Kurzweil PC88 User manual

PC88
Service Manual
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EURZWHIL Secs cee = SSeS Tec Petormence Coneroter Pome eae
naan] sete
| / / — €) se
A) Fa) de: = too oe
B a —
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ae Colo
MULT AAA
©1995
All
rights
reserved.
Kurzweil
is
a
product
line
of
bead
Chang
Co.;
Kurzweil,
PC88,
and
VGM
are
trademarks
of
Young
Chang
Co.
All
other
products
and
brand
names
are
trademarks
or
registe:
trademarks
of
their
respective
companies.
Product
features
and
specifications
are
subject
to
change
without
notice.
Part Number: 910276 Rev. A

INSTRUCTIONS PERTAINING TO A RISK OF FIRE,
ELECTRIC SHOCK, OR INJURY TO PERSONS
IMPORTANT SAFETY AND
INSTALLATION INSTRUCTIONS
WARNING - When using electronic products, basic precautions should always
_ be followed. Read all of the Safety and Installation Instructions before using
the product.
Do not use this product near water, such as near a bathtub, sink, in a wet
basement, near a swimming pool, or the like.
This product, in combination with an amplifier and speakers or headphones,
may be capable of producing sound levels that could cause permanent hearing
loss. Do not operate for a long period of time at a high volume level of at a
level that is uncomfortable. If you experience any hearing loss or ringing in the
ears, you should consult an audiologist.
The product should be located away from heat sources such as radiators, heat
registers, or other products that produce heat.
The product should be connected to a power supply only of the type described in
the operating instructions or as marked on the product.
This product is equipped with a polarized line plug (one blade wider than the
other). This is a safety feature. If you are unable to insert the plug into the
outlet, contact an electrician to replace your obsolete outlet. Do not defeat the
safety purpose of the plug.
The product should be serviced by qualified service personnel when:
A. The plug has been damaged; or
B. Objects have fallen upon, or liquid has been spilled into the product; or
C. The product has been exposed to rain; or
D. The product does not appear to be operating normally or exhibits a
marked change in performance; or
E. The product has been dropped, or the enciosure damaged.
Do not attempt to service the product. All servicing should be referred to
qualified service personnel.
WARNING - Do not place the power cord, or the product in a position where
anyone could trip over, walk on, or roll equipment over them. Do not allow the
product to rest on or be installed over cords of any type. Do not place the power
module where it cannot receive cooling air, such as under a rug. Improper
installations of this type may create the possibility of a fire hazard and/or
personal injury.
PC88 Service Manual
ii

RADIO AND TELEVISION INTERFERENCE
WARNING - Changes or modifications to this instrument not expressly
approved by Young Chang could void your authority to operate the instrument.
IMPORTANT - When connecting this product to accessories and/or other
equipment use only high quality shielded cables.
NOTE: This instrument has been tested and found to comply with the limits for
a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference in a
residential installation. This instrument generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular
installation. If this instrument does cause harmful interference to radio or
television reception, which can be determined by turning the instrument off and
on, the user is encouraged to try to correct the interference by one or more of the
following measures:
¢ Reorient or relocate the receiving antenna.
¢ Increase the separation between the instrument and the receiver.
¢ Connect the instrument into an outlet on a circuit other than the one to
which the receiver is connected.
¢ If necessary consult your dealer or an experienced radio/television
technician for additional suggestions.
NOTICE
This apparatus does not exceed the Class B limits for radio noise emissions from
digital apparatus set out in the Radio Interference Regulations of the Canadian
Department of Communications.
AVIS
Le present appareil numerique n’emet pas de bruits radioelectriques depassant
les limites applicables aux appareils numeriques de la class B precrites dans le
Reglement sur le brouillage radioelectrique edicte par le ministere des
Communications du Canada.
PC88 Service Manual
iii

Table of Contents
Chapter 1, Basic Operation
BROAT
PAM
costa
tid
ccedisines
ee
tel
Decal
tat
atau
tlie
ot
So
de
1-1
TOWER
cosciactes
tere
Saati
aera
tos
ecu
eais
eednceesan
eee
ot
eee
1-1
1%,
BG)
eeqvoneeer
ea
ee
erenent
ne
sre
tis
Cnr
ts
et
Omer
ee
rene
Nt
Re
Pee
TEE
1-1
LCD
Contrast
Adjustment
00.00...
cesseeeeeseseeseseseeteseseeneses
1-2
SWAUCH
POCA)
S
Sasesa
te
syu
caticial
eu
neetely
ect
ean
Neoe
glieeemyieese!
1-2
Continuous
Control
Pedals
oo...
cesccsssceccesscesssssscessceeees
1-2
PRUIGIO
QING
seein
its
onem
dl
pete
i
tee
lai
aah
Scena
tetaad
ote
Oran
1-3
Pron
Panel
6a.
ssscehentssiiadcsces
siete
Mass
can,
Sead
caudoes
gaseutit
eis
aa
asnnas
1-3
LCD
and
Cursor
Buttons
.........cccccccssssscecescesceccecescesscesssscaes
1-3
Sound
/Setup
Select
.......cssosesesercccssserssssassssserssecsesssseassseevees
1-4
Internal-VoOiceScs
si:
noe
will
teneie
ici
dads
nea
das
achimte
heed
1-4
MUEDE S@UUDS -siesspcasissintstuseeiestsies AR bre hers heer lead etal a dnt 1-4
ZONE
PAarAaMeters
ced.
siocdisietenipigidaeha
ddaueaestaceedeiarsemans
banal’
1-5
Zone
Select
and
Assignable
Controllers
.......cccccsccssesesseeeeees
1-5
Dieta
Gey
oz
22.5
san
sstatanured
dunce.
Satara
spelen
aiadedasadaiuata
catuieeessianiaee
1-6
Master
V
Oli
ceca
fienidie:
sissies
cnietees
eaeecloiahebtelawuvaxaaceeeeasipetessavinetigens
1-7
PATMC
Bu
lOi
iis
ee
Siacciechevstaitoeivtitd,
oo
ataicenaiete
sexo
Nebelatoss
1-7
|
5
(fol:
gee
en
ete
emt
ae
ne
ee
ere
eee
te
Conte
aR
ee
eT
1-8
Chapter 2, Diagnostics
Did
sriostic
Tests
slau
scstlivlns,
tinsel
ioe
ean
sheutina
cede
eee
Sa
atibiaemouees
2-1
DCANNED
LOSES
sii)
thshgie
iene
viwleaiuamse
Seine
sialtvacieaneniak
ume
beediws
2-1
Entering.
Dia
SnOSti
Cs:
5
20s
cacescecuton
ous
ctactayeuaseelanneanaid
2-2
LCD
and
Control
Panel
Buttons
...........cccccessesssssscsescsssssessesens
2-3
Diagnostic:
Tests:
sissies
aig
scsavibsthorteseret
peared
tieatstia
lesser
ccenisiSini:
2-4
WIC
MIO
DG
a2,
sso
oho
tied
aienurenatunt
ni
aacltont
cancel
nadie
2-4
Burnett
MOG
seiavecacs’
cloncetyettec
iterate
hte
ciaceesssernaedontnerder
2-4
DODO
MOG
es
ales
wi
itictetscaletsh
cidade
ues
balms
ieee
2-5
DOU
MOE
ents
cpiscscindetats
Sie
teccerthentarerdilesd
aclu
betas
satel
Aunaeiee
S
2-6
Description
of
Tests7
fei
ncs
tu
astincwrciniealiesienaea
ne
larcihains
2-7
CPU
Test
aictccrcars-
usage
a
ssn
gh
aiuan
cade
sansudadiessavaniten
eeveiareatan
2-7
Program.
ROM,
Test
siscstensiscsscennntu
ea
dsaecet
thes
tac
smauioctactaines
2-7
TT
CS
Uo
tas
pli
oeser
hates
oie
cts
lowe
tata
aces
Tea
te
2-7
IN
VIR
AINE
TeS0
caitatsicccuecttensts
tediens
casts
tatacttod
cated
sdailbdesct
calcd
2-8
MIDIUART.
Test
csccvesocecueae.
oi
sata
asancandneeeuadads
thexiagee
2-8
DCAMCr:
LOSE
eat
p
ceded
talaga
ae
nner
tn
eaters
2-9
Parallel
I/O
(PI/O)
Test
........cccccscscssssscssseseessssessseesestseesscsees
2-9
PC88
Service
Manual
1U

TIM Ete POSE aks fveere te dtvies coves eno eet ihe deren 2-9
PIOTIOE VASE sxecstcciice eho eet eae at ey ucaieraler belt tatuedinetesete 2-10
Sound ROM: Vest vies cece ssh ea lege Seanad cee tae badd 2-10
Mate Test ciipicscclsececna bids: caselatenenenngeriainalstete tan dutistasoaines 2-11
Delany TRAM Test 2cses a tasesstaetetsnnsnjeadnrsen oataatages focdoabeneanansna 2-11
LEDs TeStertac creed tur eevee i Ase ee 2-11
VGM- Port TeStéisacicie tlt ioresh vinta cekeersas an eee 2-12
COU CSE iy ait ctce eens sates toate aaah ses eeecoataen ek eet 2-13
SCANTIOE TCS US vesos cezszcseswiewserraea dna teouieaven tam svereiereenenesae 2-14
Data Wiel citccccce.teecl tiasaecegedet oy fataetoednas accne te ieeeet seats 2-14
Front Pariel Buttons: «. csecicccscgescassvenssascatiaaviccsnceadetsseeeenes 2-15
Front Panel Suid ers ics ices ane een nae 2-15
Keyboard wsciestiaisisssenttatetdisnyeaneteceencatiedonilerarteisperseersaneastiaahs 2-16
Mod Wheels .....c.ccccscsecsceesseseeeeees Pastas eho et ch 2-17
Switch Pedals wicca eee ass ine eeaiosiinen case 2-17
Continuous Control Pedals .............cccccssssscccceeeenseneeeseeee 2-18
Chapter 3, Disassembly/Assembly
TAtPOC CHO: a esesintsnctei anh ancien atin ene en nines 3-1
EMI Shields/Enclosure Support Wall .........:ccsccesesesenees 3-2
PIG UGS oectecssited A veo ted daca cte, ta alo anasepwnants datesatelpsaeesa nates eabtliags 3-2
Assembly Instructions siidisca.sectseccore: ioc tnaiienian asain 3-3
BMY SHEL AS ass ccssen dacs ewsctsavscaacutvatisa gaaleisth daded sales Kec Synedneawadebotlap cateves 3-4
PIGUne D2 ends etcealerh par aidibanlinseatiananieece el aaneeiesest 3-4
Opening the PC8S sicsicsdsetecestaeusatrccnscasesetaracaredasensttonneiwbvnayierts 3-5
FUGUES O23 ates ssascsvscsesaentnsinclecwanaacscennsles ties ee lghate soluatacubecoeaitebersnecs 3-5
Removing the Top Cover Assembly ........cssesecseeeneetees 3-6
Pipire.3 Aoaiiiiae caigiettneieaariasans pis sbbieuastesderandscaalspaasdelnens 3-6
Pig uire: 3.5 & Jedsasssventieduv conti subitiabancsl cuceodsi cies eeteaeact ines nipiete ates 3-7
PiU 3G cash siyasencecstendecesta stead sagaadeseaep nage ott eee qenceana aeeaeneesiese 3-8
Replacing the Top Cover .......scssssssssssesssssnsserssscsesseetsenonesnees 3-9
Removing the I/O Board ......cccecseeseesssserseeseeesenesessenenereens 3-10
Replacing the [/O Board ......ccccsssesseseeeeseeesenesssnseesenenenees 3-11
Removing the Control Panel/Switch Board ...............+4 3-11
Replacing the Control Panel/Switch Board ...........00+ 3-12
Removing the LCD Board ........ccessseeeeseeneeeeeneneereneneenes 3-13
Replacing the LCD Board .........:ssssssssssenenseneneesseeneesenetsans 3-14
Removing the Slider Board .........cccscccseseeteteeeeeeeteenenes 3-15
Replacing the Slider Board .........ccccssseseseeseeeseeeeeeneteneens 3-15
Removing the Engine Board ........ccccceeeseteeeseseeteeneneees 3-16
Replacing the Engine Board ........ccccscsesseeseseeseesseeneneneees 3-16
Removing the VGM Board .......ccssseeeetsseteneeeneeneneneeneees 3-17
PC88 Service Manual
v
—

Replacing the VGM Boat... cesesssesetseererenenseeeneeees 3-17
Enclosure Support Wall wicvsissciicsssccsessssycvosssanuetsveniwas ese duedeossataeies 3-18
Openiti¢ the: PC88 a4 idisitadaniwis ah NAGS wtdetlagols 3-18
BiG 6G: Daz ssc wsiiyesinle Ruin donctined ns ton nadia Niatameera tiene 3-18
PIG Ure: Bi isis cheastatat oantivacicastuanurteter i edetecariencndeaccnaean aes 3-19
Removing the Top Cover Assembly ...........:scseeseeeeeeeees 3-20
FEL UID. 9 ase Mra css saya sedeaiuents sels Sho tn ernaBRa indi seas hecuee aaa 3-20
Bip re Dil Oh secs cctiee secs eats me) ieresieliGaataens hasten Gieatacs tote ba days 3-21
Pip Ure Sal sss tev. wesc socecnustscvans taped sanoidvnetisiyavialancosasotoats chtamibiecedss 3-22
Replacing the Top Covel ecsicissvsimaisenovacsnteRapicensdanialaiuanine 3-23
Removing the I/O Board... ccccscssssssesssssscsessstseeesceseeses 3-24
Replacing the I/O Board oo... ceecceeeeeeeeeeeeesensseecessens 3-25
Removing the Control Panel/Switch Board ................... 3-25
Replacing the Control Panel/Switch Board 0.0... 3-26
Removing the LCD Board ........cccccesssssesesesseesessnersteeeneees 3-27
Replacing the LCD Board uo... ccccessesesseseesssesssesesencerens 3-28
Removing the Slider Board o.......cececsssesessesceseseeeseeseseees 3-28
Replacing the Slider Board ws ssssssssnesseeseeesereeeeenees 3-29
Removing the Engine Board occ esscesesecsesseecseeeeeeaes 3-30
Replacing the Engine Board ou... cesses esesesesseeeeseens 3-30.
Removing the VGM Boat wiwccsescsssssssesesssesessseseasseseeens 3-31
Replacing the VGM Board ou... csecsesssesececestsesseneneseenens 3-31
Removing the Mod Wheel Assembly .........ccccssssessseseseseeees 3-32
Removing the Keyboard 2 sscsisaatenitsh sinsassauitvetcndiontuietel sissies 3-33
FU BUT 1 25 csacsztahciaacisadienl stars ateaagsdurey astentenbia tee satatan tava iads 3-33
RREMOVW 1g a ROY i vind sees vesietaduhageseseteca ahsuieacteznse sanesarsoaluvaustvdeateek 3-35
Pig Uae Dud sashes shnssseadsnetanscesanenedugatavaniparnonnate ee mubeiasnaukabligadiats 3-35
Natural WHC IRC YS vs cniit tui achdioeel ototench personae sitiosdedhet ass 3-36
SH arp y BIACK CYS sess eauiticl siesta tenets i eee cients 3-36
Replacing a Key sccssesenteihs tS ssvsinseh Se sanisvtebesdabia alien neatesceetgeasedyeact 3-37
Removing the Keyboard Contact Boards ..0.....ceeseeseeeeeeees 3-38
Removing the Treble Contact Board. ..........ccccsssseessesesees 3-38
Replacing the Treble Contact Board oc eceeseteeeeereees 3-39
Removing the Bass Contact Board ........eeseeeereteeerenes 3-39
Replacing the Bass Contact Board oo... cssseeseeeeseseeees 3-39
Removing the Keyboard Contract Strips ..0..... cesses 3-40
PIU 301A scstsaaiasesessddens sacstoeecciiets oat bass saitiiaiiun waunpondinens bine 3-40
Replacing the Keyboard Contact Strips .0.....essseeteneeeeee 3-41
Removing a Key Weight <sscsssssisssecveserssceseunentesdsausconssderadeounels 3-41
PPV UAY SS Vo aca s3hd Boba a char dosaanas ted cheahenar se seae aul aclstacaials 3-42
Replacing a Key Weight ss ssceaicinasissciaicauidewiass 3-43
PC88 Service Manual
vi

Chapter 4, Troubleshooting
INtFOCUCHOR ake see iae eed ace erent
CUSIOMET'S SOUPS saci iesguddeativeenrineeniarntrdneilntedeenles tars
DA VINE DCLUPS ated culver neck ties onnue eel ateneoa meaaie ae
Surface-Mount Devices ........ccccccsccesssscesssecessseceesseceesesseeeesseeees
PE88 RESCtS iscsi hd ieetuiis desactnse er cli Sastre dana’
FAVA ROSCOE ay cdvsschicdonctandbeslaczaccdsiua sharpie tie ouadidelersonentans
SOL IRESEE a iiasakeiges sa vsuescee caatateea otha lus aan oon neaestees
POWeE PLODlOMIS: sitecc chine heeds oaado sedis eae assaeses
Front Panel Problem ..........:..ccccccccccccesessscsecsesesserssscceceecsceccssteees
AUIGIO PLODIEINS wc sioelewchee. eeatckeh ethevee cas enssiat ese AL aeeeaaxs
Internal Sound Problems .............cccccccccsssssssscecceaseseecceesessnsessassees
Keyboard Problems ..........:ccccsseceeseeeees Stes iaeiete tae tent 4
BAUteLy savesuviaisostiaissi dear choaddsdeduchssobasisnesiinscantevedeectesitnensiinauasenetoe@es 4
Removing/Replacing the Battery ...........ccccceeeseeeeenees 4
PEWMIIOLS idea sesvesidevibavas st duaesttass urna dadendiders Ginnie mutase ea tiuies 4
INLEFCOMME CE: Dia PANY exesatpsagcseszass st ansosbadedeuneopaatangastapianoe amamneennns 4
Engine Block Diag@raimy, ..2.secsedesn ta sieeeaniois enlace niie anal eadeceeaeies 4
Table, 37451 Microcontroller ............cccccccccsccccescscessssccssseeseerseees 4
TOS POU Ss rare a hee yi stes cecsse deo RGPaae eae ives ates nea aan 4
Chapter 5, Parts Lists
Tf BO ats 4osechasesheresnstsadanecsesunstadvaccay epdecestis aaspactaues eal aeuachadns dawaatsos
Main Control Panel Board ..........ccccsssccsstecsssssccesneceessceseseersesaees
Slider -BOarG -sesiicduateinstoctaweonaead wa eactai aanceiac carat oes
TCD BOAR hes susteastiotiecccessdotease vet etinea sarees ates Rise Sa viosiadenaiad ereeneks
Engine Board: (DIP) sistent cosaasecaltiatesshnandraieandies
Engine Boatd (SMD) ssc.icciscs. dsc vctianencesgi nadia ieee hci yasataes
Wheels ASSEMBLY is cdescsh sans. serasdebsiertteassesiatatocustedoresiadienoiaencasisers
Keyboard Assembly .i.c.dascsssntiinghisaieaieiadsantianieneiieabeicvases
AIG situa cats ad Catnters ree esau e Neuter tos etaaint ar aueevauceuaCurhiian anmenatatiee
CaSE/ ENClOSU FC ei ieii actu cressaiierictad asad totes Mesa Filede tease teth eet
Par W Al aco tess ws ccsetuarecdeseadecedsDeacheasildetestuetreassiis eutiwass vandern iadeusus
Miscellaneous: a2icesii ction iabccstal de sunicestsestiaandsdhibieiitiade erent
PC88 Service Manual
voli

Chapter 6 Schematics
TO
Board
SHOGt
1
iss. tivc
cache
supers
erie:
che
arnc
ees
dial
Sook
viteameet!
6-3
I/O
Board,
Sheet
2
......cccccccsscsscsssscscseccsscsecsesscssesssscssccesesescessusees
6-4
Main
Control
Panel
Board
.0.....ccccccceecessscsecceccessssseesceasseccsssseees
6-5
DOOR
BOA
sii.
Giietced
ax,
crietsn
Latvape
ead
sndototaetincaaeid
seasote
eke
decdoantindss
6-6
Engine
Board,
SHEGt
ai.
tstb
sound
av
uecesd
veer aiva
decile
vsseestiiatblsay
6-7
Engine
Board
Sheet,
2
aiecsscavehciereeteewsarsnnd
lssdcicaationtine
mlaieslane
6-8
Engine:
Board,
SHEGES
sssiscssiteetss
eins
duardessernssanaesmastaiecibasyieetss
6-9
Engine:
Board,
Sheet
4
is
tices
actaciueslosisesauda
asian
tases
6-10
Engine:
Boards
SHOES
cist
casas
oss
Seales
vars
cud
hcng
sdentees
ceatidactseeoadacd
6-11
Engine
Board,
Sheet
6
........scseccscssssssssssscscsssscssssssscsecscescsssseecesers
6-12
VGM
Board,
Sheet
1
.....ccccscccccsceccesceccescsssescescsscsssssscsscssceesseees
6-13
VGM
Board,
Sheet
2
u.....ccccccccscsscsscsscsscsscescescsscessesessesscssssscessees
6-14
VGM
Board,
Sheet
3
o.....ccccecccsscsscsscsscssceccsscescessescsccssessesesssscnenes
6-15
VGM.
Board,
Sheet
4
isiccasica2itocd
apedte
vetted
eine
Nevins
daioneticsce
Sled
6-16
VGM
Board,
SHG6t
5
xsessscsossiicermrceaniuadeesiveddccossom
abcess!
6-17
WReeIS
Boat
esi
jeg
sccdeGucesxtindee
sedakadpapives
naedovcauciieltadtet
wench
ews
ase
6-18
I
PC88
Service
Manual
viti

Young Chang Distributors
Contact the nearest Young Chang office listed below to locate
your local Young Chang/ Kurzweil representative.
Young Chang America, Inc.
13336 Alondra Boulevard
Cerritos, CA 90703-2245
Tel: [phone]
Fax: [phone]
Young Chang Akki Co.
Kang Nam
P.O. Box 998
Seoul, Korea
Tel: [phone]
Fax: [phone]
Young Chang Akki Co., Ltd., Europe
Industriering 45
D-4060 Viersen 11
Germany
Tel: [phone]
Fax: [phone]
Young Chang Canada Corp.
395 Cochrane Drive
Markham, Ontario L3R 9R5
Tel: [phone]
Fax: [phone]
PC88 Service Manual
ix
~~

Specifications
Physical
. Height:
¢ Width:
*Length:
eWeight:
Electrical
Voltage Range:
Frequency Range:
Input Voltage:
Power Consumption:
Environmental
Temperature (Operating):
Temperature (Storage):
Relative Humidity
(Operating and Storage):
Audio
Output Connection:
Impedance:
Output Level:
Dynamic Range:
45/16" (10.95 cm)
14" (35.6 cm)
545/16" (137.95 cm)
55 Ibs. (25 kg)
120 VAC 240 VAC
100-125 Volts RMS 200-250 Volts RMS
48-65 Hz 48-65 Hz
9.5 Volts AC 9.5 Volts AC
2.0 Amps max 2.0 Amps max
40 to 104° (5 to 40°C)
-13 to 185°F (-25 to 85°C)
5 to 95%, non-condensing
2x 1/4" Mono Phone Plug
2K Ohms
3.5 Volts RMS Max, 1 Volt RMS Nominal
>103 dB "A" Weighted
PC88 Service Manual
x

Chapter 1 Basic Operation
The following is a brief description of the Kurzweil
PC88's Front Panel controls and Rear Panel connections.
This has been prepared for the servicer of the instrument
to give a general idea of basic operation. To examine the
full capabilities of the Kurzweil PC88's functions, consult
the PC88 Musician's Guide.
Rear Panel
The Rear Panel contains the connections for power,
MIDI, audio pedals.
Power 9.5V-AC In MIO! Select MIDI in MID! ThrufOut = MIDI Out
Cc An P eo.
L_s] =! a a a “e |
2.0A
Power
The PC88 uses an external 9.5V, 2.0A ~ AC power
supply. Power is turned on by pressing the rocker switch
into the "on" position (white dot in). Prior to connecting
the power supply, be sure the switch is in the "off"
position (white dot out). .
There is a strain relief mounted on the rear panel so
that the wire from the power supply can be wrapped
around it to prevent damage to the AC jack if the the cord
is yanked. Wrap the wire once, not too tightly, around the
strain relief, before inserting the plug into the socket.
MIDI
There are three MIDI jacks on the rear panel, MIDI In,
MIDI Thru/Out and MIDI Out.
PC88 Service Manual
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Chapter
1
Basic
Operation
Use the MIDI In to receive up to 16 separate channels
of MIDI data into the PC88. The PC88's MIDI Out can send
up to four channels simultaneously.
The MIDI Thru/Out has two functions. To the left of
the MIDI In jack there is a MIDI Select switch. The MIDI
Select is a slide switch which allows you to select either
MIDI Thru or Out. In the Thru position, it allows you to
send data being received by the PC88 through to multiple
MIDI instruments. In the Out position, it doubles as a
second MIDI Out jack which allows you to hook up
multiple instruments.
LCD Contrast Adjustment
Located between the MIDI and the Switch Pedal jacks is.
a rotary knob. Turning the knob adjusts the LCD to
accommodate different playing positions.
Switch Pedals
There are two jacks on the rear panel for switch pedals.
The pedals should have two-conductor 1/4" plugs. Either
normally on or normally off switches can be used. They
are typically used for on/off operations such as sustain,
sostenuto, etc.
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Continuous Control Pedals
There are jacks on the rear panel to connect up to four
external control pedals. The pedals should have 10kQ
linear taper potentiometers with 1/4" tip/ring/sleeve
plugs. They can be used for volume, stereo pan, etc.
PC88 Service Manual
1-2

Chapter 1 Basic Operation
Audio Outs
The Left and Right Audio Out jacks are 1/4",
unbalanced for use with a standard instrument amplifier
or mixer. Should you need to connect the PC88 to a hi-fi
system, you will need cables with 1/4" plugs on one end
and RCA (phono) plugs on the other. Use the Left and
Right Audio Out jacks for stereo or just the Left for mono.
The headphone jack carries the same signal as the
main outputs. Plugging it in does not disconnect the
main outputs. Use a standard 1/4" tip/ring/sleeve
configuration.
Front Panel
LCD and Cursor Buttons
The LCD window displays two lines of text and
numbers. Its contrast may be adjusted to accommodate
different playing positions, by turning the small black
rotary knob located on the rear panel between the MIDI
and the Switch Pedal jacks.
Below the LCD are the two cursor buttons, which
enable you to step through the parameters within a
"menu". The cursor buttons also have a "jump" feature.
This is extremely helpful if you need to move through a
very long menu. If you depress both buttons
simultaneously, you can "jump" to a parameter some
distance down the menu.
PC88 Service Manual
1-3

Chapter
1
Basic
Operation
Sound/Setup Select
This section contains two groups of buttons. Four on
the left and sixteen on the right. |
und/ Select
intemal
Vowes
MIDI
-_
=
‘Stage
Piano.
=
Pano
=.
Pano
ElectricGrand
=
Piano
&
Swings
Stings
Harpsichord
Previous
ra)
Next
Gri
a
Acouste
Guitar
Rock
Organ
Jazz
Organ
Acoustic
Bass
=
ElecticBass
=
SynthPad
The group of four on the left are as follows: Internal
Voices,
MIDI
Setups,
Previous
Group
and
Next
Group.
The
group
of
sixteen
on
the
right
allows
you
to
choose
from
the
16
families
of
sounds
in
the
Internal
Voices
mode
or
setups
from
the
MIDI
Setups
mode.
Internal Voices
On
power
up,
the
PC88
is
in
Internal
Voices
mode.
The
Internal
Voices
mode
has
buttons
labelled
1
through
16.
Pressing
a
different
button
selects
a
different
sound.
Each
button
has
four
groups
of
voices,
A
through
D.
The
group
is
selected
by
pressing
the
Previous
Group
or
Next
Group
buttons.
The
LCD
displays
the
name
of
the
sound,
number
and
group
preset
number.
MIDI Setups
The PC88 is shipped with 32 pre-programmed MIDI
Setups.
If
you
have
a
PC88MX
or
a
PC88
with
the
VGM
option installed, there are 64 pre-programmed MIDI
Setups. The PC88 can have up to 128 pre-programmed
MIDI
Setups
altogether.
Factory
setups
are
stored
in
ROM
and cannot be erased. Modifications are stored in RAM
until
deleted.
If
the
modified
setup
is
eventually
deleted,
the Factory setup is restored to its original form.
SS
GE
PC88 Service Manual
1-4

Chapter 1 Basic Operation
Zone Parameters
To the right of the LCD are two rows of six buttons.
The top row is used to access parameters within each of
the four zones for a Setup. The bottom row is used for
controlling Setup parameters, global settings and memory
functions. Each button in the bottom row opens up a list
of parameters.
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The Global button is especially important to servicers.
Entering the Global menu will allow you to save the
customer's setups, reset the PC88 and enter MIDIScope. It
will also allow you to check the available memory and
"All Notes Off" command, etc.
Zone Select and Assignable Controllers
To the left of the LCD are the four Zone buttons,
labelled 1 through 4. The Zone buttons 1 through 4 are
only operative in the MIDI Setups mode. When you are
in the Internal Voices mode, only Zone 1 is used.
Zone 1 Zone 2 Zone 3 Zone 4 Solo
PC88 Service Manual
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Chapter 1 Basic Operation
Each button has a three color LED. A green LED is lit
when the zone is on or active, an orange LED when it is
muted and a red LED when it is being soloed.
The Solo button to the right of the Zone buttons mutes
all zones except the current one. Pressing the Solo button
will turn the Zone button'’s LED red indicating that the
zone is being soloed.
Located beneath the Zone buttons are four sliders
labelled A through D and three buttons, labelled E, F and G.
These sliders and buttons along with the two wheels to
the left of the keyboard can all be assigned to different
MIDI functions. The buttons can be designated to work as
momentary as well as on/off.
The sliders, buttons and wheels are shipped from the
Factory with default settings. However, they are all
assignable on a per zone basis. They not only have the
capability of doing different things in different setups, they
may also do different things within a setup.
Data Entry
The Data Entry section contains the Alpha Wheel, the
Decrement/Increment buttons and the Numeric Keypad.
STU
YZ
Space
VWX
0-9
UPPERAower
_ +
The Alpha Wheel is used to quickly move through
voices and setups. In the Parameter mode, you can
quickly move through parameters.
PC88 Service Manual
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Chapter 1 Basic Operation
The decrement/increment buttons complement the
Alpha Wheel. Once you are in the vicinity you need to
be, the decrement/increment buttons allow you to make
small adjustments. In Parameter mode, pressing both
buttons simultaneously will bring you back to the default
setting.
The Number keypad is useful when you know exactly
what voice, setup or parameter you wish to choose.
Simply press the numbers you want and press Enter.
The Enter and Cancel buttons also act as Yes and No
for when the display asks you a question.
The +/- button is used to enter negative numbers.
When entering program numbers, it is also used to add a
separator between the bank and program numbers.
As you can see, the numeric keypad can also be used as
an alphabetical keypad. This is used to name setups.
Master Volume
The Master Volume Slider is located at the far left end
of the control panel. It controls volume for the main
outputs and the headphones. The Master Volume is not
programmable and and does not generate MIDI Volume
commands or data.
Panic Button
The Panic button is located to the left of the Alpha
Wheel.
Pressing the Panic button basically stops all sound
produced by the PC88 and any other MIDI device
connected to it. It also sends "All Notes Off" and "Reset
All Controllers" MIDI messages on all 16 MIDI channels.
PC88 Service Manual
1-7
a ES
on

Chapter 1
Basic Operation
Effects
The three Effects buttons located beneath the Panic
button control the following:
Effects
Wl Room MB Bright mm Chorus 1
GH Stage WE Normal @ Chorus 2
7 tel GB Warm ME Delay
The first Effects button selects the type of the Reverb:
Room, Stage, or Hall You will see the LED light up as you
select the variations. Reverb is off, when no LEDs are lit
The second Effects button controls the tone of the
Reverb: Bright, Warm or Normal. You will see the LED
light up as you select the variations. Reverb is off when
no LEDs are lit.
The third Effects button selects the Chorus or Delay
effect: Chorus 1, Chorus 2 or Delay. You will see the LED
light up as you select the variations. Reverb is off when
no LEDs are lit.
PC88 Service Manual
1-8

Chapter 2 Diagnostics
Diagnostic Tests
The following lists the sequence of tests in the PC88
Diagnostic Test Modes. These tests are available in all test
modes with the exception of the Sound Mode. The VGM
Port Test and Sound Test are the only tests available in
Sound Mode.
CPU Test
Program ROM Test
RAM Test
NVRAM Test
MIDI UART Test
Scanner Test
Parallel I/O Test
Timer Test
Homer Test
Sound ROM Test
Marge Test
Delay RAM Test
LCD Test
VGM Port Test
Sound Test
Scanner Tests
The Scanner Tests allow you to individually check the
Keyboard keys and pressure, Front Panel buttons, LEDs,
sliders, and Data Wheel, Mod Wheels and Rear Panel
jacks. The result of each test is noted in the LCD. The
Scanner Tests begin on Page 2 - 14.
PC88 Service Manual
2-1

Chapter 2 Diagnostics
Entering Diagnostics
Important: All user setups should be saved prior to
entering any diagnostic mode. If you have a sequencer or
computer, you should save the customer's setups so that
they can be reloaded after the Diagnostic Tests are exited.
Press the Global button to enter the Global menu and step
through the selections until you reach Dump all Setups?
Select Enter.
To enter the PC88 Diagnostics, apply power to the PC88
while simultaneously holding down the 1,2 and 3
buttons. As soon as power is applied, immediately release
the 1,2 and 3 buttons. Continuing to depress the buttons
may cause the unit to simply sit there with a blank screen.
You should see the following in the LCD.
a Press <<< to Reset..
Press >>> for Diags.
Press the >>> button, which will enter diagnostics.
PC88 Service Manual
2-2