Chassis Anubis a Ac v1 2

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Co lour Televis ion

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Service

Chassis Anubis A

Contents

1. Introduction

2. Operation

3. Channelselectorand intermediatefrequencycircuit

4. Audio path

5. Video path

6. Synchronisationand deflection

7. Powersupply

Publ ished by Con sumer E le ct ro n ic s P rin te d I n T h e Ne th e rla nd s c C o py rig ht r es er ve d S u bje ct to modif icat ion @4822 727 18321

CS35687GB



6603

- 1. Introduction

T he A nu bis A ch as sis is a n ew ch as sis fo r s ma ll-s cre en co lo urte le vis io ns w ith a p ictu re s ize o f 1 4", 1 5" a nd 1 7".T he A nub is A has b ee n de ve lo pe d a s th e s ucce ss or to th em o n o c ha ss is w ith o ut te le te xt G 90AE a nd G 90B. A ll c irc uits a re

lo c ate d o n o n e m o n o bo a rd . T his m o n o bo a rd is m o d ula r, w hic hm e an s th at a ll fu nc tio n al c om po n en ts o f o n e c erta in c irc uit a rep OS itio ne dclo se to o ne a no th er in o ne s ubmo du le o n th em o n o bo a rd (s ee F ig . 1.1).Th is , to g e th er w ith th e "Se rv ic e D e f au lt M o d e ", " Erro rm e ss ag es " a nd th e "T es t p o in ts ", e na ble s fa st d ia gn o sis a ndth ere fo r e g o o d s erv ic e. D e p e nd in g o n th e h ardwa re v ers io n ,th e fo llow in g s ys tem c omb in atio n s a re p o ss ib le :

SYSTEMS

-P AL I-PAL BG SECAM BG-P AL BG S EC AM BGLL'-P AL B GI S EC AM BGLL'

O PT IO N D IO D E

66046605

US i.n gth e o p tio n d io d e s th e m ic ro c ompute r c an b e " to ld " w h ic hs ys tem s th ~ u nit is s uita ble fo r.T he A nu bis A is e qu ip pe d w ith m e nu o p era tio n : a n in sta lla tio nm e nu fo r a utom a tic tu nin g, s ys tem s ele ctio n a nd th e s to ra ge o fth e v ario u s d ata a nd th e b rig htn es s, c o ntra st a nd c o lo u rs atu ra tio n m en u. T he m en us ca n b e ca lle d u p u sin g th ere le va nt k ey s (s ee F ig . 1 .2 ).

1 .1 Repair fac ilities

S ervice D efault M od e

T he A nu bis A c ha ss is is e qu ip pe d w ith te st p o in ts , T P1 , T P 2,e tc . in th e s erv ic e in stru ctio n s o n th e c om po n en ts ' s id e o f th emonoboa rd .U sin g th es e te st p oin ts it is p os sib le to s et a qu ick d ia gn os is o nthe to p o f the m o no bo ard . .T he se te st p oin ts ca n a ls o b e fo un d in th e S erv ice M an ua l.

T he A nu bis A s o ftw are a ls o c o nta in s a "S erv ic e D e fa ult M o d e".T o a ctiv ate th is m o d e th e s erv ice p in o f th e m ic ro c om pu te r (p in7 -7 60 0) s ho u ld b e s ho rt-c irc uite d to e arth w he n th e u nit is

s witc he d o n w ith th e ma in s switc h.

A n "S " appears o n the screen w hen the un it is in the S erv iceD e f au lt M o d e.If th is m o de has been activa ted , the un it is in a defined m o de inw hich a ll fu nctio ns a re in th e m id p os itio n a nd th e u nit is tu ne dto p ro gra mm e n um be r 1 .It is p o ss ib le to e xit from th e S erv ic e D e fa ult M o de b y switc hin g. th e u nit o ff u sin g th e m ain s s witch o r th e re mo te co ntro l.

Test polnts

/

CS 35 688 GB



-rro r messages The m icro co mputer a lso co nta ins an 12C (In te r IC bu s) s oftw are

erro r detec tio n w hich ind ica tes erro r m essages in a certa in

c ircu it by m eans o f the aso (On Screen D isp lay) and a

fla sh in g L ED .

FMSOUND

EUROCONNECTOR

Fig. 1.1

0 [ ] [ ] n [ ] o [ ] [ ] [ ]POWER 1 2 3 4 5 6 7 B

N OR MA L U SE

key function

1 program -

2 program +3 v olu me -4 vo lume +

5 install menu

6 ~ ~ ~ ~ n : / ~ ~enuI--

7

8 0500"/011

INSTALL MENU BRIGHTNESS MENU

key function key function

1 program - (stop searching) 1 program -

2 p ro gra m + (stop searching) 2 p ro gra m +3 v olume - 3 vo lu me -4 volume + 4 volume +

--- 5 store PP ( ba ck to norma l u se) 5

-system 6 con tras t menu -search 7 br ig htn ess -

8 store tuning reference 8 brightness +( ba ck t o norma l u se )

C ON TR AS T M EN U

key function

1 progr~m -2 program +3 v olu me -

Fig . 1.2 4 vo lume +5 -

colour menu r--7 con tr as t -

8 contrast +

I-

C OL OU R M EN U

key function

1 program -

2 program +

3 v o lu m e -4 vo lume T

5 -6 norma l use r-7 colour -

8 co lou r +

CS 35 689 GB

MOA02858

T-26/044



1.2 The b lo c k d ia g r a m

O n the A nu bis A a ll c ircu its w ith the e xcep tio n o f th e R GBo u tp ut am plifie rs a re in te gra te d o n o n e p an el, th e c ha ss is .T he fu nc tio n al b lo cks o n th e c ha ss is c o rre sp on d to th e b lo c ksin th e b lo ck d iagram (F ig . 1.3). T he na me s a re a lso to be fo un do n th e c ha ss is in th e s erv ic e in stru ctio n s.

Tuner Channe l se le c to rA t p o sitio n 1 00 1 th ere is th e c ha nn el s ele cto r, a U V9 17 fo rV HF -UHF -S re ce ptio n o r a U 74 3 fo r U HF re ce ptio n o nly .T he c ha nn el s ele cto r is tu ne d a cc o rd in g to th e VST p rin cip le .IC 7 00 2 (LA7 91 0), a th re e-o u t-o f-tw o d ec o de r, is u se d fo r b an dswitching.

IF/SYNC IF /synchron isa t ionIC 7015 (TDA4504 ) c o n ta in s th e in te rmed ia te fr equ en cyamp lifie r, in te rmed ia te fr equ en cy d e te c to r . v id e o sw itc h a n d th e

synch ron isa ti on c ir cu it s .

Chroma Chrom inanceT he c hro m a m o du le c o ns is ts o f IC 72 50 (T D A 46 50 ). am u ltis ta nd ard c o lo u r d ec o de r, o r IC 7 26 0 (T DA451 0), a PALc o lo u r d ec o de r, IC 7 22 1 (T DA466 0), th e b as eb an d d ela y lin e,a nd IC 72 80 (T D A 35 04 ), th e v id eo c o ntro lle r IC . T he RGBo u tp ut am plifie rs a re lo c ate d o n th e p ic tu re tu be p an el.

T he h orizo nta l o u tp ut s ta ge is fo rm e d b y tra ns is to r 7 44 5 a ndth e lin e o u tp ut tra ns fo rm e r 5 44 5. T he h o riz o nta l o u tp ut s ta ges up plie s th e h ig h v olta ge a nd th e fo c us in g v o lta ge a nd a ls o

s up plie s th e + 16 3V , + 5B , + 13 a nd + 26 v olta ge s.IC 7 40 0 (T DA365 3) is u se d fo r th e v ertic al d efle ctio n .

Deflection

AM de te cto r Filte rs 510 4 an d 510 6 fo rm a ban dpas s fo r the AM m o dula te dso und w ith S EC AM LL ' and th e AM de te ctio n ta kes p lac e inIC7215 (TD A3843 ).

FM sou nd IC 71 35 (T D A 38 27 ) is u se d fo r d em o du la tio n o f FM m o du la te dso und . T his IC is a ls o used fo r sw itch ing betw een AM, F M o ra ud io c om in g from th e e uro c o nn ec to r.IC 7 15 7 (T DA70 52 ) is fo r th e a ud io o u tp ut am plifie r.

ControlsT he c on tro l is b y m ea ns o f m ic ro c om pu te r IC 77 20

(TMP47C434). "

Powe r supp ly The ma in s -is o la te d p owe r 's u pp ly c o n sis ts o f tr an sis to r 7 525a nd tra ns fo rm er 5 52 5 a nd is o f th e SOPS (S elf O sc illa tin gP o we r S up ply ) ty pe . T he p ow er s up ply s up pli~ s th e + 95 V, + 9a nd + 5A v o lta ge s.

Euro Euroconnec t o rT he A nu bis A is e qu ip pe d w ith a E uro (s ca rt) c o nn ec to r.

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2. Operation

A ll o pera ting and co ntro l functio ns are lo ca ted in the

C ON TR OLS subm o du le (F ig . 2 .1).

The cen tra l pa rt o f the o pera tio n is a 42-p in C -M OS

m icro co m pu te r IC 7600 o f ty pe T M P47C 43 4.

Operatin g keys There are 8 o pera ting keys and an RC5 rem ote co ntro l fo r the

o pera tio n is ava ilab le as a n o ptio n.

The 8 keys are co nnected in a m atrix to p in s 10 to 13 o f the

m icro co mpute r and are read eve ry 16 m sec . The g iven

co mm and can be de te rm ined by g iv ing o ne o f the p ins a "lo w"

level and read ing the o the r p ins whe ther they a re "lo w" o r no t.

The co m mands transm itted by the rem o te co ntro l a re rece ived

by the in fra red rece ive r 1685 and transm itted to p in 35 o f the

mic rocompute r .

The o ptio n d io de be tween p in 8 and p in 14 is used to

de te rm ine w hether the un it is equ ipped fo r rem o te co ntro l(d io de p rese nt) o r n o t (d io de no t p rese nt).

Vario us sw itch ing vo ltages are p resen t o n p ins 36, 37 and 38

and these are needed in the un it fo r sys tem sw itcho ve r (see

ta ble 1). T he sw itch in g tra ns is to rs in ve rt th e sw itc hin g v o lta ge

and se t it to the co rrect leve l.

System sw itc hin g

voltages

BG /L - UL' • PAL I

P IN IC 760 0

SYSTEM UL' BG /L PALl

36 37 38

UHF o n ly L L H

BG L L L

L L H L

L' H L L

Tab le 1

By m eans o f the o ptio n d io des o n p ins 10 , 11, 12 and 14 , the

m icro co m pute r rea ds the sys tem fa cilitie s o f the un it d uring the

in it ia lis a tio n p ha se .

PAL I (UHF o n ly) 6603

PAUSECAMBGLL' 6604

PAUSECAM BG ILL ' 6605

O n S creen Disp lay

OSD

U sing the O SD genera to r, in fo rm atio n is g iven o n the sc reen

ab ou t the tune d ba nd, the po sitio n .in th e tun ing ra nge (tun ing

b ar), syste m se lecte d, s lee p tim er, p ro gram m e n um ber an d the

ad jus tm en t o f the va rio us p ic tu re and so und se ttings . In o rder

to synchro nise the O SD in fo rm atio n w ith the p ic tu re s igna l, the

CS 35 692 GB



_ t U M : ' " ,fram e flyback s igna l is added inverted to p ins 15 and 27 and

the sandcastle s igna l to p in 26.

The OSD fast b lanking s igna l is ava ilab le a t p in 25 and the

OSD pictu re s ignal at p in 23.

Memory The m icro co mputer is co nnected to a no n-vo latile m em ory

IC 7685 (E EPRO M) via the 12

C bus. The pre ference andpro gram me data are sto red in th is m em ory. The system has the

fac ility to s to re 40 (0 to 39) pre fe rred transm itte rs to ge ther w ith

the ir tun ing, band vo ltage and system data.

P icture and sound

settings

There are 4 analo g se ttings ava ilab le : vo lum e (p in 2),

brightness (p in 3), co lo ur sa turatio n (p in 4) and co ntrast (p in 5).

The R-C netwo rks are used to m ake a D C vo ltage leve l fro m

the pu lse width m o dula ted o utp ut s ig na l.

A certa in ad justm ent o f these se ttings can be prepro gram med

in the m em ory as perso na l prefe rence (PP).

S ound suppress io n (m ute) takes p lace in te rna lly in the

m icro co m pute r during the au to m atic transm itter search o r w henin te rrup ting a transm itter s igna l. T his is detected v ia the ID E NT

S igna l a t p in 16 o f the IC .

The tun ing system is o f the VST (Vo ltage Synthes ized Tun ing)

system type . This system is based o n the princ ip le that tuning

to a transm itte r in the un it is by m eans o f linear variatio n o f the

tun ing vo ltage (V vari) fo r the channel se lecto r. The tun ing

-.vo ltage (0 V2 to 5 V) is ava ilab le a t p in 1 o f the m icro co m pute r

and is set to the co rrect leve l (0 V to 33 V) us ing the +95.

The AFC (Auto matic Frequency C on tro l) wh ich is added to the

tu ning vo ltag e is sw itch ed o ff d urin g tra nsm itter se arch u sin g

p in 41.

If du ring the transm itte r search an ID EN T signa l is rece ived a tp in 16, the m icro co mputer w ill check v ia the inpu t p in 9 whether

the tun ing is co rrect and whether the AFC can be sw itched o n

again.

The m icro co mpute r has two sw itch ing vo ltages o n p ins 17 and

18 fo r b and sw itch in g.

Tuning

Power On R eset

POR

The frequency o f the o sc illa to r (4 M Hz) o f the m icro co mputer is

se t us ing a crysta l o n p ins 31 and 32.

In o rder to s tart up the m icro co mpute r p ro perly , as so on as the

unit is sw itched o n w ith the ma ins sw itch a POR (Power On

Re se t) p uls e ls g iven a t p in 33; T he in itia lisa tio n w ill take place

a nd th e m icro c om p ute r will sta rt u p.

Stand-by The stand-by sw itch ing signal is p resen t a t p in 19 o f the

m icro co m puter. U sing th is the m icro co m puter can sw itch the

po wer supp ly to the stand-by m ode (o nly po ss ib le if the un it

has a rem o te co ntro l).

The LED at p in 20 w ill be red in the stand-by m ode and w ill

flash during R C5 receptio n o r erro r m essages.



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- 3 . C h a n n e l s e l e c t o r a n d i n t e r m e d i a t e

f r e q u e n c y

Channe l se lec tor C hanne l se lecto r 1001 (F ig . 3 .1) is a U743 o r a UV917 . The

U743 is a channe l se lecto r o nly su itab le fo r recep tio n in the .

h igh band fo r the PAll system (see tab le 2).

The UV917 , fo r a ll o the r system s, is su itab le fo r recep tio n in the

lo w band, the m id band and the h igh band. In the case o f a

U V9 17 c ha nn el s ele cto r, IC 70 02 (L A7 91 0), a fo u r-o u t-o f-tw o

deco de r, is used fo r the band sw itch ing by m eans o f p ins 7,8

and 10 o f the channe l se lecto r {tab le 2}.

BAND IC7002 1001

3 4 7 8 10

U743 HIGH NOT L L H

PRESENT

UV917 lOW L l H l L

M ID H L l H l

H IGH H H l l H

Lo w b an d:

M id b an d:

H ig h b an d:

46 - 170 MHz (VHFI + S )

170 - 450 MHz (S + VHFII I )

450 - 861 MHZ (UHF)

Tabe l2

The tun ing vo ltage Vvari is supp lied v ia p in 11 and the AGC

(A uto m atic G ain C o ntro l) vo ltage v ia p in 5.

T he 38 .9 M Hz in te rm ed ia te fre quency s igna l is p resen t a t the

o utpu t p in 17 o f the channe l se lecto r (33.4 M Hz fo r a s igna l

acco rd ing to the S EC AM L' system ).

In termediate f requencybandpass

T he in te rm e dia te fre qu en cy b an dp as s c ha ra cte ris tic is

de te rm ined by the bandpass filte r 1015. A 5.5 M Hz SAW

{S urface Aco ustic W a ve} filte r is o nly used fo r P AUS E C AM BG

units .

In the case o f PAUSECAM BG ILL ' un its a 6 MHz filte r is used

fo r th e LL ' syste ms (sw itch ing S igna l BG /l "h ighn).If the sw itch ing s igna l BG /l is "lo w" (BG I sys tem s), the

33 .4 MH z b an dsto p filte r (50121201 4) is co n ne cte d in p ara lle l to

the inpu t o f the filte r and the bandpass is a t 33.4 M Hz -20 dB.

Fo r 1015 a filte r w ith a bandw id th o f 6 .0 M Hz is used fo r the

P AL I system .

CS 35 694 GB



100'UV917

U743

AF C

-emodulat ionAGC

The in te rm ed ia te frequency s igna l is supp lied to IC 7015 p ins 9

and 10. Th is IC is su itab le fo r bo th nega tive (BG ) and po sitive

(ll') m odu la tio n depend ing o n the sw itch ing s igna l a t p in 32.

T his sw itch ing s igna l a lso d ete rm ines w hether th e A Ge c ircu it

co ntro ls a t the to p w hite leve l (po sitive m o du la tio n) o r a t the to p

sy nc le ve l (n eg ative m o du la tio n). T he h ig h-fre qu en cy A GC

vo ltage is ava ilab le a t p in 6.T he takeo ver leve l o f the h igh-frequency (de laye d) AG C co ntro l

can be se t a t p in 2 by m eans o f 3021.

In co nnec tio n w ith an other in te rm ed ia te fre quen cy w ith th e

SECAM l' system (33.4 M Hz), it m us t be po ss ib le to sw itch the

dem o du la tio n re fe rence circu it 5040 a t p ins 23 and 24. Th is is

do ne by m eans o f the sw itch ing s igna l Ul'. If th is s ig na l is

"h igh", the co il 5043 w ill be co nnec ted in para lle l to 5040 and

the circu it is tuned to 33.4 M Hz.

Automatic f requency

control AFC

The AFC s igna l a t p in 21 is o bta ined fro m the re fe rence s igna l

and the co ntro l is m od ified in tem ally in the IC fo r po sitive o r

n eg a tiv e mo d u la tio n .

Source selec tion The baseband CVBS signa l is ava ilab le a t p in 20 w ith a

no m ina l am plitude o f 2 V . In mecasect "FM ( in ter car ri er )

so und" th is s igna l a lso co nta ins the 5.5 M Hz so und signa l.

The so und signa l is filte red o ut w ith a 5.5 MHz (6 .0 MHz PAL I)

c e ram i c f ilt er .

The CVBS signa l is no w fed back v ia p in 16 to the so u rce

se lec to r sw itch in the IC , w here us ing the s ta tus sw itch ing

s igna l a t p in 18 a se lectio n can be m ade between in te rna l

CVBS o r a CVBS s igna l fro m the eu ro co nnecto r. The CVBS

s igna l se lec ted is ava ilab le a t p in 15 .

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' . " 1 1 . : ' ' ' , _4. The audio path

There are tw o aud io pa ths: o ne fo r the BG system s, FM

m o du la ted in te rca rrie r so und , and o ne fo r the U L' system s, AM

m o d ula te d q ua si-s plit s o un d.

AM demodu la tion In te rfe rence s igna ls a t 30.9 M Hz are rem o ved fro m the

in te rm ed ia te frequen cy s ign al co m in g fro m the cha nne l se lec to r

b y th e filte r 210 2151 02 (F ig . 4 .1 ). V ia a filte r, 5104/5106, it is

added w ith a do ub le bandpass charac te ris tic to the AM

d em o du la tio n IC , IC 7125. T he d oub le ch arac te ris tic is

necessary because w ith the L sys tem the so und is a t 32.4 MHz

and w ith L ' a t 39.9 M Hz.

If the sw itch ing s igna l is "lo w" fo r the L sys tem , the d io des do

no t co nduct and the tun ing is de te rm ined by C 211 O . I f th e

sw itch ing s igna l is "h igh", the L ' sys tem , the tun ing is

d ete rm in ed b y C2110/211512120.

The dem odu la ted s igna l a t p in 6 is supp lied to the so urces ele ctio n s witc h in 1C 71 25 .

FM demodu la tion Fo r FM m o du la ted so und the so und s igna l is filte red th ro ugh

filte r 1135 o r 1136 fro m the baseband p ic tu re s igna l. O nly w hen

PAL Is se lecte d w ill the P AL Iw itch ing s igna l be lo w, 1136

pa ra lle l to 1135 and the bandw id th o f the filte r w ill beco me

6.0 M Hz. Th is sw itch ing s igna l a lso ensures tha t the

d emo d ula tio n c irc uit 513812138 o f IC 7135 is de tuned to

6.0 M Hz fo r P AL I; capacito rs 2174/2175 a re th en c on ne cte d

p ara lle l to th e filte r.

Fo r OK system s there is the o ptio n o f add ing a c ircu it

co nnected in se ries w ith 5138 so tha t the c ircu it is tuned to

6.5 M Hz.

Soundsystem select A fte r the de-em pha sis capac ito r 2148 th e dem o du la ted so und ,

p in 5 , is fed back to p in 6 o f the IC . The AM m o du la ted so und

m ay be a t p in 7 and w ith the vo ltage leve l a t p in 8 a se lec tio n

can be m ade between MUTE , FM o r AM so und.

V ia an am plifie r and a so urce se lectio n sw itch , cho ice be tw een

so und fro m the eu ro co nnec to r o r TV re ce ptio n , th e s ig na l is

supp lied to an ad justab le am plif ie r, w he re the vo lum e can be

ad jus ted us ing the vo ltage a t p in 16. W h en sw itch ing the un it

o n, the o utpu t s igna l a t p in 11is sh o rt-c ircu ite d to e arth top re ve nt s witc hin g n o is e.

Source selec tion

Volume contro l

IC 7157, th e o utpu t am plifie r IC , ha s a n om ina l o utpu t capa city

o f 1 watt .

CS 35 697GB



_ '4JM:ii4EUfO-cooneclor

~A G B25 1

r - - - - - - - - - - - - - - - - - - - - - - - - - ~ - - - - - - - - - - - - - - - - - - - , ~ ~ - - - - - - - - - - - - . ' - 2 - E - - - - - - - - - - - - - - - - - - ~

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20jJsec/DIV

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PRS06921

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CS 35 698

Fig~5.1



5. Video path

The C VBS signa l o rig inating fro m the v ideo so urce selectio n

sw itch (IC 7015-2A), see sectio n 3, is supp lied to IC 7250

(TD A4650) o r IC 7260 (TD A4510) v ia an inpu t filte r (F ig . 5 .1).

IC 7260 is o nly used in units which are su itab le fo r thereceptio n o f P AL signa ls , whereas IC 7250 is used fo r un its

wh ich can rece ive bo th PAL and SECAM signa ls .

L um inan ce p ath The C VBSsignal is filte red by the chro ma bandsto p filte r in

5251 so that o nly lum inance signa l Y is allo wed th ro ugh .

5251 a lso causes a de lay o f the lum inance signal o f 500ns.

C onsequently , the lum inance and chro m inance signa l w ill be

availab le a t the sam e tim e at the v ideo co ntro l IC 7280

(TDA3504).

C hrom inanc e p ath The CVBS signa l is supplied to a chro ma bandpass filte r. In the

case o f a unit wh ich is o nly suitable fo r PAL, th is is fo rmed by

co il 5250 and capacito r 2261. Th is filte r is tuned to 4.43 M Hz.

If the un it can receive bo th PAL and SECAM , the filte r is

extended w ith trans is to r 7251, co il 5229 and capacito r 2300.

W h en the P AL,s ig '1a l is reco gn ised, 7251 is blo cked, w hich

resu lts in a bandpass filter wh ich is o nly bu ilt ro und co il 5250

and capacito r 2261. Th is is tuned to 4.43 MHz.

7251 sta rts co nducting w hen the S EC AM signa l is reco gnised .

The filter fo rm ed w ith SECAM has a bell-shaped curve w ith a

m axim um at 4.286 M Hz. Th is is ad justed w ith L5229.

The PAL chro ma signa l is supp lied a t p in 9 o f IC 7260. Th iss igna l is dem odu lated and deco ded to baseband B-Y and R-Y

signa ls wh ich are ava ilab le a t p ins 2 and 1 respective ly o f IC

7260.

PAL chrom a decoder

PAUSECAM

c hroma d ec od er

IC 7250

The chro ma signa l (PAL, SECAM) is supplied at p in 15 o f IC

7250.

The system rece ived is reco gn ised by m eans o f the co lo ur

burst (in the case o f PAL) o r the iden tifica tio n s igna l (in the

case o f SECAM) o n the back po rch o f the cves signal.

T he ide ntifica tio n c ircu it in IC 7250 re co gn ise s th ese s ign als

and se ts pin 27 h igh if a SECAM signa l is received . Using th isth e in pu t filte r is sw itch ed via ·tran sis to r 7251.

S erv ic e T ip : By co nnecting +12V to o ne o f the two fo llo wing po ints (p in 27

fo r SECAM, pin 28 fo r PAL), IC 7250 is se t in the requ ired

system . Th is canbe used to fac ilita te e rro r searching . The

id entifica tio n c ircu it d escrib ed fo r th is is b ypa sse d in th is way.

B aseband d elay line The B-Y and R-Y signa ls co ming fro m the chro ma deco der a re

supp lied to the baseband de lay lines in IC 7221 (TD A4660).

CS 35 699 GB



T he d ire ct s ig na ls d ela ye d o n e lin e tim e a re a dd ed to g eth er.

T he c o rre cte d B -Y and R -Y s ig na ls a re s up plie d to th e v id eo

c o ntro l IC 7280.

T he v id eo c o ntro l ic dematr ixes R-Y,8-Y and Y s ig nal s i nto

R,G a nd B s ig na ls .C o lo u r s atu ra tio n (p in 12), b r igh tness (pin 17) a nd c o n tr as t (p in

16) a re a dju ste d u sin g th is IC . A b eam c urre nt lim ite r is a ls op re se nt. T h e o u tp u t s ig na ls a re RGB s ig na ls (p in s 1,19,20)whic h c o ntro l th e RGB o u tp ut am plifie rs o n th e p ic tu re tu be

board .

Source se lec tion T he v id eo c o ntro l Ie h as 2 in pu t s ou rc es :

a . R,G,B fr om th e d ematrix ed R-Y, B-Y a nd Y s ig na ls .

b . R,G,B a nd fa st b la nk in g s ig na ls from th eeuroconnector .

If th e v olta ge a t p in 7 (fa st b la nkin g) o f th e Ie is lo w , th edematr ixed RGB s ig na ls a re p as se d to th e c o ntro l am plifie rs . Ah ig h v olta ge a t p in 7 s witc he s th e RGB s ig nals . f rom t hee ur o co n n ec to r to th e c o n tro l amp lifie rs .

Sandcastle pu lse The san dcas tle p uls e s yn ch ro n is es c o lo u r, d e co d in g . lum in an cea nd c hrom in an ce s ig na l p ro c es sin g a nd c o rre la te s th e RGB

s ig na ls w ith th e r as te r.

RGB outpu t amp lifie rs The RGB o u tp ut am plifie rs c o ns is t o f 3 id en tic al c la ss Aamp lif ie rs bu ilt r o und t ran s is to r s 7205, 7218 and 7227.

Peak beam curren t

limiter

T he p ea k b eam c urre nt in fo rm atio n (E HT in fo ) is m ea su re d v ia

d iode 6282 in o rd er to p re ve nt o ve rlo ad o f th e p ic tu re tu be a ndth e h ig h v o lta ge s up ply .T his is d o ne b y a dju stin g b ac k th e c on tra st v olta ge o f Ie 7280.C o n se qu en tly , th e c o ntra st v o lta ge is a lw ay s le ss th an 4 v o lts .

H igh vo ltageF oc us VG2

T he h ig h v o lta ge , fo cu s a nd VG2 v olta ge s a re s up plie d b y th e

lin e o utp ut s ta ge . T he fo cu s a nd VG2 can be set by m eans o f

P ic tu re tube flashove rprotection

T he fo llo w in g m ea su re s h av e b ee n ta ke n to p ro te ct th e re ce iv er

aga in s t p ic tu re t ube fl ash over :

1) s pa rk g ap s (SPR3,7,9) o n a ll e le ctro de c on ne ctio ns o n

th e p ic tu re tu be b o ard .

2) r es is to r s in s er ie s w ith RGB electrodes (3203. 3216.3229).

CS 35 700 GB



6. Synchronisationand deflec tion

In add itio n to the in term edia te frequency pa rt (IC 7015/2A), IC

7 015 a lso c onta ins the h orizo nta l an d v ertic al s yn ch ro nis atio n

c ircu it and a sandcas tle pu lse genera to r (F ig . 6.1).

The CVBS p icture s igna l is supp lied to p in 28 o f IC 7015/28.V ia the s yn chro nis atio n s ep ara to r in the IC , the s yn ch ro nis atio n

s ign als a re s up plied to the ho rizo nta l o scilla to r, the v ertic al

o sc illa to r a nd th e id en tific atio n circu it w hich em its a "h igh"

s igna l a t p in 25 w hen the transm itte r is reco gn ised .

Horizontalsynchronisation

T he ho rizo nta l o sc illa to r is a fre e-run ning s aw to o th g ene ra to r.

Its free-runn ing frequency is set us ing 3356. W h ile 3356 is

be ing set, the inp ut (p in 28) sho uld be co nnected to the +12C .

If a trans mitte r is re ce iv ed, th e free -runn ing o sc illa to r is

synch ro nised w ith the synchro nisa tio n p ulses o f the

s yn ch ro nis atio n se pa ra to r. T he s ync hro nis ed s aw to o th vo ltage

is sup plied to the o utpu t am plifie r w hich de live rs a squa re -w ave

vo ltage a t p in 29 , the ho rizo nta l co ntro l s igna l.

Hor izonta l centr ing

. Ver tica lsynchronisation

The ho rizo nta l centring is set us ing po tentio m eter 3354.

The fram e pulse is o bta ined fro m the synchro nisa tio n s igna ls o f

the synchro nisa tio n sepa ra to r and sup plied to a c ircu it w hich

co unts the ho rizo nta l p ulses . A fram e p ulse is genera ted afte r

625 lines . The ve rtica l co ntro l s igna l is p resent a t p in 4 o f the

IC w hich is synchro nised w ith the ho rizo nta l and ve rtica l flyback

pu lses.

Sandcast le U sing the h orizo nta l and v ertic al p ulse s, the sa ndc astle p uls e

gene ra to r genera tes the sandcas tle signa l wh ich is ava ilab le atp in 30 o f the IC .

Horizontaldeflection

The ho rizo nta l co ntro l s igna l co ntro ls the line o utp ut s tage,

trans isto r 7445 and trans fo rm er 5445 v ia transis to r 7440 and

co il 5441. The line o utpu t s tage sup plies the ho rizo nta l

de fle ctio n c urre nt an d v ario us s up ply vo lta ge s.

The ho rizo nta l flyback s igna l is tapped to the seco ndary side

Verticaldeflection

IC 7400 (T D A3653) is used fo r the ve rtica l de flectio n.

Th is IC is co ntro lled o n p ins 1 and 3 w ith the vertica l co ntro l

s igna l o f IC 7015/28 and a deflec tio n vo ltage is gene ra ted at

p in 5. The p ic ture centring is se tw ith the res is to rs 3401 and3408 and the p ic ture am plitude can be set us ing po tentio me te r

3410. The vertica l flyback s igna l is gene ra ted at p in 8 o f the IC .

F or a deta iled descrip tio n o f the ho rizo nta l and vertica l

de fle ctio n, s ee th e d ia gram des crip tio n o f C ha ss is G R1 -A X.

CS 35 702 GB



'4iiil:i41 _

O I , s v o v _ l i I ~ vJ a l m i l w eV _-12V_

2 O i ! " D I V 2Ops/0iV 2Ops/DIV

8 8 ~

o v _U 1 J I , v .IDI'~445

o v_ . r L . A IV2

L.O.T.

o v _2Ops/OIV 2 O , . . / D 1 V 2IlI<s/DIV

~ ~ ~

2465 HOR

~FLYBACK

+'2

A VERT.

o e . ;nI"l YBACK NlJ I 4 0 Vev_

+26V5ms/DlV 5msjOIV

6416 ~ ~

PRS.0689OT10 /106

F ig . 6 .1

CS 35 703GB



_ " ' I ' ' ' : i i '

DEGAUSSING

5590,-------,

~2 ; 2 1

5525

220. "v 1540

E:J1 5 4 0I

9V9

( 2V SI .. +9V

12

,I I.

I,, IL~ _

B

5!ls/OIV

C D . ~

- 9 V _ ~ 1 ' V 2 r r r I 2 V 5SpSjOIV 2V5 - SmsjOlV

,,, ,,

CPRS .0 6 9 17

110/107

- l 1 v _ l r 1 r I ' 3 V _ t 1 1 l v5 J . I s / D1V 3V - 5ms/DIV

~n r I s s o v - I r l r - l - I 4 0 0 VOV_

U U o v _ 1 I - II5iJSj01V5msjOlli

F ig . 7 .1

nw o v _ I M I ~ v-24V - . Smsj01V

5IJ sjOlV

5 1 - 1 s D IV

C D [§]

Sms/DN

CS 35 704



7. Powers u p p l y

-------

The p ow er supp ly is a m ains-iso la ted S OP S (S elf O sc illa ting

P o we r S up ply) (F ig . 7 .1 ).

The o utput vo ltages a re : +95 fo r the line o utput s tage , +9V fo r

the so und o utput am plifie r and +5A fo r the m icro co mpute r if the

un it is in the s tand -by m ode.

The supp ly is pro tec ted aga inst o ve rlo ad , o vervo ltage and

un lo aded o r sho rt-c ircu ited o utpu t. If the TV set is sw itched to

the s tand-by m ode , the SOPS supp lies +5V to the

m icro co mpu te r in the o pera ting system . In the s tand -by m ode

a ll o the r c ircu its rece ive a vo ltage w hich is co ns iderab ly less

than the no mina l va lue so that these c ircu its canno t wo rk.

Degaussing The m ains vo ltage, 220-240V ±10% , is supp lied to a d io de

rectifie r 6602-6605 v ia the m ains sw itch S K1 ' and a sup press io n

filte r 5500. D egauss ing takes p lace w hen the un it is sW i tched

o n because a h igh current m ay pass th ro ugh the PTC 3501

and the degauss ing co il 5590. The res is tance va lue o f the PTCw ill increase qu ickly and the current w ill be lim ited to a

min imum.

S OP S sup ply Genera lly, the po wer supp ly co nsis ts o f 3 b lo cks: a b lo ck ing

o sc illa to r "A " (25 24 -5 52 5-75 25 ), a s witc hin g c irc uit "B " (7 51 2-

7515-7516-7514/2A) a n d a c o n tr o l- -c ir cu it " C It ( 7537-7552 -7554 -

7514/2B) .

The rectified vo ltage is supp lied to SOPS trans fo rm er 5525 and

switc hin g tra ns is to r 7 52 5.

S witch ing transis to r 7525 is sw itched in and o ut o f co nductance

v ia the sw itch ing c ircu it. The circu it is s tarted up by res is to rs3514-3518-3520.

W h ile the trans is to r is co nducting , energy is sto red in

trans fo rm er 5525 and, if the transis to r is b lo cked , th is s to red

ene rgy is re leased to the seco ndary s ide. The requ ired supp ly

v o lta ge s a re a va ila ble a fte r re ctific atio n a nd sm oo th in g.

Us ing in fo rm atio n o n the o utpu t vo ltage , the sw itch ing c ircu it is

co ntro lled by the co ntro l c ircu it v ia o pto co up le r 7514.

Fo r a deta iled descrip tio n o f the SO PS princip le , see the

d iagram descrip tio n o f C hass is G90B. '

Stabilisation The +95 o utpu t vo ltage is m easured by m eans o f a d iffe ren tia l

am plifie r 7 53 7-65 37 w hic h ca n be s et us ing p oten tio m ete r

3535. D epend ing o n the vo ltage m easu red, th is am plifie r w ill

co ntro l the sw itch ing c ircu it v ia the co ntro l c ircu it and the

o pto co up ler so tha t th e s witc hin g tran sisto r s witc he s o ff ea rlie r

(if the o utpu t vo ltage is to o h igh ) o r la te r ( if th e o u tp ut v o lta _g e is

to o lo w). In th is w ay the o utp ut vo ltage is s tab ilised acco rd ing

to th e lin e s up ply c irc uit.

CS 35705 GB



_ i tu i ! i : , € , .Protectivedevices

Stand-by

The po wer supp ly is p ro tec ted aga ins t o vervo ltage o f the +95

o utput vo ltage and the +58 line o utput stage po wer supp ly . V ia

a thresho ld co ns isting o f zener d io des , 6555 fo r the +58 and

6557-6558-6559 fo r the +95, these two vo ltages a re supp lied to

th e thy risto r c irc uit 75 55 -7 55 6. If th e thres ho ld is e xce ede d,

then the c ircu it is ac tiva ted and the SO PS and the re fo re

ind irec tly a lso the line o utp ut stage sup ply a re sw itched o ff.

T he +5V supp ly vo ltage fo r the m icro co mpu te r sho uld be

s tab ilised du ring no rm al TV o pe ra tio n, bu t a lso in the s tand -by

m ode . D uring TV o pe ra tio n the vo ltage is supp lied by the +58

line vo ltag e. T his vo ltag e is sta bilis ed at +5 .1 V b y tra nsis to r

7561. -

If the stand -by co m mand is rece ived at trans isto r 7571, th is

s to ps c on du ctin g. C o ns equ en tly, thy ris to r 6 570 sta rts

co nducting . The vo ltage o ve r co ils 1-5 o f trans fo rm er 5525 is

then rec tified by the thyristo r and th is w i'll be a grea t dea l h ighe r

than +58. V ia trans is to r 7553, th is h igh vo ltage , is supp lied to

co ntro l c ircu it C m inus a th resho ld o f d io de 6568.

T he co ntro l c ircu it no w stab ilises the vo ltage sup plied by theth yris to r a t a pp ro xim ate ly + 1 3V . C o nse que ntly , a ll o utp ut

vo ltages are ad justed so far back that the co nnected c ircu its no

lo nger wo rk. As the vo ltage o ver capac ito r 2560 is no w still

+13V , -the s tab ilisa tio n c ircu it fo r the +5A co ntinues to wo rk and

the supp ly vo ltage o f +5V is a lso p resen t if the TV se t is in the

s ta nd -b y m o d e.

Powe r-On Rese tPOR

In o rde r to ensure tha t the m icro co mpu ter s tarts up co rrec tly a

PO R S igna l (P o wer-O n Rese t) m ust be g iven . The PO R

pro cedure co nsis ts o f keep ing the rese t p in o f the

m icro co mpu te r (33-IC 7600) "lo w" fo r a t least 1 m sec. The

reset p in is kept "lo w" by m eans o f zene r d io des 6562 and6565 and trans is to r 7563. The transis to r o nly s ta rts to co nduct

when the supp ly vo ltage o f +5V exceeds the zene r vo ltages

and the requ ired basic em itte r vo ltage o f transis to r 7563.

Important :

A fte r a co mpo nent has been rep laced , the supp ly vo ltage

sho uld s lo wly be ad justed upwards fro m 0 V us ing an

a dju sta ble iso la tin g tra ns fo rm er. T he +9 5 s ho uld b e m ea sured

a t the sam e tim e.

If a pro tective dev ice is ac tiva ted o r the supp ly do es no t

s ta bilis e, se vera l c om po nen ts are d efe ctiv e. T his m eth od

p re ven ts th e co m po nen t jus t re pla ce d be co m in g de fe ctive

aga in .

Se rv ice tip s

1. The +95 is no t p resen t and fuse 1540 is de fec tive .

P o ss ib le c au se : 7 52 5 is d efe ctiv e.

If 7525 is de fec tive , a lw ays check o pto co up lers 7514,

7512, 7515, 7516, 7554, 6515,_ 6545, 6549 and 2550.

CS 35 706 GB



,' j U W : ' i a _

2. The +95 is OV b ecause the po wer supp ly do es' no t

s ta rt. W h ile the po wer supp ly is being ad justed upw ards

fro m OV, m easure the vo ltage a t the base o f 7525 w ith

a n o s c illo s c o pe .

a . If the O SC illo sco pe do es no t sho w a signal o f appro xi

m ate ly O .5V when the supply vo ltage is increased by

severa l vo lts, the fault is p ro bab ly caused by a sho rtc ircu it o n the prim ary s ide.

b . If the o scillo sco pe sho ws a signa l o f appro xim ate ly

O .5V, the fault is p ro bab ly caused by to o grea t a lo ad

o n tra nsfo rm er 5525,

fo r e xample :

-a fau lt in the co llecto r c ircu it o f 7525

-o ne o f the dio des o n the seco ndary side o f the

tra ns fo r mer is d efe ctiv e.

3. The +95 is sho wn o n the o sc illo sco pe as a d irect

cu rren t o f appro xim ate ly + 1 9V w ith a saw to o th

superim po sed o n it .

T he u nit is p ro te cted . C he ck th e pro te ctive c ircu it.

4 . The +95 is less than 100V, but no t p ro tected.

Rem ove co nnecto r M 5.

T he re a re n ow 2 po ssib ilitie s:

a . the +95 is p resen t

b . the +95 is to o high .

In the case o f s itua tio n a., the supp ly c ircu it is wo rking

co rrectly and the fault m ust be caused by the line

o u tp u t c irc u it .

In the case o f s itua tio n b ., an a ttem pt sho uld firs t be

m ade to ad just the +95 aga in w ith R3535.

If th is do es no t wo rk: .a . C h ec k th e s ta bilis atio n c irc uits 7 53 7,6 53 7,3 55 3,

3551, 3568 and 7552.

b . M easure the vo ltage o ver C2517.

If the re is no vo ltage here, then the fau lt is p ro bab ly

caused by 6522 o r 3522,3521,3517 o r 6517.

5. The +95 is appro ximate ly +35V. The un it is in an

u nd esira ble s ta nd -b y m o d e.

C he ck th e s ta nd -b y c irc uit.

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Chassis Anubis a Ac v1 2