Tandberg-RC20-rem-sm 维修电路原理图.pdf

TANDBERGRemote Control RC 20Service Manuals-:-tleJBatrooIttlffi*omRemote Controlr ransmitterRadioFans.CN 收音机爱 好者资料库Remote Control Unit RC 20The RC 20 remote control svstem uses acordless, infra-red unit to control the latestTandberg tape and cassette decks.The system consists of a battery-driventransmitter, and a receiver which is con-nected to and gets its supply voltage fromthe tape/cassette deck.The RC 20 transmits information with theaid of infra-red light (IR light) which isinvisible to the human eve.The transmitter unit RC 207Battery lifeThe current consumption for the transmitterduring use is 12 mA approximately. Thebattery has a capacity of about 200 mAhours. So the battery will transmit con-tinuously for about 17 hours.Mechanical dismantlingThe transmitter is held together by twoscrews. One of these screws is located underthe battery.E lectrical description- The electronics in the transmitter consistsof two circuit boards. one board for thepush buttons (A1-1) and one board forthe IR unit (A1-2).- The heart of the transmitter is a MOSdevice SAB 3210 (U1).- When the push buttons are operated, thetransmitter is activated and current isapplied to U1.- The oscillator frequency is about 4Z kHzand it is given by Ll, C2 and C3.- The IR output, pin 8, is now active andthe command signals are applied to thebase of Q2.- Transistor Q2 is a buffer the output IR,pin 8, and the current generator consistingof CR4, Q3, R8, and R9.- The purpose of the current generator is toregulate the current through the infra-redlight-emitting diodes to about 1.3 A irreach pulse.NOTE ! The transmitter must not be i MO)on pin 18, U1. The circuit should oscillateat about 43 kHz when the buttons arepressed. If it does not oscillate, see pointJ.3. Check that pin 6, Ul goes low when thebuttons are operated. If pin 6 goes low,see point 4.4. Use an oscilloscope to check that pin 8,Ul has a bit sequence as shown in thetable. If not, check the supply leads fromthe operation buttons and if necessarychange U1.5. Use an oscilloscope to measure the voltageacross R8 and R9. The voltage amplitudeof the pulses should be between 0.55 Vand 0.75 V. If not. check the diodes andQ3.Receiver RC 20R1. The receiver is supplied with an unregu-lated voltage of about 14 V d.c. Check atC6 that Ql regulates the voltage to about10.5 V d.c.2. Check the receiver pre-amplifier with anoscilloscope probe on the collector of Q7.The pulse sequence should be in oppositephase to the pulse sequence shown intable 1.3. Check Ul with a probe on outputs A, B,C, and D. See table 1.Button operated onthe transmitterOutput activated inthe receiverPLAYSTOPWINDREWINDRECORD* (both)WIND and REWINDSTOP and WINDSTOP and REWINDSTOP and PLAYPLAYSTOPWIN DREWINDRECORD and PLAYWIND and REWINDSTOP and PLAY*STOP and PLAY*STOP and PLAY*It;ItG rF=o6BC s19Cnct,IF22lacl-ofTIRECEIVERPRE. AMPA2-1L-I-CLK 2UIIRSAB3209II820pc2820pRECEIVERDECODE RA2-2U4UI,tcJ(oT(Jl-vcc?-r-lcTERECEIVERolBC 1858T:.oloIINTERGRATED CIRCUITS USEDU 1 -SAB 3209 . IR RECEIVERU2 -MC.I/.001 B, OUAD2-INPUI NORGAIE(cMos)U3.5 -MC110118, OUADz-II.PUI iANBATE(cMos)U6 -HINIL332, HEXINVERTERGA,TE,OCswtt-rlFzlf-tllll-IIl rr*IIII uro_ _ _ _ _ _ - - - - - - - - - -cRltD 271cR2LO271cR3LO271so cLcKl CLCKosbScz1 32ro22 IRAz3zt,z5z6zlz8ETA UOOIlLcl1000pTRANSMITTERI R A1-2ERUT NORGATEIlT MNOOATETERGATE,Fs.;oavooo- - -o1BC 517- -TRANSMITTERTransmitter, Keyboardseen from solder side.Transmitter, IR-boardseen from solder side._-EE-q-t-; t.ll_: looooool lREwrr;a 1 t-.!i L*.r+trl .1 1 .lli?,1 - ill:lt.:ijlit-Jf1tEJ 1- Ut *1EF- F1 li.f rrs I ,Al*l dl? d6s-,6JTReceiuer, Pre. amp. board,seen from solder side.R e c eia er, D e c o der b o ardseen from solder side.,-lI)I)ll)l$lor, I_llHlll-lII_J- - - - -s 1 ,Fr*i.YJ:tr q-&-HIEt-lIaffiw*sj1704 - 8 - 79 Part No. 714126Printed in Norway by Reclamo A/STANDBERG INDUSTRIER A/SELECTRONIC DIVISIONP.O. Box 55, BogerudN-OSLO6-Norwaytoardide.*rl;Nootr)