Circuit Description - Bang & Olufsen Beogram CD 5500 Service Manual

9-1
KREDSLOBSBESKRIVELSE
Indledning
Beogram CD 5500 er en nyudviklet Compact Disc af
spiller, der primzert er teenkt som en del af Beosystem
5500. Beogram CD 5500 kan naturligvis ogsé tilsluttes
og betjenes via Datalink fra andre Bang & Olufsen
produkter eller kan tilsluttes forsteerkere af andre fa-
brikater via phonostik.
Beogram CD 5500 er opbygget omkring iC-settene
beskrevet i kredslobsbeskrivelsen:
Bang & Olufsen Compact Disc
med dekoder IC-set SAA 7210
SAA 7220
TDA 1541P
TDA 5708
TDA 5709
og servo IC-seet
Ovennzvnte kredslobsbeskrivelse omhandler
dekoder- og servo-kredslabet. Denne beskrivelse
omhandler de ovrige kredslab i Beogram CD 5500,
sdsom styring og kontrol, motorkredslab for CD-
skuffe, det analoge filter og digitalt udtag.
Styring/kontrol
Styring af Beogram CD 5500's funktioner foretages af
5IC4 (MAB 8461) og 5I1C6 (MAB 8441). 5IC4
varetager den overordnede styring af CD-enheden,
hvorimod 5IC6 kontrollerer laserenhedens aftastning
af CD-pladen. 5IC6 omtales herefter som servopro-
cessor.
5IC4 (MAB 8461) er en single-chip 8-bit uC med 6 K
ROM/128 RAM bytes og 8-bit LED drive.
51C6 (MAB 8441) er en single-chip 8-bit uC med 4 K
ROM/128 RAM bytes og 8-bit LED drive.
Kommunikationen mellem de,to uCer og display
drive IC'en 1IC1 foregar via IC bus. Servoproces-
soren 5IC6 genererer I°C clock pulserne og optrader
dermed som master pa bussen.
Beogram CD 5500 aktiveres via LINK-forbindelsen fra
Beomaster/Beocenter eller via tryk pa frontpanelet:
PLAY eller EJECT.
Netdelen startes op/afbrydes via 5IC4 ben 22 POWER
ON/OFF.
Se benoversigt over 51C4.
Motorkredsleb for CDskuffe
Den principielle virkemade
Et-nyt-motorstyringsprincip. for.CD-skuffen-i Beogram
CD 5500 har gijort det muligt at mindske CD-skuffens
transporttid vesentligt i forhold til andre kendte CD-
pladespillere.
. A new. motor-control priaciple-for-the CD-tray-in-the
Bang &Olufsen
CIRCUIT DESCRIPTION
Introduction
The Beogram CD 5500 is a newly developed Compact
Dise player which is primarily intended as a consti-
tuent of the Beosystem 5500. Of course, the Beogram
CD 5500 may also be connected to and operated via
Datalink from other Bang & Olufsen products, or it
may be connected to amplifiers of other brands via a
phono plug.
The Beogram CD 5500 has been.designed around the
IC sets described in the circuit description:
Bang & Olufsen Compact Disc
with the decoder IC set SAA 7210
SAA 7220
TDA 1541P
TDA 5708
TDA 5709
and the servo IC set
The above-mentioned deals with the decoder and
servo circuits. This description deals with the other
circuits in the Beogram CD 5500, e.g. control and
monitoring, motor circuit for CD tray, the analog filter
and digital output.
Contrel/monitoring
The functions of the Beogram CD 5500 are controlled
by 5IC4 (MAB 8461) and 5IC6 (MAB 8441). SIC4
handles the general control of the CD unit whereas
51C6 monitors laser unit scanning of the CD. 51C6 will
be termed servo processor below.
5IC4 (MAB 8461) is a single-chip 8-bit uC with 6 K
ROM/128 RAM bytes and 8-bit LED drive.
51C6 (MAB 8441) is a single-chip 8-bit uC with 4 K
ROM/128 RAM bytes and 8-bit LED drive.
Communication between the two uC's and the display
drive IC 1IC1 is effected via th FC bus. The servo
processor 5IC6 generates the 1°C clock pulses and
thus behaves as master on the bus.
The Beogram CD 5500 is actuated via the LINK |
connection from a Beomaster/Beocenter or by
pressing PLAY or EJECT on the front panel.
The power-supply unit is switched on/off via 5IC4 pin
22, POWER ON/OFF.
See also pin survey 5IC4 and 5IC5 in section 7,
Service Tips.
Motor circuit for CD tray
Principle of operation.
Beogram CD 5500 has permitted a significant
reduction in CD tray transport time compared to
other recognized CD players.