 219029 DIN ISO DEGREES 5 PINS PCMT 3 281066 SCREW 2X1 4 PPSMS BLUNT PHIL PAN 6 239019 CABLE TIE 4 OVERALL LENGTH T13R 1 310007 XP1.0-0 XPANDER 2764 XP 1.0-0 1 310007 XP1.O-1 XPANDER 2764 XP 1.0-1 1 310007 XP1 0 2 XPANDER 2764 XP 1.0-2 1 310007-XP1.0-3 XPANER 2764 XP 1.0-3 1 316003 MICROPROCESSOR 6SB09 3-BIT 1 317014 RAM 6264 8K CMOS RAM 3 318007 AC IA SERIAL INTERFACE IC MC68B50P 1 318008 OPTICAL IC PHQTOCOUPLER HP 6N138 1 401002 BATTERY 2.9V...

Oberheim 561023

478623 RESISTOR FXD 1 4W 2-57. 62 K 6 478631 RESISTOR FXD 1 4W 2-57. 680 OHM 13 478633 RESISTOR FXD 1 4W 2-57. 68 K 6 479003 RESISTOR NETWORK 4.7K SIP 10 PIN 3 479007 RESISTOR NETWORK 4.7K SIP 8 PIN 10 431001 DIODE SIGNAL 1N4148 34 482017 DIODE ZENER 6.9V LM329CZ 1 435003 TRANSISTOR SS NPN MPS5172 1 151024 CAP ALUM ELECT 15 25V RADIAL 151037 CAP ALUM ELECT 10000MF16V AXIAL 151041 CAP ALUM ELECT 22 100V RADIAL ESR 151042 CAP ALUM ELECT 100 25V RADIAL ESR 151043 CAP ALUM ELECT 1000 10V RADIAL ESR...

Voice Board

310007-CA1.0-0 XPANDER 2764 CA 1.0-0 1 310007 CAi.0 1 XPANDER 2764 CA 1.0-1 1 311039 IC 74LS273 OCTAL D-TYPE FLIP-FLOP 1 311043 IC 74HC374 HI-SPEED CMOS OCTAL D 6 315043 IC 7523 AD OR MP 8-BIT DAC 6 316003 MICROPROCESSOR 68B09 3-BIT 1 317014 RAM 6264 3K CMOS RAM 1 318004 8253-5 PROGRAMMABLE INTERVAL TIMER 1 313005 14 BIT DAC HYBRI HS3140C-4 MP7614KN 1 319009 AUDIO SIGNAL PROCESSOR CEM-3372 6 319010 DUAL VCO CEM-3374 6 476011 TRIMMER 100 K 375E104B CRMT 1 151024 CAP ALUM ELECT 15 25V RADIAL 34...

Xpander Circuitry Overview

Point Dual Fluorescent Display

The key to the outstanding performance and features of the Xpander is the intensive use made of its two built-in microprocessors. The first microprocessor is called the main processor and is located on the processor board. Its main tasks are Collecting and processing information coming from the front panel controllers encoders and switches . Collecting and processing information coming from the outside of the Xpander through MIDI or control input jacks CVs and GATES, PEDAL etc. . Controlling...

Xpander Service Manual

Oberheim Xpander Diagram

A Division of ECC Development Corporation 11650 W. Olympic Blvd., Los Angeles, CA 90064 The design philosophy behind he Xpander was to include all the features of a modular synthesizer in a programmable and easy to use instrument. At the same time, reliability, accuracy, and ease of servicing have been a prime concern through every step of the design. The result is the most complete and accurate analog polyphonic synthesizer ever built, despite the inclusion of 6 trimmers. Besides the...