Akai CT 2870 UK, CT 2570 UK Service Manual

MANUAL

1 Stereo module

69113789

RF-IF module )

5829 02 58

CT 2570 UK

Ident-Nr. 5436 03 00

CT 2870 UK

Ident-Nr. 5436 03 10

Replacement parts list

When ordenng spares please quote item and order number. When ordenng (sub-)assembks (modules), gwe the assembly number in addition!

A Safety components in accordance with existing regulations. These components must only be replaced by original component parts

CT 2570 UK CT 2870 UK

Cab,net 61128636 Cablnet 61122861 Front plate 64172606 Front Loudspeaker blind 64110720 Loudspeaker blind 64110721 Operatlnq ““0 lid Holder for operatmq un,t Ikd a681 10 06 Holder for umt I!d operatmq 8681 1006 Grille for mdlcator a251 44 19 Grille for lndwxtor a251 44 19 WIndow for lndlcator qrllle 6466 37 36 Window for lndlcator grille 6466 37 36 Pad 8642 0148 Pad a642 0148 Rear couer Holder for rear cover 8624 47 10 Holder for rear cover 8624 47 10 Screw for pcture tube Picture tube A 59 ECF 00 X 01 SEL A 43622555 Plcture tube A 66 ECF 00 X 01 SEL A 43622803 Earth for plcture tube 6141 0305 Earth for tube Sprlnq devtce for earfh,“q 735128 46 Spnnq dewce for earthmq 7351 28 48

Deqausslnq co11 A 45880524 Holder for picture tube 8623 3140

Hook for deqausstnq coil 868172 15 Deqausmg cal A 4588 05 24

Loudspeaker Holder for loudspeaker 73680196 Loudspeaker an. IOW 431107 15

Chaws conduct, left 8625 11 63 Loudspeaker 4 S!. 10 w 43110921 Chassis co”duct. rlqht 86251164 Holder for loudspeaker 7368 0196 Holder for STEREO-Modul 8625 48 09 Chassis conduct. left 8625 11 66 Plunger pi” for RF module a642 75 05 Chassis conduct, right 8625 1165 Matns pushbutton 631536 la Mains pushbutton 631536 18 Holder for decoder 8625 47 07 Holder for STEREO-Modul 86254809

89.15~

86870281

6214 $068 Rear ccwer. qrey

78640221

43110715

plate

Operattnq U”,t Ild a687 02 a2

Screw for picture tube

pxture

Hook for deqaussmq toll

Plunger PI” for RF module a642 75 05 c 3951396 2.2 UF 100 V 342175 52 Holder for decoder 8625 47 07

64172985

62140959

18640221

6141 0305

86817215

When re-ordering manuals, please quote the model name and part number.

66117924(104)S

Picture and sound IF-adjustment

Required measurmg equipment: sweep generator Wlfh marker

tr=“Smltte, SIgnal generator. Oscillograph: RF rectifier probe B!as voltage ,nstrument

Stage to be

NO.

adjusted

1 1

UHF/IF filter

Test arcu~t 1. Sweep , gen. “,a 15 pF to TP 2 / (UHF tuner) approx I 300 mV TP 203/204 to

30 42 MHz. max. output 200 mV 5 5 MHz. dispersion k 15 kHz, f,,. = 1 kHz Sens~t~v~ry 10 mV/cm 1 V/cm

adjustable from 0 10 V

Connect. oscillor.

Osc~llo. “,a probe to TP 101/102 Ampiltude (VC and SC must have the same helghf) Bandwtdth can be 10 mV/cm See Fig 1

Preparations: !&as voltage instrument to TZ 214 Check U V 12 V i 10% at TZ 23 The cores

must be at the upper end of the co11

Adjustment procedure ~ Oscillograms Remarks

Adjust to max. amplitude and level roof with L 62and L 64 narrowed wth L 63.

UHF/VHF/IF-

filter

2 Reference circuit

Monitoring of IF x

3 1 frequency

response gen. via Interstage transf Osc~llo to T 24

52 DF-AF

Some voltage level from sound

5.3

channel 1 and channel 2

1 Monitoring of

video signal

1 Test c,rcu,t 1 Sweep ’ Osc~llo. “,a probe to

en. “aa 10 nF to TP 6 TP 2031204 Amplitude Adjust to max amplitude and level roof wth L 161 and /

I g

(UHF tuner) approx. approx 20 mVicm L 162 (BT and FT must have the same height)

20 mV TP 4 to earth

Test c,rcu8t 2 Sweep 1

gen "Ia mterstage

transformer (4.1) to

TP 2011202 (approx.

20 mVI

Attenuatnn xc. tq test ClrCult 3. TP 102 to earth wa ’ ( ) 2.2 “F’

/ Test circuit 2 Sweep ~ ~ (4.1) to TP 2031204

(approx. 150 mV1

SIgnal generator

( ~zx;,;k~; osz”‘o to Tz33

Signal generator5.5 MHZ on TP 211 and 5.74 MHz

~ on TP2,2

With the ald of a standard modulated N transmitter. the video output voltage should be 2 V,, + 0.2 V

1 See Fig 2 I

Osc~llo to TZ 24 Tune frequency marker 38.9 MHz to max amplttude with ~ Amplitude 450 mV/cm L206 (UK = 39.5 MHz)

Set frequency marker 36 MHz to 1.7 V,, - 0 d0 with bias voltage at TZ 214 Marker 36.9 MHz should Ile between

- 5 dB and - 7 dB. marker 34.5 MHz between - 3 dB and

Amplitude 0.5 V/cm

Osc~llo to TZ 31 Adjust R 233 on 761 mV,,.

Osc~llc to TZ 31 and Ti! 33

- 5 dB.

’ / Tune L 226 CL2361 to AF max. and ml” dlstortlon factor 1

Tune sound channel 2 wth R 225 (R 233) to have the same

haght wt sound channel 1 (appr 1%).

A “,

Swtch the respectwe term,“& of TZ 3liTZ 33 to earth v&h 10 nF capacitors

389YHI

-“.- ~.,-“m,

Y,5”*2

Abb. 1

Probe for RF tuning

Test circuits 1

Abb. 2 Probe for tuning of the IF coil

Test circuits 3

_. _ _ _ _ MS, PARALLELTON 5T”FE (51 PARALLEL SOUND STAGE

Instructions for dismantling: Turn the two red plunger pins by 90” Remove module from

bracket (Fig. 1).

1. Apply pressure to the plate channel simultaneously with both thumbs, until the cover seaming bends, then remove cover (Fig. 1).

2. Before the cover can be put back on, the plate channel must

first be pressed back into its proper position from the InsIde (Fig. 2).

3. Put cover back on.

Raststift Plunaer p,ns

Ambedue le spme

Gegenstand Item Pike Ricambi

HF-ZF Modul (Kabeltuner) RF-IF module (Cable tuner) Module HF-BF (Tuner rhseau cable)

pour

Modulo MF-BF (Tuner a larga banda)

IC 161 TDA 5030 IC 171

IC 201 TDA 4427 A IC 202 TDA 2546 A

Tl BF 989 T, BF 996>E 6327 T 41 BF 569-L

T 61 BF 569-E 6327 T 162 BF 550

T 163 BC 848 AF D 1 21 22 41 EB 221-S?

U664B

Bestell-Nr.

1 Order no.

N‘ de corn. No. di rif.

5829 02 58

MOS 3775 05 73

MOS 36110711 F 201 J OFW 3203

3761 1725 L 211 3761 1623 L 244 I

3761 1358 F 201 OFW G 3205 361107 13 F 202 Filter ’ F,lter I Fiitre

36120711 361207 13

3612 07 25 36145321 3651 0525

Gegenstand Item Pi&x R’cambi

D 160 161 LL 4148 L 202 Drossel i Choke 1 Bob L 2051245 F~ifer / Filter / Flltre / L 206 L 207 Drossel i Choke I Bob de se” i Bob,na I L 210 DrosselI Choke 1 Bob

L 226 236 1 1 Filter Fflter Flltre i Fllfre 5.5 MHz 4555 30 24

Anschlufllelste 34pollg Female piug 34fold Reglette a doullles. 34fo1s I Sp~noft~era 34~011

G?hausedeckel Cabinet can top B3her parte super~er I Coperchlo schermatura

Antennenbuchse Antenne socket I 41439045 PIIse pour antenne I press per antenna

Filter ! Filter / Flltre i F,ltre 38.9 MHz ~

Spule i Co11 i Bobme i Bob,na Drossel Choke Bob f de sell Bobina / 4557 16 25

’

Bestell-Nr. Order no. N de corn. No. d, rd.

de sell 1 Boblna ~ 4557 16 29

Filtre 38.9 MHZ 45553022

de setl i Boblna ~ 4557 16 25

F~ltre

36560311

45553023 4557 1649

4544 07 46

45558552 4555 85 53 4555 84 15

41451675

i 83164501

I---+

UHF “DRSTUFE

UHF PREAMPLlFiER

RF-IF module

5829 02 58

n-n--.-- -

-- _--. ___

”

+ 9 hidden pages