Tandberg 12 Service Manual
This is the 59 pages manual for Tandberg 12 Service Manual.
Read or download the pdf for free. If you want to contribute, please upload pdfs to audioservicemanuals.wetransfer.com.
Extracted text from Tandberg 12 Service Manual (Ocr-read)
Page 1
Preface This service manual covers the Tandberg tape recor- der models l2-4 and 12-2.fhe model series l2 is a fully transistorised, three speed stereo, record arrd playback unit with two heads. lt is equipped with separate record and playback preamplif iers and sepa- rate power amplifiers for each channel. The power output amplifiers are rated for l0 watts each. The model 12 -2 is the two-track version while the model I 2-4 is the four-track version. The models 12-2 and )2-4 have exaclly the same mechanical system and operating controls. We hope thot everyone concerned with our products will find this service manual useful. April 1967 1 1
Page 2
T'r Contents Technicol specificqlion, Tondberg tope recorder models l2-4 ond l2-2 . The function of the conlrols The inpuf ond outpuf lerminols The mechonism, detoiled descripiion ond odiusiment instruciion The operoling lever . . 4.I.1 The moior switch 1.1.2 lhe eccentric segment 4.1.3 The pressure wheel ossembly 4.1.4 The tope broke 4.1.5 The trip bor 4.2 The turnfoble ossemblies ^ 4.2.1 lhe supply turnfoble ossembly r 4.2.2 lhe lope iight lension . 4.2.3 The toke-up turntoble ossembly A.2.4 Horizontsl ond veriicql olignments of the furntobles 1.3 Clulch olignments 4.3.1 Generol 4.3.2 Fost rewind 4.3.3 Fost wind 4.3.4 Normql forword drive . . 4.3.5 Neutrol 4.3.6 Free 4.4 fhe motor pulley 4.4.1 Threoding of the rubber drive belt 4.5 The speed lronsfer wheel 4.6 The lifting mechonism ..... . '.... '.. 19 5.2.1 The f unclion selecior swilch 5.2.2 lhe speoker selector swilch . 5.2.3 Monourol recording on CHI or CH2 , . 5.2.4 Mixing during monourol recording 5.2.5 Stereo recording 5.2.5 Monourol ploybock, chonnel I or 2 .. '....,. 5.2.7 Stereo ploybock 33 5.2.8 Stereo omplifier 33 5.2.9 Add o irock . 33 S.2,l0Sound on sound 34 5.3 Heod olignment ond frock conlrol with Tondberg test tope 34 5.3.I The Models l2-4 and 12-2 .......... 34 5.3.2 The model l2-2 35 1.0 3t 3l 32 32 33a? 33 32 35 a5 35 35 5.5 5.6 35 36 36 36 36 35 36 2.O 3.0 4.O 1.1 e 9 9't0 l0 12 t2 t2 IJ l3 t4 l5 '15 't5 l6 l6 17 t7 l8 't8 l8 l8 JJ JJAE ) 4.9 The momenlqry stort-stop feoture 4.10 The pressure pqd . . . 4.l l The oulomotic end sfop switch . 4.12 The revolulion counler . 4.13 Assembling the fop cover 5.0 The electronic circuits, detoiled descriplion ond odiusfmenl instruction 5.1.1 lnpuls 5,'I .2 The record pre-omplif ier 5.1.3 The FM multiplex-filter 5.1.4 The equolizing omplifier in record posiiion . '... ' 25 5.1.5 The equolizing omplifier in ploybock position . .. . 26 5.1.6 The equolizing omplifier in omplifier posilion . .. . 27 5.1,7 lhe power oulput omplifier 28 5.1.8 The ploybock pre-omplifier 29 5.1.9 The record level indicotor circuit .. 29 5,l.l0The oscillotor, bios ond erose circuit 29 5.l,ll The power supply 30 5.4 Heod olignment without Tqndberg test topes 5.4.1 Demognetizing 5.4.2 The odlustoble tope guides 5.4.3 The record/ploybock heod 5.4.4 The erose heod Trock conlrol, model l2-4 without Tqndberg test lqPes . - 5.5,1 The record/ploybock heod 5.5.2 The erose heqd Trock conlrol, model l2-2 without Tondberg lesi topes .. 5.6.1 The erose heod 5.6.2 The record/ploybock heod . . Electrical qdiustments for Tondberg tope recorder models 12-4 ond 12-2 . . 5.7.1 Adiustment of ihe Power outPuf omplifier 5.7.2 Adiusfment of the outpui level 5.7.3 The quiescent currenl . 5.7.4 Adiustment of the FM MX-filter 5.7.5 Control of lhe frequency response in omp' position 5.7.6 The boss conlrol 5.7.7 The ireble control 5.7.8 ,Adiusfment of the record currenf ond the eleclronic beqm indicotor circuits . The electronic beqm indicolors The record current. Adivstment of the osc, frequency ond the bios .. Dislortion Bolonce odiustment of lhe pre-omP ouiPuts Adiusiment of the equolizoiion coils Ll ond L2 '. Control of the recording curves . Control of the ploybock curves . Control of the lotol frequency resPonse Power oulpul control . Speed test 36 36 5.7 1.7 1.9 The flywheel with ihe copston 4.7,1 The broke for the flywheel The speed chonge mechonism . . . 20 21 ) O 2l 22 22 22 22 24 24 25 25 36 1A 37 382a Jd 39 39 39 5.7.9 5.7. r 0 5.7 .t I 5.7.12 5.7.13 5.7.1 4 5.7.15 5.7.16 5.7.17 5.7.18 5.7.19 'l ,1 i .t ttT t{tI tt 5.8 Electricol modificotions introduced to the tope recorder model 12 ... .. . .. ' 40 5,9 Modificolions from four-trock to iwo-frock models . . . . . . 41 5.10 Modificofions from 220 volts 50 c/s to ll0 volfs 60 c/s .. 4l 6.0 Ports list .'.....". 4l 6.0.1 Mechonicol ports 4l 6.0.2 Elecrricol ports ' . 46