Alesis ADAT BRC User manual

BRC SERVICE MANUAL
January 1, 1994
Revision 2.00

PREFACE
This document is intended to assist the service technician in the operation, maintenance and repair of
the BRC master remote control. This unit represents one of the building blocks of the complete ADAT
system. Together with the BRC Reference Manual, this document provides a complete description of the
functionality and serviceability of the BRC. Any comments or suggestions you may have pertaining to
the document are welcome and encouraged.
WARNINGS
TO REDUCE THE RISK OF ELECTRIC SHOCK OR FIRE, DO NOT EXPOSE THIS
PRODUCT TO WATER OR MOISTURE.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
The arrowhead symbol on a lightning flash inside a triangle is intended to alert the user to
the presence of un-insulated "dangerous voltage" within the enclosed product which may
be of sufficient magnitude to constitute a risk of electric shock to persons.
The exclamation point inside a triangle is intended to alert the user to the presence of
important operating, maintenance and servicing instructions in the literature which
accompanies the product.
REPAIR BY ANY PERSON OR ENTITY OTHER THAN AN AUTHORIZED ALESIS
SERVICE CENTER WILL VOID THE ALESIS WARRANTY.
PROVISION OF THIS MANUAL DOES NOT AUTHORIZE THE RECIPIENT TO COMPETE
WITH ANY ALESIS DISTRIBUTOR OR AUTHORIZED REPAIR SERVICE CENTER IN THE
PROVISION OF REPAIR SERVICES OR TO BE OR MAKE REPAIRS AS AN AUTHORIZED
SERVICE CENTER.
ALL REPAIRS DONE BY ANY ENTITY OTHER THAN AN AUTHORIZED ALESIS
SERVICE CENTER SHALL BE SOLELY THE RESPONSIBILITY OF THAT ENTITY, AND
ALESIS SHALL HAVE NO LIABILITY TO THAT ENTITY OR TO ANY OTHER PARTY
FOR ANY REPAIRS BY THAT ENTITY.
i

SAFETY SUGGESTIONS
Carefully read the applicable items of the operating instructions and these safety suggestions before
using this product. Use extra care to follow the warnings written on the product itself and in the
operating instructions. Keep the operating instructions and safety suggestions for reference in the future.
1. Power Source. The product should only be connected to a power supply which is described either in the operating
instructions or in markings on the product.
2. Power Cord Protection. AC power supply cords should be placed such that no one is likely to step on the cords and such
that nothing will be placed on or against them.
3. Grounding the Plug. This product has a 3-wire grounding type of plug (a plug with a grounding pin) for safety purposes.
This plug can only be used in a grounding power outlet. If the plug does not insert into the outlet you are using, the outlet
probably is not a grounding type of power outlet. Contact your electrician to replace the obsolete outlet with a grounding
type of outlet instead of defeating the safety feature of the grounding type of plug.
4. Periods of Non-use. If the product is not used for any significant period of time, the product's AC power supply cord
should be unplugged from the AC outlet.
5. Foreign Objects and Liquids. Take care not to allow liquids to spill or objects to fall into any openings of the product.
6. Water or Moisture. The product should not be used near any water or in moisture.
7. Heat. Do not place the product near heat sources such as stoves, heat registers, radiators or other heat producing
equipment.
8. Ventilation. When installing the product, make sure that the product has adequate ventilation. Improperly ventilating the
product may cause overheating, which may damage the product.
9. Mounting. The product should only be used with a rack which the manufacturer recommends. The combination of the
product and rack should be moved carefully. Quick movements, excessive force or uneven surfaces may overturn the
combination which may damage the product and rack combination.
10. Cleaning. The product should only be cleaned as the manufacturer recommends.
11. Service. The user should only attempt the limited service or upkeep specifically described in the operating instructions
for the user. For any other service required, the product should be taken to an authorized service center as described in the
operating instructions.
12. Damage to the Product. Qualified service personnel should service the unit in certain situations including without
limitation when:
a. Liquid has spilled or objects have fallen into the product,
b. The product is exposed to water or excessive moisture,
c. The AC power supply plug or cord is damaged,
d. The product shows an inappropriate change in performance or does not operate normally, or
e. The enclosure of the product has been damaged.
ii

DOCUMENT REVISIONS
Revision 1 4/5/93 Original Issue
Revision 1.02a 6/3/93 Added information pertaining to troubleshooting as well
as additional hardware modifications to the Main PCB.
Revision 1.04 8/6/93 Added further information pertaining to troubleshooting
as well as additional hardware modifications to the Main
PCB. Updated BRC Software History
Revision 2.0 1/1/94 Revised entire manual. Added BRC QC Test Procedure.
Added BRC System Exclusive information.
iii

TABLE OF CONTENTS
PREFACE............................................................................................................i
WARNINGS........................................................................................................i
SAFETY SUGGESTIONS.................................................................................ii
DOCUMENT REVISIONS................................................................................iii
TABLE OF CONTENTS ...................................................................................iv
LIST OF FIGURES............................................................................................vi
LIST OF TABLES..............................................................................................vi
1.0 INTRODUCTION.........................................................................................1
1.1 Scope..............................................................................................................1
1.1.1 Document Conventions ..................................................................1
1.2 BRC Reference Manual.................................................................................1
1.3 BRC Error Messages .....................................................................................1
1.4 BRC Sync Cable Requirements.....................................................................2
1.5 List Of Abbreviations....................................................................................2
2.0 BRC BUILDING BLOCKS.........................................................................3
2.1 BRC Power Supply........................................................................................3
2.2 Front Panel PCBs...........................................................................................3
2.3 Main PCB ......................................................................................................3
2.3.1 VCO Circuit....................................................................................3
2.3.2 10 MHZ Timer................................................................................4
2.3.3 ADAT Synchronization..................................................................4
2.3.4 SMPTE Interface ...........................................................................4
2.3.5 Video Interface ...............................................................................5
2.3.6 48 KHZ Interface............................................................................5
2.3.7 MIDI Interface................................................................................5
2.3.8 Main PCB Component Orientation ................................................5
3.0 BRC REPAIR................................................................................................6
3.1 BRC Assembly and Disassembly..................................................................6
3.2 Removal of the Front Panel PCBs.................................................................6
3.3 BRC Internal Cabling....................................................................................8
3.4 Front Panel Troubleshooting .........................................................................8
3.4.1 Front Panel PCB LEDs...................................................................8
3.4.2 Front Panel PCB Switches..............................................................9
3.4.3 Orientation of the Diodes and the LEDs ........................................9
3.5 Main PCB Troubleshooting...........................................................................9
3.5.1 VCO Circuit Troubleshooting ........................................................11
3.6 BRC Software Upgrades................................................................................11
3.7 Error Messages ..............................................................................................11
iv

4.0 BRC TESTING .............................................................................................15
4.1 BRC Initialization..........................................................................................15
4.2 BRC Self Test Routines.................................................................................15
4.3 QC Test Procedure.........................................................................................17
5.0 BRC SYSTEM EXCLUSIVE INFORMATION.......................................18
5.1 Alesis BRC System Exclusive.......................................................................18
5.1.1 Opcodes ..........................................................................................18
5.1.2 Global Parameter Edit Commands .................................................18
5.1.3 Song Parameter Edit Commands....................................................20
5.1.4 Action Commands..........................................................................23
5.2 MIDI Machine Control Commands...............................................................25
5.3 Universal System Exclusive MIDI Inquiry Message....................................26
5.4 Software Level (v0 v1 r0 r1) .........................................................................26
APPENDIX A
BRC SCHEMATICS...........................................................................................A-1
APPENDIX B
BRC HARDWARE UPGRADES .......................................................................B-1
BRC Main PCB Upgrades.......................................................................B-2
Power Supply Insulator Sheet..................................................................B-4
APPENDIX C
BRC SOFTWARE HISTORY.............................................................................C-1
Version 1.00.............................................................................................C-2
Version 1.01.............................................................................................C-2
Version 1.02.............................................................................................C-3
Version 1.03.............................................................................................C-4
Version 1.04.............................................................................................C-4
APPENDIX D
BRC PARTS LIST ..............................................................................................D-1
APPENDIX E
BRC QC TEST PROCEDURE............................................................................E-1
1.0 Equipment Requirements...................................................................E-2
2.0 Visual Inspection...............................................................................E-2
3.0 BRC Connections and Setup .............................................................E-3
4.0 BRC Self Tests ..................................................................................E-5
5.0 Save Setup to Tape Test ....................................................................E-9
6.0 Load Setup from Tape Test ...............................................................E-10
7.0 BRC Loop Test..................................................................................E-10
8.0 BRC Auto Punch Test .......................................................................E-11
9.0 Additional Test Requirements...........................................................E-12
10.0 Digital I/O Test................................................................................E-13
11.0 Tape Offset Test ..............................................................................E-14
12.0 Preparation For Delivery .................................................................E-14
v

LIST OF FIGURES
Figure 3-1 - BRC Assembly and Disassembly....................................................7
Figure 3-2 - Diode Orientation Within the BRC.................................................9
Figure 3-3 - LED Orientation Within the BRC...................................................9
Figure 3-4 - Pinout Diagram of EPROM Chip (U9) ...........................................12
Figure 3-5 - Pinout Diagram of Processor Chip (U10) .......................................13
Figure 3-6 - Pinout Diagram of FPGA Chip (U11).............................................14
Figure B-1 - BRC Main PCB Jumpers................................................................B-3
Figure E-1 - BRC QC Test Connection Diagram................................................E-15
LIST OF TABLES
TABLE 3.1 - BRC RIBBON CABLE INTERCONNECTION ..........................8
TABLE 3.2 - SOFTWARE COMPATIBILITY CHART...................................12
TABLE 4.1 - BRC SELF TESTS........................................................................16
vi

1.0 INTRODUCTION
1.1 Scope
This service manual is intended to serve as a primer to assist repair technicians in isolating and
correcting problems associated with the BRC Master Remote Control. This service manual includes
PCB schematics, PCB comp. IDs., top side pin diagrams for the FPGA and Processor sockets, socket
diagrams for the 2 different types of EPROMs (see section 3.6 for explanation), System Exclusive
information and a description of the hardware operation of the BRC from a servicing point of view.
1.1.1 Document Conventions
Throughout this service manual, certain conventions are followed in order to make this manual
more coherent. LEDs and signal mnemonics are spelled with all capital letters (such as RECORD LED
and SLAVECLK) while BRC functions to be performed by the operator are spelled in bold capital
letters (such as PLAY or REWIND).
1.2 BRC Reference Manual
The BRC Reference Manual (Alesis P/N 7-51-1066) is included with every BRC sold. This
manual explains the basic operation, features, and applications of the BRC. The manual contains
diagrams of both the BRC front panel controls and the rear panel interface. Moreover, the manual
contains several connection diagrams for a variety of recording situations. Please refer to this manual
when information on the operation or connectivity of the BRC is required.
1.3 BRC Error Messages
Although the BRC's LCD display will indicate various erroneous conditions which may be
encountered during normal operation (see section 3.5), the BRC's LED display does not indicate any
BRC related error messages during normal operation. However, occasionally the BRC LED display will
indicate the message "Er On xx". In these cases, "xx" is the ID number of the ADAT where the error is
occurring. When this message is displayed, it is simply informing the operator that the ADAT in
question is performing error correction of the data being read off tape. This is a normal condition of the
BRC and should not be misconstrued as a problem with the BRC itself.
In situations where the above error message is consistently displayed, it may indicate a problem
with either the tape or the ADAT playing the tape. Making a copy of the tape in question may help in
identifying the exact cause of the error message. Refer to the BRC reference manual for more details on
making digital copies of ADAT tapes.
The BRC includes a self test mode of operation which is intended to aid the service technician in
the troubleshooting of BRC related problems as well as the verification of the units various functions.
Refer to section 4.2 for details on the self test mode of operation for the BRC.
Finally, BRC software version 1.04 contains a toggle which will deactivate the error message
indication on the BRC's LED display. Refer to the latest BRC reference manual for information on this
function.
1

1.4 BRC Sync Cable Requirements
The BRC was initially shipped with a 30 Ft sync cable which connected the BRC to the master
ADAT. However, this cable sometimes caused sync problems between the BRC and the master ADAT.
It was found that due to the cable's long length, its small wire gauge, and its lack of proper grounding
and shielding, "glitches" in the sync signal were being mis-interpreted by the ADAT. To remedy this
problem, Alesis now ships every BRC with a more robust sync cable.
The type of sync cable required for proper operation over long lengths must be a 9 wire cable
which is shielded and grounded at both ends. The 9 pin D-shell male connector pins at each end of the
cable are wired to the same signal. The wire gauge of these new sync cables is 24 AWG. To determine
which type of sync cable is the correct one, look at the cable's 9 pin connectors. If the word "Alesis" is
stamped on each side of both connectors, then it is of the correct variety. Moreover, if the cable is gray
in color and contains the "Alesis" stamp on the connector, it is also of the correct variety. However, if
the cable is black in color with no markings on the connector, or if the word "Alesis" is stamped on only
one side of each connector, then this cable must be replaced with the current cable (Alesis P/N 4-71-
0002).
For cable lengths less than 6 ft. (2 meters), any off-the-shelf 9 pin cable is acceptable for
connection between ADATs in a multiple ADAT system.
1.5 List Of Abbreviations
The following is a list of abbreviations to terms used throughout this service manual.
Abbreviation Definition Abbreviation Definition
A Amps (unit of current) LED Light Emitting Diode
AC Alternating Current LRC Little Remote Control
ADAT Alesis Digital Audio Tape MHz Mega Hertz (1,000,000 Hz)
ASIC Application Specific Integrated
Circuit MIDI Musical Instrument Digital Interface
AWG American Wire Gauge MMC MIDI Machine Code
BRC Big Remote Control MTC MIDI Time Code
CD Compact Disc OSC Oscillator
DAT Digital Audio Tape PCB Printed Circuit Board
dB Decibel PLCC Plastic Leaded Chip Carrier
DC Direct Current QC Quality Control
DRAM Dynamic Random Access
Memory RAM Random Access Memory
EMI Electromagnetic Interference RMB Remote Meter Bridge
EQ Equalization ROM Read Only Memory
EPROM Erasable Programmable Read
Only Memory SMPTE Society of Motion Picture and Television Engineers
ESD Electrostatic Sensitive Device SRAM Static Random Access Memory
FPGA Field Programmable Gate Array S/W Software
GND Ground µs Microseconds (1/1,000,000 sec)
H/W Hardware V Volt (unit of voltage)
Hz Hertz (unit of Frequency) VCO Voltage Controlled Oscillator
IC Integrated Circuit W Watt (unit of power)
2

2.0 BRC BUILDING BLOCKS
Within the BRC is a power supply, the Main PCB, and four Front Panel PCBs. The Main PCB
connects to the various Front Panel PCBs via ribbon cables. Each front panel PCB has its own name and
schematic (see Appendix A). The front panel PCBs are identified as follows: Left PCB, Right PCB,
Keypad PCB and 7-Segment PCB. A description of each BRC building block is presented in the
following sections
2.1 BRC Power Supply
The power supply is a switching power supply that outputs 5 VDC to the main PCB. A copy of
the schematic is provided in Appendix A. However, there are no serviceable parts within this supply.
Alesis purchases this supply off-the-shelf from an outside vendor. If there is a problem with the power
supply, It is usually less time consuming to replace the whole power supply.
CAUTION: HIGH VOLTAGE. AVOID TOUCHING THE POWER SUPPLY WHEN THE
UNIT IS ON.
2.2 Front Panel PCBs
The four front panel PCBs are essentially a series of LEDs and switches. The controller for the
Front Panel PCBs is on the Main PCB and all of the LEDs, diodes, and switches are shown on the front
panel PCB schematics. Refer to section 3.4 for details on troubleshooting these PCBs. Refer to
Appendix A for schematic information on these PCBs.
2.3 Main PCB
The Main PCB contains all of the connectors and electronics needed to operate the BRC. At the
heart of the BRC are the three software chips: the Hitachi H8/534 microprocessor (U10), the Field
Programmable Gate Array (U11), and the EPROM (U9). Refer to Appendix A more information on the
wiring of these chips.
The Hitachi H8/534 microprocessor controls all the functions of the BRC including
communication to and from the ADATs, LED multiplexing, switch scanning, and user software
interface. It stores, receives, and generates the functions for BRC operation and uses the FPGA to
execute all required logic. Additionally, the Field Programmable Gate Array (FPGA) replaces several
logic chips with one customized logic chip. It is programmed once to control the logic within the BRC.
Finally the EPROM provides the software for the operation of the BRC.
The basis for the BRC's synchronization is its 4.8 MHz VCO which goes straight into the FPGA.
Most frequencies generated by the BRC are achieved by frequency division of the VCO by the FPGA
with the functions defined by the microprocessor.
2.3.1 VCO Circuit
The VCO, which can be founding by probing the FPGA at pin 43, is a 4.8 MHz square wave
generator from which other frequencies are produced within the BRC by division within the FPGA. A
250 Hz pulse, routed through the control logic, biases the gate of an FET that prescribes a control
voltage which sets the VCO's frequency. This creates a 4.8 MHz sinusoid at the anode of the varicap,
D12, in the tank circuit to drive the HCU04 amplifiers.
3