Tandy 6000 HD User manual

TANDY®
Service Manual
TANDY
6000/6000 HD
Catalog Number 26-6021/2
CUSTOM MANUFACTURED FOR RADIO SHACK, A DIVISION OF TANDY CORPORATION
26-6021/2

TANDY COMPUTER PRODUCTS
SERVICE MANUAL
TANDY® 6000/6000-HD
Catalog Numb r 26-6021/2

TANDY COMPUTER PRODUCTS
TANDY® 6000/6000-HD S rvic Manual
Copyright 1985 Tandy Corporation
All Rights R s rv d
R production or us , without xpr ss writt n p rmission from
Tandy Corporation, of any portion of this manual is
prohibit d. Whil r asonabl fforts hav b n tak n in th
pr paration of this manual to assur its accuracy, Tandy
Corporation assum s no liability r sulting from any rrors
or omissions in this manual, or from th us of th
information contain d h r in.

TANDY COMPUTER PRODUCTS
Cont nts Pag No.
1/ Introduction ........................................... 1
2/ T chnical Sp cifications .............................. 7
3/ Disass mbly/Ass mbly Proc dur s ...................... 9
4/ Adjustm nts ........................................... 19
5/ Cabling Diagrams/Pin D signations ................... 23
6/ Troubl shooting Proc dur s ........................... 47
7/ Th ory of Op ration
7.1 Moth r Board ................................ 55
7.2 MC68000 CPU B o a r d ........................... 61
7.3 M mory Board ............................... 103
7.4 Main Logic Board ........................... 121
7.5 Vid o/K yboard Int rfac Board ........... 165
7.6 Pow r Supply Board ......................... 193
7.7 Sound B o a r d ................................ 209
7.8 CRT Ass mbly ............................... 213
7.9 K yboard Ass mbly .......................... 215
7.10 Hard Disk Controll r ...................... 219
8/ Explod d Vi ws/Parts Lists .......................... 243
8.1 Bas Ass mbly ............................... 244
8.2 Card Cag , Chassis
and Pow r Supply ........................... 246
8.3 Floppy Disk Driv .......................... 248
8.4 Hard Disk Driv Ass mbly ........ 250
8.5 B z l Ass mbly .............................. 252
8.6 R s t/Pow r On Indicator Modul .......... 254
8.7 Cas Top ................................... 256
8.8 K yboard Ass mbly .......................... 258
App ndic s
Vid o Monitor Ass mbly ............................. 263
Floppy Disk Ass mbly (Tandon) ....... 269
Hard Disk Ass mbly (Tandon) ......................... 36 9

TANDY COMPUTER PRODUCTS
List of Figur s
Numb r D scription Pag No.
1-1 Major Ass mbli s, TANDY 6000/6000-HD ......... 2
3-1 Cov r/B z l Ass mbly Mounting Scr ws ........ 10
3-2 El ctronics Modul Ass mbly .................. 15
4-1 Adjustm nts ................................... 20
5-1 Cabl Int rconn ction Layout ................. 23
5-2 Cabl Wiring/Conn ctor Location
Floppy Disk Driv V rsion 1 ............... 25
5-3 Cabl Wiring/Conn ctor Location
Hard Disk Driv V rsion 1 ................. 27
5-4 Cabl Wiring/Conn ctor Location
Floppy Disk Driv V rsion 2 ............... 29
5-5 Cabl Wiring/Conn ctor Location
Hard Disk Driv V rsion 1 ................. 31
5-6 RS-232 S rial Int rfac Cabl ............ 34
5-7 Lin Print r/Parall l Output Cabl .......... 34
5-8 FDC to Int rnal Driv Cabl .................. 36
5-9 Vid o/K yboard PCB to K yboard Cabl ........ 37
5-10 DC Pow r Cabl ................................ 38
5-11 AC Input Cabl ................................ 39
5-12 Main Logic Board to Sound Board Cabl ....... 40
5-13 Vid o Cabl ................................... 41
7-1 R ad and Writ Cycl Timing .................. 69
7-2 Writ Cycl Timing ............................ 70
7-3 R ad Cycl Timing ............................. 71
7-4 R fr sh Cycl Timing of 68000 ................. 72
7-5 Bus Arbitration Circuit Timing ............... 77
7-6 Onboard BDTACK G n ration .................... 78
7-7 I/O Controll r Timing ......................... 81
7-8 Timing for R fr sh Logic ..................... 84
7-9 I/O Proc ssor PCB Block Diagram ............. 122
7-10 Vid o/K yboard Int rfac .................... 166
PCB Block Diagram
7-11 Timing D ia gram ............................... 168
7-12 MC6845 Pin Id ntification ................... 170
7-13 Charact r Dot Patt rn ........................ 173
7-14 K yboard Timing Diagram ...................... 180
7-15 T st Layout, Pow r Supply ................... 197
7-16 Q7 Coll ctor Wav form ........................ 199
7-17 Q7 Bas Wav form ............................. 199
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TANDY COMPUTER PRODUCTS
8-1 Explod d Vi w, Bas Ass mbly ............... 244
8-2 Explod d Vi w, Card Cag , Chassis,
and Pow r Supply ............................. 247
8-3 Explod d Vi w, Floppy Disk Driv ........... 249
8-4 Explod d Vi w, Hard Disk Driv Ass mbly .... 251
8-5 Explod d Vi w, B z l Ass mbly .............. 253
8-6 Explod d Vi w, R s t/Pow r On
Indicator Modul ............................ 255
8-7 Explod d Vi w, Cas Top Ass mbly ........... 257
8-8 Explod d Vi w, K yboard Ass mbly .......... 259
List of Tabl s
Numb r D scription Pag No.
7-1 Int rrupt Inputs .............................. 66
7-2 M mory-Mapp d I/O Locations .................. 80
7-3 M mory Map of th MD68000 Subsyst m ........... 82
7—4 M mory Map S l ct Tabl s ..................... 105
7-5 Input/Output Port Map ....................... 125
7-6 M mory Map ................................... 128
7-7 Jump r Options ............................... 130
7-8 Port Addr ssing .............................. 176
7-9 Pow r Supply Voltag Chart .................. 197
7-10 Voltag and Rippl Sp cifications .......... 200
7-11 Port D coding ................................ 220
7-12 Ports and Functions ..... ...................... 220

TANDY C MPUTER PR DUCTS

S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
1/ Introduction
Th TANDY 6000/6000-HD Microcomput r is a pow rful
disk-bas d d sk-top busin ss comput r with many advanc d
f atur s. Th s f atur s includ portabl softwar , 512K of
m mory xpandabl to 1M, d tachabl typ writ r-format
k yboard with num rical k ypad and 8 programmabl function
k ys, gr n CRT Monitor scr n, and on parall l and two
s rial ports for xt rnal conn ction to a vari ty of
print rs and communications links.
Optional f atur s includ an xt rnal floppy Disk Bay
Expansion Unit (1-driv unit or 2-driv unit), a 15 M gabyt
or larg r Hard Disk Syst m for mass storag , an ARCNET™
syst m for local ar a communications n twork, a graphics
board for vid o graphics capability, and a multi-t rminal
int rfac board.
This manual is int nd d as a guid to assist in th
diagnosis of syst m probl ms to th subass mbly l v l. It
contains d tail d instructions on disass mbly and ass mbly
of major subass mbli s as w ll as som troubl shooting hints
for th PCBs and subass mbli s contain d in th syst m. It
also includ s a s ction on th th ory of op ration that
d scrib s board op ration and som individual compon nt
functions. It do s not, how v r, provid a compon nt by
compon nt analysis of th syst m.
Th basic TANDY 6000 is suppli d with two floppy Disk Driv s
and fiv PCB ass mbli s; th TANDY 6000-HD is suppli d with
on floppy disk and on int rnal 15-m g hard disk. Two of
th PCB ass mbli s ar mount d in th El ctronics Modul ,
which is attach d to th Bas Ass mbly. Th s includ th
I/O Proc ssor PCB and th Pow r Supply PCB. Th Sound PCB,
is mount d insid th Bas Ass mbly at th l ft front
corn r. Th CRT Monitor PCB mount d on th Bas Ass mbly,
is th l ctronics for th CRT ass mbly. Th s v n slot
xpansion unit plugs into th I/O Proc ssor PCB, and th
16-bit CPU and m mory board plug into th xpansion unit
along with th Vid o/K yboard Int rfac PCB.
™ - Datapoint Corporation
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S rvic Manual TANDY 6000/6000-HD
---------------------------------------------------------------------- TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
Figur 1-1. Major Ass mbli s, TANDY 6000/6000-HD
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S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
A simplifi d xplod d vi w of th TANDY 6000/6000-HD (Figur
1-1) h lps locat major sub-ass mbli s as th y ar d scrib d
in th following paragraphs. Disass mbly proc dur s not d
in S ction 3 must b follow d in th ord r pr s nt d du to
th mounting locations of th individual compon nts.
Th major subass mbli s that compris th TANDY 6000/6000-HD
includ (1) th Bas Ass mbly, (2) th El ctronics Modul ,
(3) th RESET Switch/Pow r-On Indicator Modul with cabl
ass mbly, (4) th Disk Driv /Driv Support structur , (5)Top
Cov r Ass mbly, (6) th B z l/CRT Ass mbly, (7) Card Cag
Ass mbly, and (8) th K yboard Ass mbly. Th disass mbly of
ach of th s ass mbli s is discuss d in S ction 3. Car
should b x rcis d in handling plastic compon nts to
pr v nt scratching or marring of th surfac finish.
1.1 Bas Ass mbly
Th Bas Ass mbly consists of th mold d plastic bas , pow r
and signal I/O compon nt mounting brack ts, pow r ON/OFF
switch, and Sound PCB that is r sponsibl for g n rating an
audibl ton wh n k y closur is achi v d. Th oth r
ass mbli s of th TANDY 6000/6000-HD ar mount d to th Bas
Ass mbly. Th Bas Ass mbly has rubb r f t to prot ct th
surfac on which th TANDY 6000/6000-HD is plac d for
op ration.
1.2 El ctronics Modul
Th El ctronics Modul consists of a form d m tal chassis,
thr compon nt mounting brack ts, two print d circuit
boards, and a card cag ass mbly with thr additional
boards. It is mount d to th instrum nt Bas Ass mbly with
four scr ws that ar acc ssibl wh n th Top Cov r Ass mbly
is r mov d from th comput r. Wh n th s scr ws and th
l ctrical conn ctions to th ass mbly ar r mov d, th
El ctronics Modul may b r mov d from th Bas Ass mbly as
a unit. Th modul mounts th I/O Proc ssor PCB, th
Vid o/K yboard Int rfac PCB, 16-bit CPU/M mory PCBs, th
Pow r Supply PCB, and th pow r supply cooling fan. Thr
ribbon cabl s conn ct d to th I/O Proc ssor Board xit th
modul through a slot in th right sid of th chassis and
conn ct to th r ar t rminal input conn ctors or th disk
driv (s). Th Pow r Supply Ass mbly cov rs th front half
of th ass mbly. Th Moth r Board mounts v rtically in th
dg card conn ctor in th middl of th I/O Proc ssor
Board. It is rigidly support d by th card cag sh t m tal
at th r ar of th modul .
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S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
1.3 RESET Switch/Pow r-On Indicator Modul
Th RESET Switch/Pow r-On Indicator modul is mount d to th
Driv Support Structur and consists of th pow r ON/OFF
indicator, th RESET Switch, and cabl ass mbly. Th RESET
switch, wh n pr ss d, blanks th scr n and flash s th
command INSERT DISKETTE on th scr n. To r mov this
modul from th unit, it is n c ssary to first r mov th
Top Cov r Ass mbly. Wh n r installing th ass mbly, it must
b prop rly position d with r sp ct to th B z l/CRT
Ass mbly cutout.
1.4 Driv Support Structur
Th Driv Support Structur is a rugg d, form d sh t m tal
d sign that is attach d to th Bas Ass mbly with six
mounting scr ws. Its d sign p rmits circulating air flow to
th disk driv s for improv d p rformanc . It contains
shi lding to prot ct th floppy disk driv l ctronics from
RF int rf r nc by th switching pow r supply or vid o
display. It mounts two slim lin floppy Disk Driv
ass mbli s (TANDY 6000), or on slim lin floppy Disk Driv
and on 15 M gabyt Hard Disk (TANDY 6000-HD). Th 6000-HD
is suppli d with on floppy disk and On hard disk.
1.5 Top Cov r Ass mbly
Th r ar thr mounting scr ws on th right sid of th
cas , thr on th l ft, on in th back that mount th Top
Cov r to th Bas .
Onc th s ar r mov d, th Top Cov r Ass mbly may b tilt d
up and lift d off th Bas Ass mbly.
1.6 B z l/CRT Ass mbly
Th B z l/CRT Ass mbly is a mold d plastic cov r that
contains th cathod ray tub (CRT). Th CRT monitor PCB and
associat d hardwar ar mount d to th bas . Th B z l/CRT
Ass mbly is attach d to th bas with mounting scr ws that
ar acc ssibl from th und rsid of th unit.
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S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS --------------------------------------- ------------------------------
CAUTION
Th cabl s b tw n th Vid o/K yboard Int rfac
PCB, Pow r Supply and th Monitor PCB ar short and
may b damag d if car is not x rcis d during
th ir r moval. Ex rcis car to pr v nt damag to
th compon nts mount d to th Bas Ass mbly. Do not
drop or oth rwis mishandl th B z l/CRT Ass mbly
as th CRT may implod , causing harm to p rsonn l
and compon nts.
Plug-in conn ctors attach th B z l/CRT Ass mbly
l ctrically to th Bas Ass mbly. To d tach th B z l/CRT
Ass mbly compl t ly, disconn ct th s conn ctors. Handl
th ass mbly car fully to pr v nt scratching or marring th
B z l surfac .
Th Vid o Monitor PCB forms th Vid o Monitor Ass mbly for
th TANDY 6000/6000-HD. Th Vid o Monitor PCB is mount d on
th insid on th Bas Ass mbly. Signal and pow r cabl s
int rconn ct it with th Vid o/K yboard Int rfac PCB and
Pow r Supply Ass mbly on th El ctronics Modul .
Th R ar Door Ass mbly is a r movabl ass mbly that allows
asy acc ss to th r ar compartm nt and card cag (wh n
install d). It slid s into a groov at th top of th
B z l/Cov r Ass mbly and is attach d to th Bas Ass mbly by
two thumb scr ws that s cur it at th bottom.
1.7 K yboard Ass mbly
Th K yboard Ass mbly is m chanically s parat from th
Bas /B z l/Cov r Ass mbly and is l ctrically conn ct d
through a 5-pin DIN conn ctor locat d on th front low r lip
of th Bas Ass mbly. Th two units ar conn ct d by a
coil d cabl ass mbly attach d to th K yboard Ass mbly that
allows it to b mov d up to 3 f t away from th Bas
Ass mbly. A strain r li f bushing provid s prot ction for
th signal cabl to pr v nt accid ntal pullout of th cabl
from th K yboard Ass mbly. Th k yboard is a thin-lin
d sign with standard typ writ r k y pad and num ric k y pad.
Contain d as part of th num ric k y pad s ction ar ight
function cod buttons, Fl through F8, which allow
application d p ndant programmabl functions to b s l ct d.
Cork f t provid prot ction for th mounting surfac on
which th K yboard Ass mbly is mount d.
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S rvic Manual TANDY 6000/6000-HD
---------------------------------------------------------------------- TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
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S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
2/ T chnical Sp cifications
2.1 Physical Charact ristics
2.1.1 Cas /B z l/Bas Ass mbly
Width 21.0 inch s (53.3 cm)
H ight 13.5 inch s (34.3 cm)
D pth 20.5 inch s (52.1 cm)
W ight 49.9 pounds (22.5 kgm)
2.1.2 K yboard
Width 18.0 inch s (45.7 cm)
H ight 2.5 inch s (6.4 cm)
D pth 7.5 inch s (19.1 cm)
W ight 3.3 pounds (1.49 kgm)
2.2 Syst m Op rating Charact ristics
Min Typ Max Units
Ambi nt T mp ratur 55 75 85 D gr F
12 23 30 D gr C
Voltag Rang (USA) 95 115 135 VAC
(Europ ) 190 230 270 VAC
Curr nt Drain
--
1.5 2.0 A
Lin Fr qu ncy 47 50/60 63 Hz
2.3 P riph ral Int rfac s
S rial Int rfac
Chann l A allows asynchronous or synchronous communica
tion .
Chann l B allows asynchronous communication only.
Both chann l A and B conform to th RS-232C Standard
Both us DB-25 conn ctors on th back of th display
consol . Pin-out conn ctions ar shown in S ction 5,
Cabl Wiring/Pin D signations.
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S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
Parall l Int rfac
Conn cts to a lin print r via th 34-pin conn ctor on
th back of th display consol . S S ction 5, Cabl
Wiring/Pin D signations.
Outputs 8 data bits in parall l. Inputs 4 data bits.
All l v ls ar TTL compatibl
Multi-Slot Card Cag
Provid s four additional slots to accommodat hard disk
driv int rfac , graphics board, ARCNET board,
multi-t rminal int rfac board.
Disk Bay Expansion Unit
Optional xtra unit contains ith r on or two disk
driv s, 8" floppy disk tt , 500K byt storag p r
disk tt (singl sid d, doubl d nsity or 1 m gabyt
with doubl sid d, doubl d nsity).
16-Bit CPU Board
Provid s 16-bit op ration for high-l v l languag tasks.
Hardwar allows 8 l v ls of v ctor d int rrupts, 4
l v ls of fix d priority bus arbitration, a Z80 to
MC68000 m mory int rfac controll r, and dir ct acc ss
for up to 7 m gabyt s of m mory. Softwar supports only
a l v l 5 int rrupt. Softwar supports 1 M gabyt of
m mory.
Th main compon nts of this board ar th MC68000 CPU
and th AM9519A Int rrupt Controll r.
512K-Byt , 16-Bit M mory Board
Off rs optional byt parity ch cking and d t ction
logic and s l cting to map m mory on any 256K boundry
within 7-M g m mory spac . 1 m gabyt of m mory is
support d by softwar . Oth r chip locations ar only
scr n d on th board and sock ts ar n't install d.
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S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
3/ Disass mbly/Ass mbly Proc dur s
Th TANDY 6000 Microcomput r is d sign d for tabl -top
op ration. Dim nsions of th main housing ass mbly and th
k yboard ass mbly ar giv n in T chnical Sp cifications,
S ction 2. A d sk ass mbly may b us d that allows mounting
of optional xtra disk driv s us d with th TANDY
6000/6000-HD syst m. Ad quat spac should b l ft around
th unit to allow suffici nt air flow to all compon nts.
If th TANDY 6000 has th fan nclos d in a m tal housing on
th back of th acc ss pan l you n d to follow th
disass mbly and ass mbly instructions in th Mod l 16B
S rvic Manual (S Figur s 5-2 and 5-3). Oth rwis , follow
th disass mbly and ass mbly instructions contain d in th
following proc dur s (S Figur s 5-4 and 5-5). Ex rcis
car in handling th Top Cov r and B z l/CRT Ass mbli s to
pr v nt scratching or marring th surfac finish.
3.1 Top Cov r Ass mbly
1. R mov all pow r from th unit by disconn cting th
pow r cord. R mov p riph ral cabl s (if r quir d).
2. R mov from th disk driv s, th cardboard ins rts that
prot ct th driv during shipm nt. (Sav for lat r us .)
3. Plac th unit upsid down on a smooth, padd d surfac
to pr v nt scratching th paint d surfac s.
4. R mov s v n (7) scr ws that attach th Top Cov r
Ass mbly to th Bas Ass mbly. Th r should b thr
scr ws on th right sid , thr scr ws on th l ft, and
on scr w at th r ar. S Figur 3-1, which shows th
location of th scr ws.
5. Hold th two ass mbli s tog th r and turn th unit
rightsid up.
6. R mov th R ar Acc ss Door by r moving th two scr ws
at th bottom and pushing down and out on th door.
7. Lift up th r ar of th top cov r and angl it towards
th front pan l, th n lift th top cov r away from th
bas ass mbly.
8. Onc th Top Cov r Ass mbly is cl ar, lay it off to th
sid .
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S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS -------------------------------------------------------------------- --
Figur 3-1. Cov r Ass mbly and B z l Ass mbly
Mounting Scr ws
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S rvic Manual TANDY 6000/6000-HD
TANDY COMPUTER PRODUCTS ---------------------------------------------------------------------
3.2 B z l/CRT Ass mbly R moval
1. Loos n th thr (3) scr ws at th front of th unit
that attach th B z l/CRT Ass mbly to th Bas Ass mbly.
S Figur 3-1, which shows th location of th s
scr ws.
2. R mov th two (2) scr ws, at th top of th Driv
Support Structur , which attach th B z l/CRT Ass mbly
support bar to th Driv Support Structur .
3. R mov th two (2) scr ws, at th l ft of th unit,
which attach th CRT Monitor PCB Brack t to th Bas
Ass mbly.
4. S parat th two units (Bas and B z l/CRT) by
disconn cting th attaching harn ss s (on to th
Vid o/K yboard Int rfac PCB and an in-lin conn ctor to
th Pow r Supply Ass mbly).
5. R mov th ground wir spad lug t rminal from th CRT
Monitor PCB. This compl t ly s parat s th B z l/CRT
Ass mbly from th Bas Ass mbly.
3.3 CRT R moval
1. Disconn ct th tub sock t from th r ar of th CRT.
2. Disconn ct th d fl ction coil wir conn ctor at th CRT
Monitor PCB.
CAUTION
Mak sur th high voltag is discharg d
from th CRT (us ground d scr wdriv r
to discharg ).
3. Disconn ct th high voltag clip.
4. Disconn ct th in-lin conn ctor which attach s th CRT
Monitor PCB to th ground wir around th r ar of th
CRT.
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S rvic Manual TANDY 6000/6000-HD
--------------------------------------------------------------------- TANDY COMPUTER PRODUCTS ----------------------------------------------------------------------
5. R mov th two l ft mounting nuts and wash rs that
attach th CRT Monitor PCB brack t to th B z l/CRT
Ass mbly and r mov th brack t and board from th
ass mbly.
6. R mov th oth r two nuts and wash rs from th CRT.
Car fully lift th CRT from th B z l/CRT Ass mbly.
CAUTION
Handl th CRT v ry car fully to pr v nt
injury du to CRT implosion. Do not
handl tub using th n ck of th tub .
ALWAYS USE GOGGLES OR SAFETY GLASSES.
7. Ass mbl th B z l/CRT Ass mbly in th r v rs ord r of
disass mbly. Mak sur that th grounding wir from th
El ctronics Modul is conn ct d to th lug on th CRT
Monitor PCB low r r ar mounting scr w.
3.4 Brightn ss and Contrast Controls
1. Th brightn ss and contrast controls ar acc ssibl
aft r th B z l/CRT Ass mbly has b n r mov d from th
Bas Ass mbly.
2. R mov ith r control by first r moving th knob
attach d to th POT shaft.
3. R mov th conn ctor from th pot, noting th mann r in
which th conn ctor is mount d. Th conn ctor is not
k y d, so it would b possibl to put it on backward
wh n r ass mbling. Th numb rs on th conn ctor should
b down and not abl to b r ad.
4. R mov th attaching nut and slid th control off th
brack t.
5. Th brightn ss control (500K ohms) is to th front of
th ass mbly, contrast control (500 ohms) is to th
r ar.
6. R ass mbl in th r v rs ord r, making sur th knobs
ar fully push d onto th pot shafts to align with th
cutout slots in th Bas Ass mbly.
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