Arp odyssey service manual

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ARIPOYSSEY

SERVICE MANUAL

MODELS 2800 THROUGH 2823

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SECTION 1

1.1 Introduction

This service manual is divided into three major
sections: A) Circuit Descriptions, 8) Trim Pro-
cedures, and C) Board Test Points. The circuit
descriptions should be consulted when a problem is
suspected in a particular area of the instrument.
The trim procedures should be used to verify cali-
brations or when a component has been changed.
The board test points are a quick reference to verify
circuits with suspected problems and should be
checked whenever a problem has been identified.

1.2 Board Identification

Three types of Odyssey models have been produced:
I) 2800, 2) 28102815 and 3) 2820-2823. The model
and serial number are located at the rear or bottom
of the Odyssey chassis. Except for 2800, a typical
number might read: 2813-0490. For model 2800,
the first two digits of the serial number denote the
model, such as: 28490. Listed below are the board
identification numbers for each model; they will be
referenced in the service manual by model number
for easy identification.

ODYSSEY~I
Model 2800
Board: A-1
8-1
01
PWR SUP-1
ODYSSEY-ll '

Modei 2810-2813 Model 28202823

Board: All Board: All (With PPC) '
8 8-
0 Oil
PWR SUP~ll PWR SUP-ll

Note: Some Odyssey-2 mode/s employ the older
style Board 8-].

1.3 Model Changes

The Odyssey has undergone major cosmetic and
electrical changes since its original production in
1972, however, the functional capabilities have
remained virtuaily unchanged. The following are
the most noticeable physical differences among
models:

PRELIMINARY INFORMATION

MODEL 2800

Black and white face panel (some later models
have black and gold face paneis).

Pitch Bend knob

No Factory installed interface jacks.

Wrap around vinyl bottom cover.

MODEL 2810-2813

Black and gold face panel.
New style power switch.
Factory installed interface jacks;

Pitch Bend knob. (Some later models have
PPC.)

Wrap around vinyl bottom cover.
MODEL 28202823 (current model, Odyssey 78)

Black and orange face panel:
Steel chassis

Leather endblocks
PPC

The major electrical changes found in the Odyssey-4| r
as compared to the Odyssey-l are:

1- U585 24db/octave filter in place of 12db/i?

octave.

2. Improved VCO design for better trackingi
and stability.

3. improved power supply regulation.

4. Improved keyboard current source for CV

generation.
5. Improved S/H memory circuit design.

1.4 Revisions/Changes

1.4.1 MODIFICATION KiTS

The following modifications are available from the
Factory for updating older style Odysseys:

Modification For Model Kit No.

Interface Jacks 2800 6800101
PPC 2810-2815 6800301
PPC 2800 6800501

1.4.2 KEYBOARD CONVERSION

The Odyssey-ll is designed to be used with a two bus
keyboard. When an Odyssey-ll is used with a three
bus keyboard, an interface board is inserted on the
molex pins on Board A-ll to make the keyboard
compatible with the electronics. Illustrated below