AN YOSolidStateStereophonic Tape Recorder4-track,2-channelSystemnoon MR-909SERVICE MANUALSPECIRCATIONSRecording system -** ¢7"* AC magnetic biasing 4-track stereo Frequency response corrttssteste 30-13000 cps (at 7-4 ips)rasing system AC magnetic erasing 70-7000 cps (at 3-% ips)Transistors occececcectttemeen 25B303x2 Ist amplifier Power output Maximum 3 watts (each channel)9SB186x2 2nd amplifier Undistorted 2.5 watts Ceach channel)' tet a BEA AIP sevlebeeiseR eewe ese sae t rot Qa | ; n2581862 3rd amplifier nout and output Microphone jacks 25K onms2581862 4th amplitier25B373 x4 Power amplifier2$B2722 AC biasing oscillatorDiodesand otherelements------18188x2AudioteveldetectorSeleniumrectifierTapespeed------7-14ips(19cm/sec),3-34ips(9.5cm/sec)Playingtime«srrrttttttt 7-44ips120minutes(doubletracks)3-34 ips 240 minutes (double tracks)Fast forward and rewind time Less than 3 minutes (at 7” tape)REMOVING MECHANISMFROMCABINETInordertorepairthemechanismoramplifier,itisnecessarytoremovetherecorderunitfromthecabinet.Toremove,observethefollowing instructions:1)Placetherecorderupsidedownandremovefivephilipsscrewsonthebottomofthecabinet.2)Turntherecordertonormalpositionandremovefourphilipsscrewsatthefourcornersofupperpanel andascrewintheheadhousing.3) Removetwo volumecontrol knobs,twotonecontro!knobsand recording knobbypullingupward.Removeoperatingleverbyturningcounter-clockwise.Aboveprocedureswillpermittheremovalofmechanismandamplifier from the cabinet.ADJUSTMENTOFMECHANISMWheninadequateoperationisnoticedinfastforwardorrewinding,orwhenunusual slackeningoftape occursatthetime ofchanging (switching) fromstopto play,orwhenimpropertensionisnotedonthetapeineach operation, whilethetape recorderisoperating properly otherwise,thefollowingadjustmentsare required.1) Measuring Equipment.Althoughnomeasuring equipmentortoolisrequired, tensiongauge (500gwith20gscale,2kgwith100g scale)willbeusefulafter adjustment.100K ohmsHead phone jack 10K ohmsAuxiliary jacksLine output jacks IK ohmsSpeaker s-teets 4” free edge permanent dynamic,impedance 8 onmsPower source «**:-+::: ++ 90/100/117/220/240V AC, 50/60 cps.Dimensions(WXDXH)-+-MainUnit13”516”x1224”(33X14x32cm)SpeakerBox616”x54"x 1234"(16X1332cem)Weightcsscccrerecesesese creesceeeeeeetenernaeneceeces38lbs.(17kg)2) Brake Mechanism.Foroperationatregularspeed(record-playback)andforchangingfromfastforwardtostop, thebrakeshouldapplystronglytofeedreelbase andweaklytotakeupreel.Turntheadjustingscrewtoadjustcontacttothereelbase.(SeeFig.1).Whenthebrakedoesn't apply,itcausesanopeningofover0.5mm betweenreelbase and brakeshoe.Therefore,thebrakeshoeshould touchthereelbase smoothly.3) Fast Wind Mechanism.Theremustbenoaperturebetweenthetakeupreelbaseandthescrewfor fixingtakeupreelbase.Shouldtherebeanapertureat fastwinding,itisnecessarytochangethenylonwasherforathickerone,or fomovethe leverupwardalittletoupholdthefixingmetalso that thepressurebetweenreelbaseandpulleybecomessatisfactory(SeeFig.2).Checktherotationoffeedreelbase. Aftercompletingthisadjustment,function ‘Rewind’and‘Playback’,andcheckfordefective operation andunusualnoise.Feed Reel Bose Tokeup Ree! Base/ Adjusting ScrewBrake Bound Brake Shoe Fig. 3
