Manual / Guide · c. 1966
Wang LOCI Service Manual
The factory service manual for the Wang LOCI logarithmic calculators: logic, timing, the core store, power supply and maintenance.
Manual / Guide · c. 1966
The factory service manual for the Wang LOCI logarithmic calculators: logic, timing, the core store, power supply and maintenance.
CONTENTS I Introduction 00 ec eee eee beeeeenees 1 Be SCO Bia. sion sons cramcne BEANE ROENOESS ERIS Bin 1 B. LOCI Configurations .........0 0000... ee cece ce eee 1 GC. Possidie Combinations acc eco cisacwmemnemers pee 1 UI GRAIG OSE ONS, concn camcmonsmennwes Teena semen: 2 III. Circuit Card Descriptions ...... 0.0.00. 00 cc cc cece cee ee 7 A. General, Technical, and Physical...................... 7 1401A Card. cc cece ene en eees 9 VAG 2A CAG crssccssaccrcasnoia Merk WEE KOA AEN EE PRA aE DY 11 TAOS A GANG oe i555 Saseie erase space eomsenmund sbew wennecenecenerrstane apewe vie 13 1404A Card... cee eect eeeeees 15 TOGA Cale scx, pyar ees BEE WES HENGE DERERM Sie wosoe, 17 1406A Card... ccc cece eee eeeas 21 WOT A CANS cscs: anccannun ama-caammar ees ER ONAN 23 1408A Card 0. cee ee teen e ues 25 RO Ge EET Ory oerernasacen sia ERR EERIE YoRIEexnouERRIED 27 THITA CAG: sncmacas LEDER BROESE OEE. SENSI es 29 1412A Card 0 eee ene te eenes 31 TSOTAICSIG:. coscanay ues sea WER Ke AU Ee RRERTEROS F 33 DLLHA GAN x scrapes WES SURREY eee ence amecerecemaranmoece qoanen 35 5123A, 5129A Cards ... 0... ieee eee 37 IV. CU-3/CU-4 Circuit Description... 2.20... 0. eee 38 A OUBUE MUM POR sca axcesonanca wen ca BEN GEAR HWE 38 B. Format Logic .......... 0... ccc cee eee e eas 38 CG... FOmat TIMAG sccnoxccwauces san ara Pe BRS 39 D. Teletype Interface... 0... cee ee eee ee 40 EL COge Mat Recs: exomersou Re EENeS RONESR 41 Reader CONC; savas: BEE ERE SSK ERE OONES RS odes 44 Ve HPACKING ANGSHIPDIAG sca son paewrescs SEER MERE 42 Vis (PROGINS cscs ommcmG SAH TS REESE ARE MR COTR RE 43 VIL. GORCIUSIOR ccicy semcewcewes caw cA Wa SEE SEHR vec 45 Appendix Signal Source and Disposition.............. 0... ......000 47 |. INTRODUCTION A. SCOPE This manual is intended for use by those who have had experience in and some expo- sure to electronic computer technology. Specifically, its purpose is to aid repair per- sonnel in LOCI malfunction isolation and/or correction and, in some cases, to provide enough information to enable the service man to correct the problem. The manual contains general and technical description of the componentry, electronic and mechanical, of the LOCI. The information presented, together with discussion of some of the more common malfunctions, is deemed adequate to provide the LOCI user with the necessary knowledge to effect a solution for any problem. Information contained in this manual shall not be construed by the user, however, as authorization to modify the design of the LOCI. B. LOC] CONFIGURATIONS LOCI-—1 - No longer in production; it was the basic unit, having no storage or program- ming capabilities. LOCI-—2 - Now the basic unit; it has storage capability, as well as 80 steps of program capacity (one reader). LOCI-—2a - The basic LOCI—2, with 16 storage registers and 80 steps of program ca- pacity (one reader). LOCI-—2s - The LOCI—2, without program option or storage capacity. LOCI-—282 - The LOCI—2, without program option, but with 2 storage registers. LOCI—2S4 - The LOCI—2, without program option, but with 4 storage registers. C. POSSIBLE COMBINATIONS The following suffix letters indicate possible combinations with the basic LOCI, each suffix representing optional peripheral equipment which can be added to the basic unit. (a) A second card reader option, possible with LOC|—2 or LOCI-—2a. NOTE: The following options are available only with the LOCI—2a. (b) Teletype Model 33 Input/Output Writer. (c) Presin Printer. (d) Teletype and Control Unit 3 (CU-3). LOCI Command Clear Error Clear W-Register Clear Accumulator Square Root Reciprocal of the square root Square Reciprocal of the square Memory Selection Counter I. COMMAND DEFINITIONS LOCI Key CLEAR ERROR CLEAR W CLEAR A v— Viv /7O STEP MSC LOCI Code (01) (02) (03) (04) (05) (06) (07) (10) Definition This command is given to clear or turn off the error indicator light, which be- comes illuminated when the contents of the log register exceeds the limits. The log-register limits are -41.999 999999 to 41.999 999999. This command is given to clear the work, or display, register. When this command is executed, the LOCI will display zeros. It also returns the Memory Selection (MS) Counter to zero. This command is given to clear the con- tents of the A-register only. This command is a mathematical opera- tion which calculates the square root of the W-register and adds that root to the L-register. L+%loge(W) — > L When this command is given, the LOCI takes the contents of the W-register, cal- culates the reciprocal of the square root, and adds the log of the reciprocal of that root to the L-register. L-'rloge(W) ——» L This command takes the contents of the W-register, calculates the square, then adds twice the log of the square in the L-register. L+2loge(W) —-+> L When this command is given, the LOCI takes the contents of the W-register and calculates the reciprocal of the square, then adds the log of that reciprocal to the L-register. L-2loge(W) ——> L This is a command which selects or des- ignates which group of storage registers is active. Each group has four registers and each group assumes an MS value which corresponds to the value of the first register in that group. MS values are 0, 4, 8, and 12. The quantity of stor- age registers is dependent on the type of LOCI used in the operation. LOCI Command Write Multiplication Addition Anti-log Subtraction Decimal Point Division Numbers 0 thru 9 COMMAND DEFINITIONS LOCI Key WRITE ANT! LOG OONDALRWANM=O LOCI Code (11) (12) (13) (14) (15) (16) Definition The WRITE command obtains a printout of what is displayed on the W-register. Print- outs can be obtained from connected Tele- type machines, which can produce both a punched tape and/or a regular paper printout to command the Presin Printer to print. This command multiplies the content of the W-register by the contents of the L-register, At the completion, the product will be in logarithmic form in the L-register. In fact, the x operation adds the log of W to L. L+loge(W) —_ [ss This operation adds the contents of the W- register to the contents of the A-register. At completion, the sum, or total, is in the A- register. A‘W—> A This command takes the anti-log of the con- tents of the log register and displays the answer in the log form. At completion of the command, the L-register is cleared. This command subtracts the contents of the W-register from the contents of the A-regis- ter. This command places a decimal point in the LOCI at the appropriate place. It can be used only once on each display. The decimal point is entered in the W-register only. This command divides the contents of the log register by the contents of the W-register. Each of these commands enters a digit into the W-register in succession, starting with the high-order number, or left-hand side of the display. LOCI Command Run Sign a8 Input MX Output MX Prime Stop Work Register to Program Counter (PC) w— PC w —> XPC Work Register to Decrement Counter (DC) w— DC COMMAND DEFINITIONS LOCI Key RUN CHANGE SIGN PRIME LOCI Code (32) (33) 3) | / (36) (37) (40) (41) (42) Definition This operation is directly dependent on the Mode Selection Switch, which has three po- sitions, STEP, AUTO, and MNL. When the switch is in any one of these positions, there are other dependents which must be consid- ered. The switch advances the program by 1 step in STEP mode, continues the program which might have been stopped intentionally in the AUTO mode, and executes the com- mand manually when indicated by toggle switches in MANL mode. This command changes the sign of the con- tents of the W-register only. It will not affect the contents of the register per se. These are special option commands used with peripheral equipment. This operation clears the W, A, and L regis- ters and the Memory Selection Counter. It puts zeros into the three registers, and gives a zero value to the MSC. This command stops the program. When it is given, the calculating halts, as does any equipment (Teletype, etc.) connected to the LOCI. This command alters the value of the PC. It takes the first two digits regardless of the position of the decimal point in the W-register and places the number into the PC, This com- mand gives freedom of movement within the program. (The PC is a light indicator which indicates the location of the command to be executed on the program.) This command is similar to the W ——> PC with the exception that it changes the sign to negative, the reason being that this will select the second card reader. (It will also light up the X-light on the PC.) This command puts the first two digits of the W-register into the DC if the decimal point is in the second position. If there is only one decimal point position, only one digit enters the DC. The functions of the DC are to control the number of iterations which has been predetermined, or to count the number of times a sequence has been performed. LOCI Command bc —> Ww Work Register to Accumulator Register w— A Accumulator Register to Work Register A —> W Work Register to Log Register Wy fh Log Register to Work Register L—_ w Store PC, DC, then w —> PC Recall PC and DC Decrement (43) (44) (45) (46) (47) (64) (65) (66) COMMAND DEFINITIONS LOCI Code Definition This command is the converse of W—> DC, and takes the contents of the DC and puts it in the W-register. This option does not destroy the contents in the DC. This command enters the contents of the W- register into the A-register. It does not des- troy the contents of W. This command is the converse of W —> A, and it will not destroy the contents of A. This command puts the log of the contents of W into L. It will not destroy the contents of W. However, if the contents of W are 100, the Error Indicator will light, indicating that the limits of L have been exceeded. If W 10.00000, W will be re-aligned to the xx. XXXXXXXXq format. This command puts the contents of L into W, and clears the contents of L after the opera- tion. This command causes the following events: PC ——> PCS (PC Storage) DC —-, DCS (DC Storage) w —> PC Information previously stored in PCS and DCS will be destroyed when this command is executed, and the contents of PC and DC will be put into the PCS and DCS registers. The DC register will remain the same, and the PC register will now have the contents of W. This command exchanges the contents of the PC and PCS, and puts the contents of DCS into the DC. ST PCS PC DCS —+> DC This command reduces the contents of the DC by one. COMMAND DEFINITIONS LOCI Command LOCI Key LOCI Code Definition The following test commands are program tools to maneuver within the program when certain conditions exist: Test Error: (67) If there is no overload of any register, this command advances the PC by four counts. If an overload exists, it advances the PC by one count. There is no effect on the contents of any register. Test DC -0 (70) If DC is zero, this command advances the PC by four counts. If DC is not zero, it advances the PC by one count. There is no effect on the contents of any register. Test A=0 (71) If Ais zero, the command advances the PC by four counts. If A is not zero, it advances the PC by one count. There is no effect on the contents of any register. Test W=0 (72) If W is zero, this command advances PC by four counts. If W is not zero, it advances PC by one count. There is no effect on the con- tents of any register. Test W for-sign (73) If Wis negative, the command advances the PC by four counts. If W is not negative, it advances the PC by one count. There is no effect on the contents of any register. Test L for - exponent (74) If the contents of L are negative, the com- mand advances PC by four counts. If L is not negative, it advances PC by one count. There is no effect on the contents of any register. The following commands are used with some of the optional equipment avail- able, namely, the Teletype: Carriage Return CAR’GE (75) This command can make the Teletype car- RETURN riage return, and also make it skip to a new line if needed. Read READ (76) This command obtains information from the Teletype machine reader, which supplies the LOCI with an input from a paper tape. Read READ (77) This command obtains information from a second tape reader which supplies the LOCI with an input from a paper tape. Ill. CIRCUIT CARD DESCRIPTIONS The LOCI (LOgarithmic Computing Instrument) is an electronic computing machine containing a number of printed cards. Each LOCI contains from 8 to 11 cards, depend- ing upon the machine model. Each card is described herein in detail. A. GENERAL, TECHNICAL, AND PHYSICAL The descriptions on the following pages are accompanied by i!lustrations of the num- bered cards which are to assist the user and the technician to locate specific circuitry. qiidiiae ein aagaingy) aH ! _ a imam Ns Nas ron si rah shi rad Awl ciate tae Na tite! Pyaar th ky iit: WMG ‘ } dad edaidta . * dehiidiliiiiaiins i +) (a) fy : A } 4 { )/4) \} z. LAMAR AAN UTI i itl ] aH: 1401A CARD 1. Decimal Point Position (Neon Bulb) 2. Readout Tubes 3. Transistor Drives for Readout Tubes Note 1: 5. Blanking Circuit Decoder Network Each of the ten clfoults as the same) 6. ER Counter Circuit 7. Input Driver to Blanking Circuit 8. Decoding Circuit for Readout Tubes 9. Control Circuits for Data Traveling between cards . DCN Counter Circuits . Sign Circuits (SN) . Decimal Point Positioning Circuits ee Lh 1401A Card This card contains 11 readout* tubes. The first card is for the sign (plus or minus); the others are for each of the 10 digits in the W-register. There are 10 neon bulbs for positioning the decimal point. The card also contains associated decoding for displaying the sign, 10 digits, and a decimal point of the W- register. In addition, it contains the W-register decimal-point counter and a digital counter for processing the logarithmic operations. The diagram of this card shows the locations of the various circuits. The 11 readout tubes are located across the top of the card, and directly below each readout tube is a series of transistors (either Type 35224 or Type S16393), which are used to drive the tubes. Below the transistor drivers are the germanium diodes which, with the transistors, comprise the decoding circuits of the readout tubes. At the bottom of the card, and centered, isa series of germanium diodes and resistors comprising the contro] circuits for the data traveling between cards. In the lower right-hand corner of this card is the Entry Memory (EM) register counter circuit, which consists of four (4) flip-flop circuits. The ER counter indicates which digit is to be entered. It alsois used to process either number-to-log or log-to-number functions. The ER is a binary coded decimal (BCD) counter, next to which is the transistor circuitry for entry to the card of the input-blanking signal. The decimal-point position drivers and decoding circuits are located in the top left- hand corner of the card. The Work-Register (W) decimal counter (DCN) circuit is lo- cated in the lower left-hand corner. This circuit consists of four (4) flip-flop circuits. *These tubes heretofore had been called NIXIE tubes, but since NIXIE is a trade name of a component no longer used at Wang Laboratories the name has been changed in this manual to ‘‘readout’’ tubes to describe their function more closely. @® @ CG) 0 90 © as, (n) ® 1402A CARD . Number Register Adder Result circuit. . Number Register Result circuit. (ms, s19, nid, cai, ent, sm, Id.) . Control Circuit for the command A-W. . Binary Adder circuits. . Control circuit for one of the Anti-Log Function signals (CC). . Circuitry for the ten digits of the Work Register (NR). 10 7., 8. Control circuits for the following signals: a) Decoder for the log process output b) Memory Select c) Decrement Counter. 9. Shift Pulse Signal Circuit. 10. Adder input control signal. 11. Control to Accumulator Register. Stepping. (ASR) 1402A Card This card contains the 10 digits of the W-register, plus the binary adder used in ad- dition, subtraction, and processing of numbers during log and anti-log operations. It performs the steps for anti-log generation and also the carry-gate process for carry- over of digits. ‘The diagram indicates the location of the various circuits on this card, in the center of which are 80 transistors and the componentry to form the 10-digit W-register storage units. Directly to the left of these units are four transistors which comprise the input for the W-register storage. The four transistors across the top center of the card and all transistors, with the exception of two on the right-hand side, form the Binary Adder circuit. The two tran- sistors in the lower-right center are the DC level control of the 9’s complement cir- cuit, between the W-register and the W-register Adder and its indicator. In the lower right-hand corner are two transistors which are part of a flip-flop network. When this network is OFF, it indicates that the W-register is over.9999999999. The two transistors in the upper left-hand corner and the 11 transistors in the lower left-hand corner form the driver and decoding circuits for the Adder input signal. There are nine transistors which are located on the left-hand center of the card, which form the driver and decoding circuits for the Adder output signal. At the lower left-center are two transistors which form the number W-register shift-pulse circuit. On the right-hand center are six transistors, of which four are used to drive the fol- lowing signals: two drive the CAl, ENT, SM, and LD signals; the other two drive the MS, S19, and NLP 13 signals (refer to signal definitions). 11 badd ‘a 2 | I: egoeco ' 3s =".0 ati sy valli (il o9 Se | ‘egeQ0069 egoQg C909 12 YOe ®@@OMO ®© W = eh Soded EQ ©©OO0O © i) @® 1403A CARD . Circuitry for the storage of the log register 16. Control gate for (#15) (LSN) information (Bin 1, 2, 4, 8) 17. Control gate for (#18) (SN) . Circuit for the log register shift pulse (LR) 18. Memory of the sign of the work register (SN) . Log Register Adder result circuit 19. Main reset of the log register circuit (LRS) . Binary 8 (9’s complement input circuit) 20. Circuit which indicates zero in the log register (LRO) . Binary 2, 4 and 8 Adder output 21. Circuit indicating a number 1 or greater at the end of . Binary 4 (9's complement input circuit) an anti-log operation (MS) . Binary 2 (9's complement input circuit) 22. Circuit controlled by memory select used to shift a1 . Log Register mixer circuit into the Work Register under certain conditions (MSP) aii ake 241 contol cieuts fr "8" signals (,, 85, Sv > Gate circuit for the carrier memory of the log register 26. Control gate for the ertor signal (ERR) a Carrier memory of the log register circuit (C1) 27. Pulse generator circuit (LTP) i oe when error has accumulated 28. Circuit for the error signal (ERR) _ Same as thirteen (LDE) 29. Circuit indicating positive or negative log (ML) ‘ ‘ : 30. Decoder circuit for log and anti-log process (PA) : ativan Sign of the log register 31. Control circuit for the W—L command (LD) 32. Control circuit for the Log Register Adder results and log and anti-log process (PA) 1403A Card This card consists of 12 digits of log information, with a fixed decimal point of two places. It also contains a Binary Adder used to add and subtract log constants gen- erated by the log generator. The card also contains the following miscellaneous circuits: a) The sign of the W-register, b) The error-light circuits, c) The sign of the real numbers in the L-register, and d) Shift pulse, Sy So S46 (refer to signal definitions). The center of the 1403A card contains 96 transistors which, with associated compo- Nabkes aia up 48 flip-flop networks, 12 each for Binary 1, Binary 2, Binary 4, and inary 8. In the upper right-hand corner are the circuits for the L-register shift pulse containing two of the transistors. The other four transistors are for the L-register adder results, one each for Binary 1, 2, 4, and 8. Directly below these six transistors are 14 transistors, in groups of two. Four of these groups, with the associated components, form the Binary 1, 2, 3, and 8 circuitry for the 9's complement inputs. The other three groups are part of the Binary 2, 4, and8 adder-output circuits. Below the adder-output circuits are the components which form the L-register minus circuits. The transistors in the lower right-hand corner are part of the Binary 1 carry circuit. Along the bottom of the card, moving from right to left, the second transistor is apart of the circuit which forms the gate for the carrier memory for the L-register adder. The next two transistors form the circuits for this carrier memory. The next four transistors, of which two form a flip-flop network, are part of the circuit which serves as a blocking signal when an error has accumulated. On the lower right center, there are three transistors which are part of the memory of the number sign of the L-register circuit. To the left of these are three transistors which are part of the memory of the sign of the W-register. Included in this circuitry is a flip-flop network. Continuing to the right, the next two transistors are a part of the main reset of the L- register circuits. The next two are part of the circuit which performs function of giving the DC-level indicating zero in the L-register. The next two are part of the memory-select circuit and the functions it performs. This gives a DC level, indicating that the number is greater than .9999999999 at the end of an anti-log operation. There also is a pulse, controlled by the memory select, which shifts a ‘'1’’ into the W-register at the end of an anti-log operation, if the number is greater than .9999999999. Of the next four transistors, one is for control of a 20-30 microsecond pulse, generated by the turning ON of the L-register transfer. The other three are Sy So and Sy¢ sig- nals, and their functions are as follows: s a) Sq generates a pulse which steps the ER counter during the entrance of numbers. b) So generates a pulse which shifts the W-register during entrance of numbers. c) Sjg generates a pulse which shifts in the number of zeros left in the DCN, if the log was negative at the beginning of an anti-log. The three transistors on the left-hand side, from bottom to top, are the error drivers and a flip-flop network. The next two are used in the circuit that gives the DC level, indicating a positive or a negative log. Directly above these transistors is a group of components forming part of the pulse amplifier (PA) reset decoder circuit which is the master control flip-flop for log and anti-log processing. Above this circuit is the circuitry for control of the W-register to L-register transfer. In the upper left-hand corner is the circuitry for the L-register and the PA control. 13 " aay if } antl 4s: zaR be 2s) th p98 i. t Me 14044 CARD 1. Timing control circuit for the entrance of numbers. 6. Control circuit for a keyboard command and function 2. Timing control circuit for the binary numbers. pulse. 3. Log process (normally zero pulse) circuit. (CP) 7, Circuit for the clock control signal. 4. Circuit for the decoded output of the log process. 8. Control circuit for a function pulse. (NLP’s 0-13) 9. Circuitry for the two main timing pulse. 5. Circuit for the decoding of the 16 step clock. 10. Control circuit for the log process (normally zero (TD's 0-15) pulse) circuit. 11. Control circuit for control of the output of the LR’s 3 complement signal. 14 1404A Card This card contains the 16-step, main timing counter and associated timing pulses which control the entire LOCI. This card also contains the 14-step programmer and the log generator used in all log operations. Along the left-hand side of the card are 16 transistors which comprise the circuitry for the L-register 9's complement. To the right of these complement circuits are two columns of transistors and their associated circuits, which are the decoding circuits for the following signals: ENy, EN2, ENq, and ENg, ali of which originate on the 1405A card. To the right of this circuitry, there are 13 transistors forming part of the log-process step (LPS), which is a pulse to step the log-process control. In the center of the card is a column of 14 transistors and eight more in a cluster at the bottom of the column. These 22 transistors form the circuitry which provides the decoded output of the log process. To the right of this circuit a column of 16 transistors (five to the right of the column) forms the circuitry for decoding the 16-step clock used in each cycle of operation. The next two columns and the three at the lower right-hand edge comprise the main timing-pulse circuits. They cantain six flip-flop networks. The four transistors in the top right-hand corner and the two just below the center on the right-hand edge form part of the circuitry for providing a signal to the keyboard. There are two transistors just above the center of the right hand edge, and these are part of the clock control circuits. 15 12 13. 14. 15. 16. 17. 18. 1a 20. 21. O~©2 LY RR QO ~Acieal | \ | : aT ALT ATT TATE THEE HVALAALTHT NY CEN EEE 1405A CARD . Gate control for the entrance of number. (ENT) 22. Circuit to move decimal point to the left. (FM) . Circuit used to put zero’s into the Work 23, 24. Circuit for entrance of number control of log Register Adder. (NB) Generation and of add and subtract process. (EN1,2) . Control circuit for the clock. (KC) 25. Control circuit for the number Register. (NR) . Control for the back space signal. (BS) 26, 27, 28. Same as #23. (EN2,4,8) . Circuit controlling the summing of the 29. Same as #25. (NR) Work Register and the Accumulator Register. (SM) 30. Shift pulse circuit for the Log, Accumulator and the . Control circuit for aligning the decimal point Number Register. (ACR, C, NR) between the Accumulator Register and the 31. Control circuits for various signals coming from Work Register. (AD) storage. (DCA AND DCN SET GATES) . Pulse generator circuit (input is a DC level) (LND) 32. Control circuit indicating a nine’s complement . Circuitry controlling the transfer of the Log signal between the Work Register and the Adder. Register to the Work Register. (LT) 33. Control circuit for the main reset of the Log Register. . Circuit for memory of the negative log. (LND, ML) 34. Circuit for the Accumulator Register reset. (ARS) . Circuit for the carrier memory for the Work 35. Circuit which moves the decimal point right. Register. (C1) 36. Circuitry for the carrier memory of the Work . Circuit which controls the number to log or the Register. (C1) log to number transfer. (LN) 37. Circuit for the memory of the Ro Gate. (RO) Memory of negative log. (DM) 38. Control circuit for a er shift pulse. (ER) Circuit for controlling Work Register to 39. Control circuit for signals from storage to the Accumulator Register transfer. (LD) decimal counter. (DCN) Control circuit for the log and anti-log 40. Circuit to move decimal point to the right. (FP) process. (NLD) 41. Pulse generator circuit. (not used) cet ne cannes Prmarness _ (RS) 42. Control circuits for S* signals. ($5) ircuit that is set when the first number after wast an operation is entered into the LOCI. (RT) ts ie ee eae wea SELF Control circuits for Log and anti-log process. (DA) 44. Control circuit for memory of the decimal Program reset circuit. point. (DP) Nine's complement of number Register output control circuit. (NR) Control circuit for functions from the Program. Control circuit to blank the decimal light. (DCN) 16 1405A Card This card consists principally of miscellaneous circuits used throughout the entire LOCI. The majority of the circuits comprise shift pulses to control the A-, W-, and L- registers. Because of the complexity of the circuits, the transistors have been numbered and these numbers coincide with the numbers on the diagram. A breakdown of the card circuitry follows: Transistors 1 and 2 — These are part of the circuitry for the main gate-control flip- flop, for entrance of numbers. Transistor 3 — This is part of the circuit which combines diode output of the L- register with output of a flip-flop, indicating number-to-log operation when OFF and log-to-number operation when ON. Transistors 4 and 5 — These are part of the flip-flop network in a memory circuit used to enter the decimal point. Transistors 6, 7, 8, and 9 — These are normally ON pulse generators. Transistors 10 and 11 — These are part of a flip-flop network used to put zeros into the input of the W-register adder during the log operation. Transistors 12 through 15, 19 through 26, 30, 35 through 38, 43, 46, and 50 — These transistors, and the associated components, form controls for some of the signals leaving the card. Transistors 16 and 17 — These are part of the flip-flop network which controls the clock. Transistors 18 and 29 — These are part of the flip-flop network used to control the back-space signal. (This circuit is not used on all LOCI models.) Transistors 31 and 32 — These are part of the flip-flop network used to align the decimal point between the A- and W-registers. Transistors 39, 40, and 41 — These are a part of a control circuit for the blank decimal lights. Transistor 42 — This is part of the circuit which moves the decimal point to the right. Transistors 44 and 45 — These are part of the flip-flop network used to control the transfer of the L-register to the W-register. 7 Transistors 47 and 48 — These are part of the flip-flop network used to control the signal from the W-register adder input, indicating a number of ‘'5,’’ or greater. Transistor 49 — This is a part of a control circuit for the shift pulse to the W-register. Transistor 51 — This is the control gate for the carrier memory of the W-register adder. Transistors 52 and 53 — These are part of the flip-flop network used to control the W-register to L-register transfer. Transistors 54 and 55 — These are part of a flip-flop network used to indicate number- to-log operation when OFF and log-to-number operation when ON. Transistor 56 — This is a control for the memory of the negative log. Transistors 57 and 58 — These are part of a flip-flop network used to control the memory signal of the negative log. Transistors 59 and 60 — These are part of a control circuit for a reset signal gen- erated by Transistors 67 and 68. Transistors 61, 62, and 73 — These are drivers and controls for the master control flip-flop for log and anti-log processing. Transistors 70 and 71 — These are the master control and flip-flop for log and anti-log processing. Transistors 63, 64, and 76 — These are part of a flip-flop and control circuit for the carrier memory for the W-register adder. Transistors 67 and 68 — These are part of a flip-flop network, set when the first number after a previous operation is entered into the LOCI. Transistor 69 — This controls a signal used to reset the programmer. Transistor 78 — This is a control which moves the decimal point to the right. Transistor 79 — This is a control for the pulse used for resetting the W-register. Transistor 81 — This is the reset control for the A-register. Transistors 83 and 84 — These provide direct-current level control of the 9’s com- plement circuit between the W-register and the W-register adder. Transistor 85 — This provides control to blank the decimal lights. Transistor 86 — This is part of the control circuit that moves the decimal point to the left. 18 Transistors 72, 87, and 89 — These are part of the control circuit for the number- register reset and the decimal-counter reset. Transistors 74, 75, 77, 80, 82, 90, 91, 92, 94, and 95 — These act as controls for various signals coming from the storage cards 1407A or 1410A, used to set the Work Register decimal counter. Transistors 96 and 97 — These are used for the control of the entrance of numbers, control of log generation, and control of the adding and subtracting processes. Transistors 93, 98, 99, and 100 — These form the control circuit for the number- register adder input. Transistors 101 through 111 — These form the circuitry (including the flip-flops) of entrance of numbers, control of log generation, and control of the add and sub- tract processes. 19 * e ‘ a, w s 9e ee 6 660 | ia Heratael ‘ i HONG PEEENUEEEE tis M, 1406A CARD 1. Circuit for the Accumulator decimal point 17 and 18. Same as #10. counter. (DCN) 19. A control circuit for the decimal 2. Control circuit for the AW command. (ACD) point. (DCN) 3 and 4. Control circuit for clearing leading 20. Circuitry for the Accumulator Register Reset. (ARS) insignificant digits in the accumulator 21. Same as #10. Register. (ACS) 7 22, Same as #16. 5. Control circuit indicating positive or negative 23. One of the circuits of the sixteen step clock. (TD2) number in the Accumulator Register. (ACN) 6. Circuit for one of the ‘‘S"’ signals. 7. Circuit that contains entry information of the Accumulator Register. 24. Circuit that indicates the DCN is two or greater. (DCS) 25. Same as #20. 26. Accumulator decimal point circuits. (DCA) 8. A Decoding circuit for the “'S’” signals. 27. Work Register decimal point circuits. (DCN) 10 through 15. Circuits for the ‘‘S’’ signals. 28, 29. Same as #16. (S18, 19, 21, 22, 28, 29, 31, 34, 36) 30. Same as #26. (DCA) 16. Driver circuits for the Accumulator Register signal. (ACR) 20 1406A Card This card contains the entire A-register, including 10 digits, a decimal point, anda sign. The card also has a comparator circuit used to align the floating decimal point during addition or subtraction, and it develops most of the control pulses in addition and subtraction processes. The related schematic of the card indicates the location of some of the circuitry on the board. The right side of the card contains 80 transistors which form 40 flip-flop networks, and 6 transistors which are control drivers for the flip-flops, These 86 tran- sistors and associated components form the binary storage circuits. Across the bottom right-hand half of the card are six transistors which form six of the ‘'s’’ signal circuits. To the right of these are some of the decoding circuits for the binary storage. The upper left-hand portion of the card contains five transistors in a row. The first four, together with three down the left center, are part of the decimal-point counter circuit. The fifth is a part of the CAI signal circuit. There is a group of seven transistors, of which three form part of the ACS signal cir- cuit. Two are part of the ACD signal circuit, and two are used with the binary circuits. The next two transistors under the ACD circuit form part of the A-register circuits. Next are four transistors which form part of the ‘'S’’ signal circuits. Near the left-hand edge, in the center of the card, is a group of 14 transistors which form part of the DCA (Decimal Counter for the Accumulator) register circuitry. There are 16 transistors positioned in the lower left-hand corner, five of which form part of the A-register circuit, two each for the DCAg, DCNg, DCS, TD2, and ARS signals, and one for the DCN signal. 21 Dany a , = = ¥ lie ad bo SS vA : PTTTILIZ LLL Gd i} 1407A CARD 1. A complete storage register. 11. Same as #8. 2. Control circuit for the store register. (CA1) 12. Control circuit for the transfer of signals to or 3. Circuit that indicates information is being from the Program counter. (CP) transferred. (CP) 13. Same as #7. 4. Shift pulse circuit for the ACR or N.R. signal. 14. Same as #8. 5. Same as #2. 15. Same as #9. 6. Same as #1. 16. Same as #10. 7. Decimal point inputs (DCA or DCN) circuits. 17. Same as #11. 8. Control circuit for the sign (ACN or SN). 18. Same as #12. 9. Control circuit for one of the decoded sixteen 19. Same as #5. Step clock signals. (TD3) 20. Same as #2. 10. Circuit indicating information is leaving the 21. Same as #3. Decrement counter when it is on. (CA) 22. Same as #4. 22 1407A Card This card is used principally for storage. It has two complete transistor storage reg- isters, each containing 10 digits, decimal point, and sign. The card also has four control circuits used by the programming features in the card. The card is divided into two sections, with the circuitry identical in each section. The three flip-flop networks on each side are the only circuits not used for storage. The three transistors located in the upper left-hand comer are part of the circuitry which provides a shift pulse for the A-register, or the number register. The two di- rectly below these are part of a flip-flop network which is in the circuit that controls the information being transferred into, or out of, the program counter. Continuing down the left-hand side, the next three are part of a flip-flop network and a driver in the circuitry which indicates that information is coming into the decrement counter, the program counter, or into storage. The two transistors in the lower left-hand corner are part of a control circuit for the sign. There are six flip-flop networks across the bottom of the card; the first in the circuitry indicating that information is going out of the decrement counter, or storage, when it is ON, and the next is part of the circuitry which indicates positive or nega- tive numbers in the A-register. Under this flip-flop, there is one control transistor for the decoding of the 16-step clock used in each cycle of operation. The next four flip-flop networks are all part of the control of signals from storage to set the A-register, or the W-register. There are 80 transistors making up 40 flip-flops for PC, PCS, DC, and DCS. The circuitry on the right is the same except that the sixth and seventh transistors from the top and right-hand edge are part of a flip-flop which controls the signal for the store operation. 23 SwWhHe an wm ownan Co \ ATT Tt Tht Ys T uy 1408A CARD . Spare. . Program counter stepping circuit. (PCS) . Gate control of the number Register. (DCNS) . Stepping control circuit for the Program counter. (PCS) . Decoding circuit for the Program counter. . Circuit indicating Data is being received by the Decrement counter, Program counter or storage. . Part of #2. . Circuit that indicates DCN is greater than #2. (DCS) . Decrement counter circuits. {DC) . Contro! circuits for signals from the Keyboard. (LDET) (CRT) (NRT) (ACRT) (DCT) . Control circuit for the Decrement Counter. (DC) 12, 13. Function set and reset. Control circuit for Program code stepping if one of the six decision making tests is true. (PCP) 24 14. 15. 16. 17: 18. 19. 20. 21. 22. 23. 24. 25. 26. Pulse Generator circuit. (AFP) Pulse Generator circuit. (triggered by the run Key) (RE) Control signal circuit for the Program Counter. One of the Decoding circuits for the sixteen step clock. Stepping pulse of the Program counter. Number Register shift pulse circuit. (NRSHIFT) Circuit which indicates when information is being Parallel! shifted into or out of the Decrement counter. (CDC) Control circuits for various signals coming from the Keyboard. Circuit controlling the restore operation. (RST) Spare. Part of the Program counter stepping circuit. (PCS) Circuitry of the Program counter. Circuit controlling the stepping of the P.C. counter. (DCF) 1408A Card This card is principally concerned with the 160-step program counter, the 100-step decrement counter, and their associated storages. The card also contains the decision- making circuits for looping and jumping. From the upper left-hand corner and coming down the side of the card,