Radio Shack 26-3501, Service Manual

Page 1: ...TRS 80 Pocket Computer and Cassette Interface Catalog Number fJJJOJ ...

Page 2: ...ERVICING 4 5 CASSETTE TAPE INTERFACE 14 6 CASSETTE OPERATION I5 7 CHFCK PROGRAM 22 8 CIRCUIT DIAGRAM PARTS 4 SIGNALS POSITION 28 Operation circuit diagram 23 Operation P C B 24 Key i i I Key P C B 26 3503 uicoil iiagi un 27 26 3503 P C B g 9 PARTS LISr FOR 26 3501 28 10 PARTS USr FOR 76 1501 gg ...

Page 3: ...tages l uncliona buffer 16 stages but 15 napes fur parenthesis Subroutine buffer 4 stages FOR NLXT statement buffer 4 stages 1 iogram memory Data memory W pw program Inpui buffer Data buffer mi iiinnot y Arithmetic functions Acd Subtract Multiply Divide Power raising A Tngonometric functions Inverse trigonometric fur ctlonr Logarithmic fuactom hxponenial tunciom Ar uiar transformations S quotO r t...

Page 4: ...on Program memory dau mcmaiy re er e program memory Peripheral unit Audio OMMtte unit recording Tending if rfi prrgram Trmory dali mentnry and MMf t program memory Optional 26 3503 audio cauei ic interface PhyMcal iimenaora 17S W x 70 D x 44 11 mm 6 8 W x 2 7 D x 1 7 H inches Weight Afprox I70g 0 37 lbs 26 3501 Aceiox 240b 0 5J lbO with batUri _ 2G 3S03 For torapttfr frttili of optratna ttw TRS 80...

Page 5: ...s z iit a o 5 2bs b j 6 y nz ct h ih h h i S 12 T il VII 1 k H CV IV KtHI iniU r i 3 _ B ae S5 I ...

Page 6: ...ontrol of arithmetic sequence memorieingof arithmetical Jots and its i I or interpret the cyntnx of the BASIC instruction for deciding what is to be executed or determine and prepare the information lo be displayed but CPU I doei not perfiwm any execution By itself Il only arranges ihedata and inlorma tlon in proper sequence and acts to provide instruction codelo the fPL II via the buffer On Uteot...

Page 7: ...putet ai described below Mapol4K bf RAM 103OD ie Rtnnn orostor Prog am tipihlpmowflfv 001 IMfi 1 7 Fined mmonei Y i b oume HiKli 04 Aithojgrt RAM aiea is mainly shar d by ihe prog air daia and reserve program FOR KEXT q k isgg memories i is also usee I m the subroutine sack FOR NhXT staiemert slack and fixed memories W X Y Z ...

Page 8: ...fiorr the display chip 2 and 31 is used asa fixed memories A V 22 memories 1 r iemcy I IfefllH Itanster buffer o liyies I memory equivalent i or f spl ty Chip 1 is used as a transfer buffer for transactions of instruction let ween CPU I and CPU B Input buffer Rem lining HO Syt s 1 1 me iioi ipt e yiivilent nf Display Chip I kuserl I m the inroil buffet as follow I Any information tnlered through t...

Page 9: ...t 113 VI 111 X O I 1 x I I 0 I II HiidPiV bat in n i rm loijniog i SI nnnin ss DOilD Din n M BDD1D Sll S DDDID SI7 H7Qaa D sis SI S2 S3 S4 S5 S33 T IHOI 11104 1 102 MO 1H02 A5 A5 0 The numeral 4 to be displayed by CPU II is cotiTcrtcd into He lele am character code and earned hrouah on the address data bus hirst the segnwni Si isvkned with the address A8 AI OOOOOOCO to store iheday DNM DIOI 1000 i...

Page 10: ...ounted and decoded to perToim iynchiorUzation wliJi UK common Mgndl Hl HV geneiaicdliom CPU D DSIP Wiih high level wf lhi itgnal pioc siinft of display operation ii indicated RAM data designated by HI 118 is m out on Sl S40 The dam MOtcd in the displa buffet beamed through Si S40 illustrated ibuve tobc fed to the LCD lb indicate 4 un thf i pl y IW and lit rr cnpgfH tor Si lllitivl W for S etc tlm ...

Page 11: ... foi lemptvawre variaiion C Ref ren voltage VDlSPit aiviicc by resistor combinations to provide VA VM and VB VIlKPr I n u vnliag fcw Rmnmnn tignaUtH 117 fiv I I D VA llim vuli age for segment signals SI S40t VM Inlerrrediilevollage fur common and gment signals VB Law voltage lor segment signals NOTE VA VM and VBbejune pulses with jii amplitude of several TOllS due to the influence nf the LSI Adjus...

Page 12: ...ta Read Wiitc signal During disptoy High Pickings key causes it to morr nlari y 5 1 low 13 14 15 16 DIOl DI02 DI03 DI03 In Oul In Out In Out In Out l ila HtR I for address detignation of the input buffer am Ditnlav Phio 1 1 irmsfer buffer m RAM and During dismay High During read in Low _ _ _V_i_ _ _ 17 18 19 20 2 22 23 24 D7a B6a B3a Ma B3a B2a Bla Out Out Out Oui Oui Oul Out Oui Addtess Bus for a...

Page 13: ... CPUII Pin No Siinal Ini Out Description 1 P4 Out Bu i signal C25rni f _ Whert tha buzicr it off Low 1 I 1 Tier ih bWBW iv on High 1 I J 2 4 F3 F2 Fl Oul Out Out Chip fcnible signal 1 Display chip 3 select sienall ChipEmble signal Display chip 2 select signal I Chip Enable signal Display chip 1 aelecl signal During display Low ___ _ Duung tend in Tmm tikiniciilai ily h gh 5 6 7 Vc c V r Out In In ...

Page 14: ... MSP Oui Display command signal Dining display High During execution Low 27 IB 29 VM VA GND In In In LCD display vnhagff Intermediate voltage of the segmeni lignal LCD display voltage High voltage of the segment signal Supply voltage OVl 30 1 32 33 34 35 36 144 H Hi Ht H2 115 HI Out Oui Oui Out Out Out OU LCD common signals backplate 3 38 Vmsp Vb In In LCD display voltage I Low vrltage of ihe comm...

Page 15: ...to SI 2 CPU 11 57 H3 in Primer Busy signal LuW A litll lIlC i lilllCI i IIVH opcuttil 58 Ki4 In Puntei connection identifying iignal Low when ihe pimtei is not connected 59 60 hi 5 Ki6 In In asset to recall signal OM key input signal IC Pin out ic toiiuBr HJu t i npui p tsmvo NASI iwlr in ip 1 lltS mvn id 14 13 18 II ID J K nnnnnnn lay k J fPl r 1 uul1iljul ju I A CM 14 H I tl io nnnnnnn c UUUUlJU...

Page 16: ...eplacing the LSI 2 Be sure to first remove the key primed board fiotn the uppei cabinet If the LSI on the key primed boird is to be removed if the LSI s removed while the key ptlnted board Is on the upper cibinci there is a poistbUity of deforming the key rubber with Ute heal of the wittering pencil Bcsurc tocut each pinof the defeciive K a Measuring current consumption tVwer source volnge 4 72V C...

Page 17: ... steps during which time the next SO steps of data to be Input is peered in ll c input buffet 5 All Is sre recorded for a period of about 6 wCondf in order lo avoid non record able area located at the beginning of the tap lit alto ii uwd for cuing of the recording head 6 Program or reserve program nam is frwlfcaied 7 File name R Data memory is mriicaied with r iK rorle 9 Area for one data memory K...

Page 18: ...When a recording ligral 0 is in be recorded SIS is set high and K4 output is inhibited during that peiiod U which time the reverse sinnal of HA clock pulse 2kHz is carried on lite recording signal This signilh supplied to the MIC jack of he tape recorder via the modulation circuit oJ the Cassette Interface Reproduction Output signal from the EAR jack of the tape recorder is amplified and shaped m ...

Page 19: ...itepenrifM rtn thp limp ointtaiH OfCR a the tailing edge of the mput ctgnil and ti outputs a pulw which u dependent on the tine constant of CR at the ruing edge of ihe input signal The relay operates ON and OH accut ding to the curie nt flow 10 ihe coil and b auivatfil when A b active and deactivated when B KtCUW Startup ol tt r s u Tmmtool ion ul ihc c cirt jj rdin i QA Activa ian of the relay i ...

Page 20: ...HFTI X X RESERVE 8 L SHFTi AT SHFT A 204 X 1 3 TAT A 204 _ RESERVE 9 int k X INPUT AT A 204 RESERVE 10 Sill 1 1 SK RESERVE I AI204 A 204 RESERVE 12 bNItK A 204 13 MODFJ 14 MODEl KlIN 15 SHFTl ISPi 100 A 041 lflO_ RUM 16 ENTER I KlIN 1U0 2 Checking the Cassette Interface Amuires ihat iiep I hut already been executed No Read in Di iploy Remarks 1 OFF Connect tiicCwseUc Interface to the lape recorder...

Page 21: ...ons occur 1 lfcassettestm torunatStep6 2 If cassette fails to run or no jouml is heard at Step 8 3 If cassette does not stop at SicpO 4 If no sound s heard at Step 1 3 U Repeal the procedure it ihc following occur 1 When 5 displayed at Step 13 repeat operation fnim Step 10 If ihe saine indication is Mill on the display repeat Ihe procedure frum Step 5 after emetine A 204 100 If ihc tame indkatixn ...

Page 22: ...O o o Make sure liul 111 upe docs not run 4 CS TA RUN o o CSjSHKTlf A s RUN o o o o o THa lap ttirtc tnnin jnJ u cording tound will be heard I fcNItP 1 h RUN o o o o Hie Miutiil will cext it and tlie upe will stop wlteu is displayed 7 RUN o o RewjiJ lupe to tic begin ning ihc ICUHUDK K KL N o o o o 9 CLO SHFTlTA Cl O fA RUN o o o iU 1 trVI K RUN o o o o ine display ccnietiis will disappear apt wil...

Page 23: ...rdinR circuit of the Interface No Read in Display Ketnaiks 1 s RUN RUN_ RUN Dim No tap recorder motion z i IbtSIcK l 1 KU I RUN kbcokdor soufiu is auuimc Reco dinff sound ceases and 10 is displayed foi about 1 second i RUN 5and 12 pins ot TCXSJHBP lor t ii watert 1 1111 1 _ 1 In J A In A J ln X _ __ l diiuiptia h p f incDiaim ord ig ina ipjjy reco ding Indnplav recording indHDlav Stcrmnalol Ihe in...

Page 24: ...P 2 T z r L l i u 1 SMK1 S ISHET1 IKNTHRI 2 3 z n e T E r k 1 1 1 p i 1 1 I N 1 1 s T 8 2 8 B E E P 8 entek MODfc 1 T 10 G R A dIeNTErI 11 Shi i Isi tl u 1 4 1 fcNlfc fcl ii i 4 7 12 18 1 iMOIH i SHFT 7 S 14 NOUH SHFTliSPCl ii I 4 7 1 i 1 1CLI RAD ENTER J5 i i IS r 1 f r 1 i k i 1 V K I L_ I lENTER S 18 Enter ie OFF 20 1 1 i i si 1 1 32 23 24 26 en i 7 2fi 29 30 1 I i as S3 34 8fi 1 1 1 1 1 36 87 ...

Page 25: ...SVMBOI laavtt i is z3 U SHFT Dill RAD GfAH DEF JrUK TRO WbQU play rec stw RBCn j J J f t 1 i E 1 f O t G O Ul o O Co o _ o o J i o o _ O o o O G 1 1 o i vj o O o I 1 32 ...

Page 26: ...RAM PARTS i I J C HE Hie i Fi Of or I liirl BUSV l v Or lvt n EK M min I cm ai4liM Ki i i 1 1 ss 11 mil SIB B ll ir Pivwl I HH til HHt S cpu D II ft ii Ufa w I TTTT t i fir FKL i i o ZI o 0 0 fl r vB v gyggyij V V V V V ii n i ii 23 ...

Page 27: ...S SIGNALS POSITION Via f Mi IDI f 11 LIS I ...

Page 28: ... 1 SM 1 KH K OMF i U L iwoo n 0 ilOOWir B fSOKQ herniate j _ jr 9NB5 H r 6 ttW M6 nw toam t FnH 9 bfii IP Hi HZ H AS AI m W W ilAi ri M BH IM M ni M mi it TOP VIE tfr WB To KEY to J J 1 ID 5i Ml fim m Vm era 1 BM PW PC lit NO M M A6 M Hb HJ AI W BOTTCM VIE 24 ...

Page 29: ...Key Circuit sunn i M l ftl ill i 23 ...

Page 30: ... 6 O O I iftinmiu fl 8 H D 3 In I 3 a 9 C J BB 8 1 a flOM 23D 1 g n 3 Q 3 3 1 3 3 a i 3 S 2 DO cccp 00 00 D sua iPP I s liB s Q a t ioa a c ...

Page 31: ...C B Ml W M M 4u IB W S S J B S l4 n J V U to Z B l S3 Q D D H EQQQEJE1F1QE1Q QEQQD E Q Q Q Q t ry fR U l B D E nit B H D a ft op 3 S w MH 1 loci i Dicrui sit rn nio i E B i i I D gFLAY 3 1 1 SEIOOt MP m P 26 ...

Page 32: ...Interface Circuit Diagram KtUJM ul _ IPl l U 1H10 can O Interface P C B 27 ...

Page 33: ...85 PGUM51190CCZZ VVLLF8017JE 1 17 8 19 LCD AL1180 Tape for LCD AHB9953 PTPEH1033CCZZ Frame tor LCD ART2986 LANGK1290CCZZ 20 Filter lor LCD AQO430 PPILWI230CCZZ Display niask ART 2987 HDECA1527CCZZ 22 23 Display f tL r ART 2991 PFiLwi acr 77 Key rubber h ms PGUMM1264CCZZ Mcnnct oooccsz 2d Ground sonno ana 6623 25 26 Key lop 08 key Left n lvesl AK 4274 JKNBZ1515CC04 Key top 1 7 key Right lidlvo AK 4...

Page 34: ...ode DS1688L1 AOX 1405 VHDOS158BL11 Trie miner iisok AT 1218 VHH154KD 5 1 LSI Display thiol TC 312S AXX3032 V1liSC431 25 1 LSI CPU 1 SC43177 AX 3033 VHISC43I 77 1 LSI tCPU 71 Sr 4 tl7n AXX 3034 VHJSC431 78 1 IC TC401 1UBP AMX 4439 VHiTC4Q11UBPl IC TC4019P flMX 4440 VHiTC40 9P 1 IC TC4066P AMX 4441 AMX 4442 VHi 1 C4056P 1 IC TC4069P VHiTC4069PM LSI Ram AX 3C3 VHiTC5514PM Sdidresatoi 1 8W I 6M9I1P1 6...

Page 35: ... ADX1405 VHDDS1588L1 1 Thc mistct I160K AT 1218 VHHISaRD SM LSI Display OltW TC43I2S AXX 3032 VHiSC 3125 1 LSI tCPU 1 SC43177 1 1 J nni 1 11 PTAMTO AXX 3033 VHJSC43177 1 Lol lul U l jO JI O IC TC401 1UB AXX 3034 AMX 4439 VHtSC43 1 8 1 VH TC4011UBP1 IC 1 040191 AMX 444Q VHiTC401 9P 1 IC TC4066P l AMX 4441 VHJ7C4066P 1 IC TC4069P AMX 4442 VHiTC40S9P l LSI Ram AX X 3035 VMJTC5514P 1 Sdirl resitTor I ...

Page 36: ... 80 2O ACC104ZCTP RC 7inOBCCZZ Crvti4l 256 kH AMX 2780 RC SPI0 4CC7Z Capacitor Tantalum lOOpF 50V ilOW ACClOIKJCP VCKYPU1HB10IK Capacitor Tantalum lOOOOpF 25V 20 ACC103MFTM VCTYPU1EX103M Capacitor Tintiiuml 1 tF 10V 8Q 2Q ACC105ZCTP RC SZ1Q07CCZZ Carbon resistor 1 8W 220K 5 AN0396EBB VRD ST2BV224J Capacitor Cframicl lOOOpF 50V il Wt ACC102KJCP VCKYPU1HB102K 30 ...

Page 37: ...EXPLODED V I EWC 26 3501 r 31 ...

Page 38: ... A25G39 GCABB2300CCZZ Capacitor Electrolytic 10 P iGv ao7 2o ACC106ZDAP VCEAAUICW 106G Capacitor Mylar O C047 mF 50V 110 ACC4 2KJMP VCQYKU1HM472K Capacitor MylaO 0 047iiF 50V 10 ACC473KJMP VCQYKU1HM473K Capacitor Tantill 0 01 F 25V 20 ACC103MFTP VCTYPU1EX103M Capacitor Tinuil O lMF 12V J20 ACC104MD1P VCTYPUINXICMM D ode D 1588L1 ADX 1405 VHDDS1589L1 1 Relay AB 8127 VH N R57 11 I IC TC4069P AM X 4 ...

Page 39: ...ocation Manjfaclurei Part Number Carton resistor 1 VI 550K 5 ANCM29EB9 VRD ST2BY564J Carton resistor l 4W 33 oftm 5 AN0Q87EEB VRD ST2EY330J Transiitor 2SA733 AA2SA733 VS2SA733 M T arwiitor 7SC453KS AA2SC458KS VS2SC458KSM 33 ...

Page 40: ...EXPLODED V I EWr 26 3503 34 ...