ENSONIQ EPS-16 PLUS User manual

Keyboard and Rack
PIN 93120013 01-A Isnscnial@
THE TEcHNOLOGY THAT PERFoRMS

ENSONIQ Customer Service
Hours:
Monday through Friday
9:30 AM to 6:30 PM Eastern Time
Closed for lunch 12:15 PM to 1:15PM
EPS-J6 PLUSService Manual
NOTES:
Parts ordering in U.S. and Canada:
1-800-441-1003

Table of Contents
TABLE OF CONTENTS
Page
Important Things to Know About the EPS-16 PLUS:
1. Getting Around the EPS-16 PLUS . . . . . . . . . . . . . . 1
2. Keyboard and RackSimilarities .. . . . . . . . . . . . . . . 1
3. The EPS-16 PLUS Keyboard Assembly and the Rack KPC Simulator 1
4. TheDisk Drive . . . . . . . . . . . . 2
5. Operating System (O.S.) . . . . . . . . 3
6. Plastic Case (EPS-16 PLUS Keyboard only) 3
7. EPS-16 PLUS Rack Screws .. . 4
8. High Retention Force Connectors 4
Figure 1 - Scribe. . . . . 4
Communications Path . . . . . . 5
Figure 2 - Communications Path 5
Power Supply
Checking the Power Supply. ... . . . . . 7
Figure 3 - AC Line Voltage CheckPoints . 7
AC Line Voltage Measurements . . . . . . 7
Power SupplyMeasurements . . ... . . . . 8
Figure 4 - Power Supply Voltage CheckPoints 8
Transformerand Power Supply Voltage CheckPoints 8
Testing the Power Supply Unloaded .. . . . . . . . . 9
Figure 5 - Incorrect Power SupplyVoltages (flow chart) . 9
Display
Display Self-test Mode. . .
Self-Test Chart. . . .' . .
Troubleshooting Guide. . . . . . . . .
Figure 6 - Footswitch problem (flow chart)
Figure 7 - No LEDs Lit (flow chart) . . .
Figure 8 - Some LEOs Lit (flow chart) . . .
Figure 9 -
All LEDs Lit, No Display (flow chart)
Most Commonly Asked User Questions
EPS-16 PLUS Test Procedure:
1. Power Up ........ .
2. Load in Sounds ............ .
3. Keyboard Test (EPS-16 PLUS Keyboard Only) .
4. Disk Check . . . . . • • . . . . . . . .
5. Sound Check . . . . . . . . . . . . .
6. Mono Output and Headphone Test . . . . .
7. MIDI Test (EPS-16 PLUS Keyboard Only)
8. Footswitch Test . . . . . .
9. Analog Test Page . . . . . .
10. Sampling Test . . . . . . .
11. Output Expander (OEX-6) Test
12. ESP Effects Test 1 .....
13. ESP Effects Test 2 . . . .
EPS-16 PLUS Burn-in Test Program
EPS-J6 PLUSService Manual
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Table of Contents-1

Tableo! Contents
EPS-16 PLUS Hardware Notes:
EPS-16 PLUS Keyboard and Rack . . . . . . . . .
Figure 10 -Trace cut for Rev A, B, or C Main Boards
Keyboard Only . . . . . . . . . . . .
Rack Only .............. .
Figure 11 -Hardware Notes for the Rack .
Error Messages . . . . . . .
.'. . . . . .
Software Notes:
Checking the Software Version
Bootup ROM Changes . . . .
O.S. Disk Version 1.10 Changes
EPS-16 PLUS Keyboard Only Section ...
Figure 12 -EPS-16 PLUS Keyboard. ExplodedView
Section A - Replacing the EPS-16 PLUS Main Board . . . .
Section B - Replacing the EPS-16 PLUS Keypad/Display Board.
Figure 13 -
EPS-16 PLUS Button Colors . . . . . . . . .
Section C - Replacing the EPS-16 PLUS Keyboard . . . . .
Figure 14 -Bottom of Case ............. .
SectionD - Replacing the EPS-16 PLUS Power SupplyBoard.
Section E - Replacing the EPS-16 PLUS Transformer . . . . . .
SectionF - Replacing the EPS-16 PLUS PitchIModWheel Assembly
SectionG - Replacing the EPS-16 PLUS LineFilter .
Section H - Replacing the EPS-16 PLUS Disk Drive.
EPS-16 PLUS Rack Only Section ...... .
Figure 16 - EPS-16 PLUS RackExplodedView ..
Section A - Replacing the Rack MainBoard . . . .
Section B Replacing the Rack Keypad/Display Board.
Section C - Replacing the Rack KPC Simulator Board.
SectionD - Replacing the Rack PowerSupplyBoard
Section E - Replacing the RackTransformer . . . .
SectionF - Replacing the Rack OEX-6 Board . . .
Section G - Replacing the Rack Line Filter. . . . .
SectionH - Replacing the RackDisk Drive. . ... . .
Section J - Replacing the Rack MemoryExpanderBoard . .
Drawings
Figure 1 - Scribe . . . • . . . . . . . .
Figure 2 - Communications Path . . . . . . . . . . .
Figure 3- AC Line Voltage Check Points. . .
Figure 4 -
Power Supply Voltage CheckPoints . . . .
Figure 5 - Incorrect
Power Supply Voltages (flow chart) .
Figure 6 - Footswitch problem (flow chart) . . . .
Figure 7 -
No LEOs Lit (flowchart) . . . . . . .
Figure 8 - Some LEDs Lit (flow chart) . . . . . .
Figure 9 - All LEDsLit, No Display (flow chart) . .
Figure 10 - Trace cut for Rev A, B, or C Main Boards
Figure 11 -Hardware Notes for the Rack only.. . . . . . . . .
Figure 12- EPS-16 PLUS Keyboard Exploded View
Figure 13 - EPS-16 PLUS Button Colors . . . . . . . .
Figure 14 -Bottom of Case ........... ... .
Hgure 16 - EPS-16 PLUS RackExplodedView ..
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Table of Contents-2 EPS-16 PLUS Service Manual

Important
IMPORTANT THINGS TO KNOW ABOUT THE EPS-16 PLUS
IF YOU OONT READ ANY OTIIER PART OFTIllS MANUAL, READ TIllS SECTION.
As with every ENSONIQ product, all EPS-16 PLUS service will be handled through the ENSONIQ
Module Exchange Program. Rather than diagnose and exchange individual components, you will
replace complete
mcxlules. We feel that this is the most time and cost effective method of repair,
both for you
and your customers.
The instructions in this manual are for both the EPS-16 PLUS Keyboard and Rack
unless otherwise noted. Where
the instructions say to check the keyboard of the EPS-16
PLUS, substitute acheck of the KPC simulator board on the EPS-16 PLUS Rack.
When troubleshooting
an EPS-16 PLUS, remove any optional modules that might be present. This
will prevent a faulty option from complicating your troubleshooting.
I. GETTING AROUND THE EPS-16 PLUS
You will need:
a. EPS-16 PLUS Operating System (O.S.) Disk
b. EPS-16 PLUS Test Disk (including test sounds)
c. Communications Test Board
d. EPS-16 PLUS Musician's Manual
2. KEYBOARD AND RACK SIMILARITIES
The Main Board and PowerSupply board are the same for both the EPS-16 PLUS Keyboard and
Rack. However, there are physical differences that willrequire
you to specify which unit you are
orderingparts
for. The disk drive is the same for both units. The KeypadlDisplay boards are
different . ..
Insteadof:a Poly-Key Keyboard assembly (with KPC board), the Rack has a KPC simulator board.
The KPC simulator
board. passes information between the KeypadIDisplay board and the Main
Board (like the KPC boarddoes for the Keyboard unit). In the rest of this manual, wheneveryou
see "Keyboard assembly," substitute
KPC simulatorfor the Rack (except where otherwise noted).
The operating system is only
on the EPS-16PLUS O.S. disk. This disk is the same for both the
EPS-16 PLUS Keyboard and Rack. .
The EPS-16
PLUS Rack has the OEX-6 Output Expander and :ME-16 PLUS memory expander
built-in. These two expanders
are options for the Keyboard unit. FLASHBANK (FB-l andFB-2
Kits) and SCSI (SP-2 Kit) are options for both.
3. THE IEPS-16 PLUS KEYBOARD ASSEMBLY
and the KPC SIMULATOR BOARD
The Poly-KeyTM Pressure Keyboard assembly on the EPS-16 PLUS (and the KPC siinulatorboard
on the RaCk) is a complex module that contains its own computer and software. So, when
necessary, you will be swapping itout as a whole unit Display information sent to and from the
Main Board is processed throQgh the Keyboard assemblylKPC simulator. What might appearto be
afrozen display, therefore, could be abadKeyboard assemblylKPC simulator. For more
troubleshooting hints, see Communications Path on pp. 5-6 and flow charts on pp. 9, and 12-15.
EPS-J6 PLUS Service Manual
pagel

Important
IMPORT ANT! Keyboard assembly EPROM Version (EPS-16 PLUS Keyboard only)
Each version
of the Keyboard assembly EPROM is optimizedfor the hardware that is within the
keyboard assembly. Formore information about the Poly-Key Keyboard assembly, see ENSONIQ
Service Bulletins
#9B and II.
The 2O-pin Ribbon Cable <Keyboard aSsembly/KPC Simulator)
When reconnecting this cable to the Main Board, make sure that the striped side is alignedwith pin 1
and that the cable
is not mis-pinned. If the cable ~ mis-pinned or installed backward, fuses F3 and
F4 on the powersupply board will blow. NOTE: If one fuse blows, the otherwill also blow; you
must replace both.
When installing
the keyboard assembly back into the EPS-16 PLUS, be sure that the keyboard
assembly cable
is flat under the keyboard assembly andthatthe ferrite bead is not trapped on top of
the main board .
4. THE DISK DRIVE
Transportinl: a unit
There is a printedlabel near the DiskDrive
on every new unit shipped. This label contains important
information concerning the care
of the EPS-16 PLUS DiskDrive and lists recommendations
regarding the treatment
of the drive during transport. We do not, under any circumstances,
recommend the insertion of an actual disk during transport. Transport the unit only with
nothing
in the drive at all.
PLEASE DO NOT SHIP AN EPS-16 PLUS OR A REPLACEMENT DISK DRIVE
IN A BOX PACKED WITH PEANUTS. If you must, wrap the entire unit in plastic first.
These peanuts may cause severe damage
to theDiskDrive or Keyboardassembly.
What disks to use
Itis veryimportantto use double-sided, double-density 3.5" micro-floppy disks.
The EPS-16
PLUS writes information to every track on a disk, so it is imperative that the disk be of superior
quality
and certified for double-sideduse.
Testini the DiskDrive
The bestway to test the DiskDrive is
by formatting a disk. When a disk is formatted, the EPS-16
PLUS reads and writes every track on thatdisk. If the formatting attemptfails, it is likelythat the
diskitselfis faulty. Always try formatting anotherblank disk before determining that theDiskDrive
is faulty. Unlike some computer systems,
the EPS-16 PLUS does not automatically discard bad
sectors when formatting. The entire diskmust
be goodfor successful formatting.
.
See Hardware Notes.-Rack Only for notes aboutthePanasonic DiskDrive.
page 2
EPS-J6 PLUS Service Manual

Important
5. OPERATING SYSTEM (O.S.)
An EPS-16 PLUS O.S. takes up approximately 170 blocks on a disk so without the O.S. on a disk
you have more room for sounds. The O.S. version on the disk can be easily updated (call
ENSONIQ Customer Service for the latest O.S. version). You cannot copy the O.S. to a disk onto
which you have already saved instruments or sequences, but not the O.S. Attempts to
do so will
result
in an error message.
To update O.S. Version on a floppy disk:
-Insert the disk containing the O.S. you want tocopy (the source disk) into the floppy drive.
-Press Command, then System-MIDI, then 1 (Envl). The display shows COPY OS TO
DISK.
-Press Enter-Yes. The display says MUST ERASE MEMORY, OK?
If you need to save any
sounds or sequences, press Cancel-No and save the data before proceeding.
-Press Enter-Yes. The display says READING OS INTO MEMORY, and then INSERT
FORMATTED DISK.
-Insert the disk onto which you want to copy the
O.S. (the destination disk) into the floppy drive.
- .Press Enter-Yes. The display shows WRITING OS TO DISK while the O.S. is being copied
to the disk.
\Vhen it's done, the display reads COPY OS DONE. ANOlHER? If you want to copy the same
O.S. to another floppy disk, insert another formatted disk and press Enter-Yes. You can repeat
this procedure
as many times as you like.
- When you are done, press Cancel-No.
6. PLASTIC CASE (EPS-16 PLUS Keyboard only)
Avoid Strippin~ Screws
Because the structural components (Base, Control panel, and Wheel cover) are made of plastic,
great care should beexercisedwhen assembling ordisassembling any part ofthe EPS-16 PLUS.
Avoid over-tightening screws in the plastic case when executing any repair
procedure!
\Vhen replacing any of the self-tapping screws, it is possible to over-tighten the screws and strip a
holein the case, making
it necessary toreplace the case or control panel. To keep this from
happening, follow these procedures:
a. Beforereplacing a self-tapping screw
(or screws) into a stripped hole, put adrop or two of
LOCKTITE, Super Glue Gel, or RTV into the hole.
b. Install the screw, and tighten itonly until the sub-assembly being attached is snug against the
case. Do not tighten the screw any further. When the glue sets, the screws will hold the
sub-assembly tightly in place.
Itis important
to make sure that there are no loose screws inside the unit, as they may come loose
and short out something.
Brass Inserts
To prevent stripping, there are brass inserts in the Main Board ground boss (mounting standoff) and
in the four control panel holes. Be sure to use machine screws in these locations. Do not use a
self-tapping screw in a brass insert as this will ruin the insert.
EPS-16 PLUSService Manual page3

Important
7 . EPS-16 PLUS RACK SCREWS
Because the Control Panel is an aluminumextrusion, great care should be taken when assembling or
disassembling any part of it To avoid stripping and to aid in alignment, you should use no more
than 8 inchllbs
of torque and try to install the screws into the existing holes in the panel.
8. HIGH-RETENTION FORCE CONNECTORS (Repair Technicians Label)
In all EPS-16 PLUS Racks and in later Keyboards, there is warning{mformation label just for you.
We just wanted tolet you know that we have switched to a higherretention force connector on our
transformers. This means it will be very difficult to remove this connector by just pulling. We
recommend the use of a scribe, screwdriver or similarobject to remove this connector. Due to the
benefits
of a high-retention force connector, we will be adding them inotherplaces on the EPS-16
PLUS harness. Watch out for thein, andplease don't pull on the wires!
We have found that some units have developed further problems once a module has been changed.
This
may be a result of improperhandling of cables. We suggestremoving allcable connectors
using the angledend
of a scribe (see below).
- - ,
Figure 1- Scribe
These can be found in the following catalogs:
• Techno-Toolcatalog 38, page 204, part number
400PRI44
• Newark catalog lID, page 1024, partnumber76-1510
page 4
,
EPS-J6 PLUSService Manual

Communications Path
COMMUNICATIONS PATH
It is imponant that you completely understand the communications path of the EPS-J6 PLUS.
Please readthis carefully.
The EPS-16 PLUS Main Board, KeypadlDisplay Board and Keyboard assembly are complete
computer systems in themselves, each with its own microprocessor and operating software. The
modules communicate with each other using serial communication ports. Whenever a
key is played
on the Keyboard, for example, the Keyboard assembly microprocessortransmits this infonnation to
the microprocessoron the Main Board.
The KeypadlDisplay Boardcommunicates with the Main Boardthrough the Keyboard assembly.
Whenever the Main Board wants to put a message on the Display, it sends the message to the
Keyboard assembly which then passes it on to the Display. Whenevera button is pressed on the
controlpanel, the KeypadlDisplay Board sends the message to the Keyboard assembly which, in
turn, passes it on to the Main Board.
The communications path is shown inFigure 2. The Main Board communicates with the Keyboard
assembly over a two-line asynchronous interface carried
by the 20-pin Keyboard assembly ribbon
cable. 'The Keyboard assembly communicates with the Keypad/Display Board overa three-line
synchronous interface which is carried overto the MainBoard via the 20-pin ribbon
cable, then up to
the Keypad/Display Board viathe 7-pin Display cable on the EPS-16 PLUS and the 10-pinDispiay
cable on the EPS-16 PLUS Rack.
Due to thecomplexity of the modules involved, it is often difficult to detemrlne which moduleis at
fault when a communications problemoccurs. To facilitate troubleshooting, a Communication Test
Board, TestDisk and Bum-in Test Disk are available.
KEYPAD/DISPLAY BOARD
DATA DATA
CLOCK
IN our our
J
7-PIN DISPLAY
CABLE
MAINBOARD
DATA
DATA
,0
()
0115
IN our C 4)
(~ 112
2O-PIN RIBBON
,,
CABLE
, , \
KEYBOARD!
DATA DATA DATA DATA CLOCK.
, KPC SIMULATOR our IN our
IN IN
ASYNCHRONOUS
SYNCHRONOUS PORT
FORT
~\.. ~
Figure 2 -Communications Path
If a communication problem occurs (i.e., no display orno response to button presses or keys), it
could be something as simple as a ibad ribbon cable or Display cable, or it couldbe a problem in one
?f the modules. To help you identify a faulty module, a special Communication Test Board is
mcluded available from ENSONIQ Customer Service. The CommunicationTest Board simulates the
operation of the Keyboard assembly andcan be used as a "known good" module in place of the
Keyboard assembly fortroubleshooting.
EPS-J6 PLUS Service Manual page5

Communications Path
IMPORTANT!
When using the Communication Test Board, keep in mindthat it is sensitive to static discharge.
Handle the board by the edges andstore it in the anti-static shipping bag when notin use. Do not let
the board shan out when testing, place an insulator (cardboard, paper, etc.) underneath it.
Attaching the Communications Test Board
If an EPS-16 PLUS has a communications problem, turn the unit off and unplug the 20-pin
Keyboard assembly ribbon cable from the MainBoard at-connector112. Plug the
20-pin ribbon
cable
from the Communication Test Boardinto 112. This will eliminate the Keyboard assembly as a
variable.
Turn the system on. If the communications problempersists, you know the Keyboard
assembly
is not at fault If communicationis restarted, however, the Keyboard assembly is at fault.
See the flow charts on pp. 12-15 for troubleshootingprocedures.
There is
one funher complication. Since the communications path between the Keyboard assembly
and Keypad/Display Boardis routed through the Main Board, there is a remote possibility that the
printed circuitconnections between the two connectors
are defective. If you have an EPS-16 PLUS
that has a problem communicating with its KeypadlDisplay Board, you may want to verify continuity
between
the connectors onthe Main Board Turn off the power and unplug the 2O-pin ribbon cable
from the
EPS-16 PLUS MainBoard at 112 and the EPS-16 PLUS 7-pin Display cable from the
Main
Board atJl5. Using an Ohmmeter, verify continuity between the following points on the Main
Board:
20-pin Keyboard Connector
Pin 1
Pin 3
PinS
page 6
7-pinDisPlay Connector
to Pin 1
to Pin 2
to Pin 3
EPS-J6PLUS Service Manual

EPS-J6PLUS Power Circuitry
CHECKING THE POWER SUPPLY
Many EPS-16 PLUS problems may be related to a faulty PowerSupply, Transformer or Line Filter.
You shouldcheck these before troubleshooting the rest of the unit.
Check to make sure that all the cable connections are secure and correct. Plug the EPS-16 PLUS in
and turn it on. Mter the EPS-16 PLUS has warmed up for five minutes, begin to test the voltages at
the points shown in Figures 3 and 4~ If the voltages vary outside the allowable limits, follow the
procedure described under TESTING
TIlE POWER SUPPLY UNLOADED before replacing it
Green
Line
Filter Top
Lug
@ WARNING!
There are dangerous
Voltages present in
this area.
To Power ",nT""'"
NOTE: All wires
come from the bottom
of the transfonner.
Figure3 -
AC Line Voltage Check Points
AC LINE VOLTAGE MEASUREMENTS (see Figure 3)
With the powerswitch OFF, With the power switch ON,
the proper AC Line Voltage
the proper AC Line Voltage shouldread from:
shouldread from: 2B-IA, 2B-IB, 2B-3B, 2B-3A
2B-IA, 2B-2A, 2B-3B There should be no voltage across the
power switch.
EPS-J6 PLUSService Manual
page 7

EPS-J6 PLUS Power Circuitry
POWER SUPPLY MEASUREMENTS
The voltage and part number of the Transfonner is denoted by the label on the top of the
Transformer.
The Power Supply part numberis silk-screened on the left side of the Power Supply
PC board.
I F2 J
1.5 Amp, 25 v
I FI ~
dAmp,25 V
F5
The Transformer part numbers forthe EPS-16 PLUS are:
100V 1450000622 230V 1450000252
120V 1450000242 240V 1450000832
TRANSFORMER AND POWER SUPPLY VOLTAGE CHECK POINTS
The proper AC Line Voltage for each EPS-16 PLUS should be printedon the top of the
Transformer. Figure 3 shows the checkpoints forreading the AC Line Voltage. Figure 4 shows the
connector terminal numbers forthe PowerSupply and Transformer. Itis normal for Line Voltage to
vary +/- 10%.
The following chart lists thevoltage ranges for properoperation of each supply (fully loaded) and the
appropriate terminals
to read across with the volt meter (refer to Figure 4 for terminallocations):
De~i&nali2n
I~rmiDals
CQDD~s:tQ[
AIIQ!fa.bI~ [aD&~
Units
+
Digital Supply 1 3 J4 13.00 to 18.70 VACrms
Analog Supply 4 6 J4 22.00 to 28.60 VACnns
Display
Fllament
7 9 J4
4.70
to 6.05 VACrms
+VA 10
11 J1 +20.00 to +28.00
VDC
-VA 12
11
J1
-20.00 to -28.00
VDC
+5 Analog 14
13
J1
+4.75 to +5.25
VDC
+VDigital
15 13
11 +7.20 to
+12.10
VDC
+5 Memory 16
13 11
+4.75 to +5.25
VDC
+5Digital
18 17 11
+4.75 to +5.25
VDC
+5X
24 23
13 +4.75 to +5.25
VDC
-35 25 23 J3 -29.00 to -37.20
VDC
FIlament 27 28 J3
4.70
to 6.05 VACnns
DisplayOffset 27 26 J3 -22.70 to -31.50
VDC
+.5X 19 20 J2 +4.75 to +5.25
VDC
page8 EPS-J6PLUSService Manual

EPS-J6 PLUS Power Circuitry
TESTING THE POWER SUPPLY UNLOADED
If the Power Supply readings exceed the indicated tolerance (particularly the +5 Digital line between
tenninals 18 and 17 or +5 Memory line between terminals 16and 13) it is possible that a defective
component
on the Main Board is drawing the Power Supply down. In this case, you should test the
Power SuppIy unloaded before proceeding.
Incorrect power supply voltages
Tum the unit OFF Check the fuses.
Verify the the properLine Voltage is
present Turn the unit ON.
INCORRECT POWER
SUPPLY VOLTAGES
===_---NO-- .... ~~An better nowJ
YES
Tum the unit OFF. Disconnect
the Keyboard cable from the
main board. Turn the unit ON.
...( Replace
the Keyboard/KPC)
NO ---IPl~ Simulator (see Section C). .
YES
Turn the unit OFF. Disconnect the cable
between the powersupply and the
Keypad/Display Board. Tmn the unit ON.
Replace the
==----NO ~ Keypad/DisplayBoard
YES
Tmn the unit
OFF. Disconnect the
cable between the powersupply and
the main board. Tmn the unit ON.
(see Section B).
Replace the Main
==---NO---1~ Board (see Section A).
YES
Replace the Power Supply
Board (seeSection D).
EPS-J6 PLUSService Manual
Figure 5 -
IncorrectPower
SupplyVoltages
page 9

Display Self-TestMode
DISPLAY SELF·TEST MODE
When the KeypadlDisplay is receiving powerfrom the PowerSupply but is not in proper
communication with the Main Board, the K.eypad/Display Board enters Self·test
mode. In Self-
test mode, theDisplay remains blank: until you press the buttons on the control panel. Pressing
various control panel buttons will cause the Display to printcharacters, home the cursor, etc.
Using Self·test Mode to Diagnose the Keypad/Display Assembly
1. If the unit comes in with a blank display, but is in Self·test mode (i.e., the Display
prints
out characters when controlpanel buttons are pressedaccording to the chart below) this
indicates the problemis eitherthe Main Board
or the communication linkbetween the Main
Board, Keyboard assembly and the KeypadlDisplay
Board Beforereplacing anything, check all
connections, particularly the 20-pin cable to the Keyboard assembly.
If pressingbuttons ca~ses only the leftmostcharacter of the display to change, this usually
indicates a defective cable connection (20-pin ribbon cable) between theMainBoardand
Keyboard assembly orpossibly a badKeyboard assembly.
2.
If the unit is in Self·test mode but the display does not respond according to the
chart below, the problem is most likely in the KeypadlDisplay Board If certain buttons do
not function properly during normal EPS-16 PLUS operation, test them while the display is in
Self-testmode.
If you can'tisolate a problemthat seems related to the display, the display can be forced into Self-test
mode using the follOwing procedure. With the poweroff, face the front of the unit, then:
Jumperthe left
(-) side of C19 (located below the MIDI Out jack) topin 13 of U20 (WD 1772). On
power up, the display will stay in Self-test as long as the jumper is connected, allowing you to check
the Keypad/Display Boardindependently.
The Chartbelow details how the controlpanel buttons are mapped in Self-testmode:
Eri:ss:
DiSula!
Bi:ads:
Pri:SS: DiSula!
Ri:ads:
LOAD 8 Down Arrow
4.
COMMAND $ LeftArrow .
EDIT
1. RightArrow /
INS1RUMENT
CANCEL-NO ?
SEQ-SONG 3 EIDER-YES (Home Cursor)
SYSTEM:-M1DI 9 Instrument-Track 1 Space
EFFECTS
Instrument-Track2 &
l/ENV 1 + Instrument-Track 3 ,
2/Er:..c"'V2
0 Instrument-Track4 2
3/ENV3
1 Instrum.ent-Track 5 "
4/PITCH
6 Instrument-Track6 (Home Cursor)
5lFILTER 7 Instrument-Track7
5.
61AMP
< Instrument-Track 8 4
71LFO =
EFFEcr SELEcr-BYPASS 2.
8/WAVE (Home Cursor) SAMPLE >
9/LAYER (Home Cursor)
RECORD
o.
O/I'RACK * STOP/CONTINUE 5
UpArrow
3.
PLAY
6.
pageJO
EPS-J6 PLUSService Manual

Troubleshooting Guide
TROUBLESHOOTING GUIDE
Often the faulty module in an EPS-16 PLUS can be determined through normal use. Sometimes, it
is difficult toisolate the problem. The following flowcharts can help you diagnose units that appear
dead (no display).
When troubleshooting an EPS-16 PLUS, always disconnect any expansion devices that may be
present (such as the memory expander, SCSIInterface or OEX~ OutputExpander). This will
prevent a faulty expanderfrom complicating yourtroubleshooting. Theprocedures for testing the
Memory Expander and the SCSIInterface are included with the corresponding expander. The
procedure for testing the OEX-6 can be found on p. 19.
The following pages include troubleshooting flow charts:
~Problem
9 IncorrectPowerSupply Voltages
12 Footswitch problems
13 EPS-16 PLUS with No LEDs Lit
14
EPS-16 PLUS with Some LEDs Lit
15 EPS-16 PLUS with All LEDs Lit, No Display
Troubleshooting an EPS-16 PLUS with a Footswitch Problem (see Figure 6)
If one or both ofthe footswitches do not operate properly, make sure that the footswitches are set to
the proper mode (on the Edit/System·MIDI page). See Section 2 of the EPS-16 PLUS Musician's
Manual) formore information. .
The SUSTAIN Fr SWITCHparameter corresponds to the right pedal of SW-5 or single pedal
SW-l. The AUX FT SWITCH parametercorresponds to the leftpedal of SW-5 only. The SW-5
is the Dual Footswitch (piano-type) available fromENSONIQ. .
On the Edit/S MIDIsystem· .page:
SUSTAIN FT SWITCH AUX FT SWITCH
Footswitch
SW -1 single footswitch, or
SW -5 left pedal
. SW-5 rightpedal
Default SUSTAIN OFF
Option rightPATCH SLbutton sequencerSTART/STOP
Option -leftPATCH SELbutton
If the footswitch modeis correct and thefootswitch still doesn't function properly, there is either a
problem with the Main Board, the KeyboardIKPC or the 2O-pinribbon cable connecting the two.
Although the footswitch
jack is mountedon the Main Board, the footswitch signals are carried over
to. the KeyboardIKPC by the 2()-pinribbon cable, where they are sensedby the KeyboardIKPC
mlcroprocessor.
EPS-16PLUS Service Manual page
11

Troubleshooting Guide
TROUBLESHOOTING AN EPS-16 PLUS
WITH A FOOTSWITCH PROBLEM
~-NO
YES
Set both footswitches to act as Patch Select Buttons.
Press Edit then System-MIDI, scroll to
SUSTAINFI'SWITCH (right orsingle pedal) and
press the
up arrow button to set it to PATCH SL.
Scroll right once to AUX Fr SWITCH (left pedal)
and set it to PATCH SEL.
Select
PIANO 241. Press Edit, then double-click
on Instrument. Pressing either footswitch should
cause the appropriate patch indicator to change in the
·Iefunost two characters
of the display.
~----YES---""
NO
Turn the unit OFF. Attach the communications
testboard. Tum the unit ON and boot it up
nonnally. The display will show'" KBD
FAll...ED-TRY AGAIN? Press Cancel·No.
page12
Load in and then selectPIANO 241.
Set both footswitch to act as Patch
SelectButtons (see above).
~--NO
YES
Replace Keyboard/KPC Simulator'
Board(see Section C).
... If your communications test board has
an edge connector (4090013601) this
message will not appear.
Replace the MainBoard
(see Section A).
Figure 6 -
Footswitch Problem
EPS-16 PLUS Service Manual

NoLEDs lit.
YES
NO
i Test the powersupply
: unloaded. Go to Incmrect
PowerSupply Voltages .
flow chan, p. 9.
E~S-16 PLUS S~ice Manual
YES
NO
Troubleshooting Guide
TROUBLESHOOTING AN
EPS-16 PLUS WITH NO LEDS LIT
NO
Replace the
YES
Check
KeyboardIKPC
20-pin ribbon
cable for
improper
connnection
..
YES· KeypadlDisplay
Board (Section B).
Figure 7 -
NoLEDsLit
page 13

Troubleshooting Guide
TROUBLESHOOTING AN EPS-16 PLUS
WITH SOME LEDS LIT
>--NO
Test the power supply
unloaded.
Go to Incorrect
Power Supply Voltages
flow chart on p. 9.
YES
>- __ NO_ ........ Repaircable
JIll"" andretest.
YES
Place scope ground onthe left
lead (negative) of C19 and probe
on pin 4 of J15-DISPLAY.
page 14
YES
Replace the
KeypadlDisplay board
(see Section B).
>--NO
Replace the MainBoard
(see Section A).
Figure 8 -
SomeLEDs Lit
EPS-16 PLUS Service ManZllll

ALL LEDS LIT,
NO DISPLAY
Troubleshooting Guide
TROUBLESHOOTING AN EPS-16 PLUS
WITH ALL LEDS LIT, NO DISPLAY
Test the power supply
NO ... unloaded. Go to Incorrect
:>--- --Ir.c Power Supply Voltages
YES
Force the unit into self-test mode:
Jumperthe negative (left) side of
C19 to pin 13 ofU20.
flow chan, p. 9.
... Replace the
~-- NO --Ir- KeypadlDisplay Board
(see Section B).
YES
>- __ NO ___ Replace the Main
YES
YES
Replace the Keyboard/KPC
Simulatorboard (see Section C).
EPS-16 PLUS Service Manual
Board (see Section A).
">---NO .c Repair andretest. )
Figure 9 -
All LEDs Lit, No Display
page 15

User Questions
MOST COMMONLY ASKED USER QUESTIONS
The following questions are the most commonly asked by end users. Our CustomerService
Representatives (CSRs) resolve these situations over the telephone daily.
Question:
CSR:
Question:
CSR:
Question:
CSR:
Question:
CSR:
pageJ6
How doI Mix a Track or a Song?
Sequences (Tracks)
1) SetRECORD MODE to ADD (see Section 8 o/theMusician's Manual)
2) Select the Instrument-Track
3) Press Edit then Track, scroll left to MIX
4) Set mixto the desired value
5) Hold Record and press Play
6) Letthe Sequencer play one bar
7) Press Stop
8) Answer YES to KEEP=OLD - NEW
In Song Mode
1) Chain sequences into a Song
2) SetRECORD MODE to ADD
3) Select the Instrument-Track
4) Press Edit then Track, scroll left
to MIX
5) Hold Record and press Play
6) Mix Track through entire Song using the Data Entry Slider or the CV Pedal
withPED=VOL
7) Answer YES to KEEP=OLD - NEW
The EPS-16 PLUS will not record a sequence from external sequencer in MUL 11
mode.
You must have O.S. version 1.1
or higher.
Why won'tthe
EPS-16 PLUS let me edit convertedMirage sounds?
WS=1 contains the actual wavesample informationfor the Lower sound, WS=17
for the Upper. All otherwavesamples (30 of them) are copies of WS=1 or
WS=17. Therefore. isolatethe desired wavesample(s) as follows:
1) Create a new Instrument (see Section 3 o/the MusiCian's Manu.al)
2) Create a new Layer in that Instrument(see Section 7 o/the Musician's
Manuol)
3) Copy desiredwavesample into the new Layer (see Section 6o/the
Musician's Manual) .
4) Truncate the new wavesample (see Section 6 o/the Musician's Manual)
5) Edit as you wish
Why do someothermanufacturer's instruments crash when playedfrom an
EPS-16 PLUS keyboard?
Theseinstruments cannothandle the vast amount
of MIDI data thatPoly-Key
generates. Turnthe key pressure settings to CHANor OFF on MIDI and each
INSTRUMENT, as follows:
1) Press Edit, then
System-MIDI (see Section 2 o/the Musician's Manual)
2) Scroll to BASECHANNELPRESSURE=KEY
3) Change it to CHANNEL or OFF
4) Press Edit, then Instrument (see Section 3 o/the Musician's Manual)
5) Scroll toPRESSURE MODE=KEY
6) Change it to CHANNEL or OFF
EPS-J6PLUSService Manual