Manual / Guide · 1965
Friden EC-132 Temporary Service Manual (August 1965)
The interim service manual for the EC-132.
Manual / Guide · 1965
The interim service manual for the EC-132.
178269345! 21e 0079! 35081 1.31 00002! 8631449 00000041 551.36 ELECTRONIC CALCULATORS SERVICE MANUAL i if iden, te SAN LEANDRO - CALIFORNIA A SUBSIDIARY OF THE SINGER COMPANY Courtesy The Old Calculator Museum http://oldcalculatormuseum.com ELECTRONIC CALCULATOR 132 TEMPORARY SERVICE MANUAL TABLE OF CONTENTS FOREWORD Page SECTION 1 - GENERAL DESCRIPTION SIMILARITIES TO THE EC-130 1-1 DIFFERENCES FROM THE EC-130 1-1 SQUARE ROOT KEY 1-1 CLEAR DISPLAY KEY 1-1 DECIMAL POINT SWITCH 1-1 DECIMAL POINT POSITION 1-1 REGISTER 4 DATA RETENTION 1-2 ENTRY COUNTER 1-2 PILOT LIGHT 1-2 SECTION 2- ANALYSIS OF OPERATION SQUARE ROOT MATHEMATICS 2-1 SQUARE ROOT FLOW CHART 2-11 PHASE COUNTER 2-17 DECIMAL POINT COUNTER LOGIC 2-23 REGISTER EXPANSION 2-27 DECIMAL POSITION LOGIC 2-29 CLEAR DISPLAY LOGIC 2-30 REGISTER 4 RETENTION 2-31 ENTRY COUNTER LOGIC 2-33 PILOT LIGHT CIRCUIT 2-36 SECTION 3 - ADJUSTMENTS NO ADJUSTMENTS FURNISHED Courtesy The Old Calculator Museum http://oldcalculatormuseum.com ELECTRONIC CALCULATOR 132 TEMPORARY SERVICE MANUAL FOREWORD The EC-132 is the basic EC-130 modified for Square Root Function, Servicing the EC-132 necessitates a thorough knowledge of the EC-130. Therefore, the EC-132 Service Manual contains only the correlation of the EC-132 with the EC-130 and a description and explanation of the cir- cuits which have been added or redesigned. Any particular area of the EC-132 which is not covered, then, indicates that there is no change from the EC-130 and information regarding that area will be found in the EC-130 section of the Electronic Calculators Service Manual, Courtesy The Old Calculator Museum http://oldcalculatormuseum.com ELECTRONIC CALCULATOR 132 TEMPORARY SERVICE MANUAL SECTION 1 GENERAL DESCRIPTION Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 1 TEMPORARY SERVICE MANUAL Page l SECTION 1 - GENERAL DESCRIPTION A. SIMILARITIES TO THE EC-130 In all but a relatively few respects the EC-132 looks exactly like the EC-130. The ex- ternal differences are: the addition of a Square Root key to the keyboard; the change of CLEAR ALL key to read CLEAR DISPLAY; the addition of a pilot light located in the lower right portion of the keyboard mask; the optional addition of an Entry Counter to the right side of the CRT mask; and a new Decimal Point Position Thumbwheel. B. DIFFERENCES FROM THE EC-130 The internal differences of the EC-132 and the EC-130 are relatively minor with the exception of the addition of Square Root Function Logic. All of the logic of the EC-130 has been retained intact with respect to functions other than Square Root with the ex- ception of Clear All, which is now Clear Display and affects Registers 1 through 4 (R1-R4) only. 1. SQUARE ROOT KEY Depressing the Square Root key on the keyboard initiates certain machine operations that result in the square root of the number that is displayed in Rl being extracted and displayed as an answer in the answer register (Rl). 2. CLEAR DISPLAY KEY Depressing the CLEAR DISPLAY key on the keyboard results in the numbers in all display registers (Rl, R2, R3, R4) being discarded. This is done by inhibiting the count in A counter (Increment A) from the delay line circuits. Since only the display registers are affected, RS, the undisplayed storage register, is not cleared. 3. DECIMAL POINT SWITCH In the EC-130, the Decimal Point switch was installed in the keyboard assembly. In the EC-132, the switch has been removed from the keyboard assembly and installed under- neath the keyboard mask in close proximity to the Decimal Point Position Thumbwheel. Also, the switch is a completely new design that permits, with associated logic, decimal point position in any one of the 13 display columns, or operation with no decimal point. 4. DECIMAL POINT POSITION In the EC-130, the decimal point position was limited to one of five places. In the EC-132, the decimal point may be positioned in any one of the display columns, or operations performed with no decimal point. The Decimal Point Position Thumbwheel has been slightly redesigned to locate these 14 positions (0 and 1-13) and to operate with the new Decimal Point switch. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 1 ELECTRONIC CALCULATOR 132 8-1-65 Page 2 TEMPORARY SERVICE MANUAL 5. REGISTER 4 (R4) DATA RETENTION In the EC-130, any operation involving a shift down of data places R4 data in R3 and places zeroes in R4, In the EC-132, an operation involving shift down retains R4 data in R4 and repeats R4 data in R3. In effect, then, R4 becomes another storage register for the retention of data. However, in any operation involving shift up R4 data is discarded, as is the case in the EC-130. 6. ENTRY COUNTER The Entry Counter (optional) in the EC-132 permits a total to be kept of the number of entries of a group of entries as they are placed in the machine. The Entry Counter is a four-digit counter that is installed on the right-hand side of the CRT display. A RESET button is included to permit reset of the counter to zero before the initiation of a new group of numbers. 7. PILOT LIGHT In the EC-130 and EC-132, dividing by zero keeps the machine in an operational loop that keeps the Display blanked. In this condition there is no Display indication that the machine is on, If the machine should be covered while On, heat build-up could cause damage to semi-conductors and to other components. In the EC-132, a Pilot Light is in- stalled at the lower, right-hand corner of the keyboard mask that indicates an On condition when power is applied to the machine. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com ELECTRONIC CALCULATOR 132 TEMPORARY SERVICE MANUAL SECTION 2 ANALYSIS of OPERATION Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page 1 SECTION 2 - ANALYSIS OF OPERATION A, SQUARE ROOT MATHEMATICS The EC-130 uses a modified ''Sum of the Odd Integers''! method of extracting a square root. The method usually taught in school is not easily adapted to digital techniques, thus another system must be used. The sum of the odd integers is but one of many ways of arriving at a square root. Odd integers are the whole numbers 1, 3, 5, 7, 9, 11, etc. If such a succession of odd integers, (odd-order arithmetic progression), are added, each summation will result ina perfect square. A perfect square is a number whose square root is a whole number. The following table illustrates this. 1) +0=1=1 2) 14354 =2° 3) 1+345 29 =3 4) be34547 = 16 = 5) be de S 474 9 = 25 = 8" By adding the next higher odd order integer to each preceding summation, all existing perfect squares are produced, and none is omitted. Note that the NUMBER of odd order integers in each summation IS the square root of the sum. In example 5, there are 5 parts to the summation, and 5 is the square root of 25. This holds true for any combination of successive odd integers. As another example: l+3+5+74+9+411+ 13 =49 ls 2: 3 6 ‘Si 6; Ti Therefore, & 49 =7 By reversing this procedure, the square root can be extracted. In this case, we SUBTRACT successive odd integers to arrive at the root, starting at 1. For example: 16 15 12 7 -1 23 +5 = 15 12 7 0 (1) (2) (3) (4) Therefore, eT weil Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 ELECTRONIC CALCULATOR 132 8-1-65 Page 2 TEMPORARY SERVICE MANUAL The number of successful subtractions is the square root. If a larger number is used, more subtractions are necessary. 64 63 60 55 48 39 28 15 -1 +3 +5 -=7 +9 =I 213) 215 63 60 55 48 39 28 15 0 (1) (2) (3) (4) (5) (6) (7) (8) The square root of 64, then, is 8. This is a satisfactory method for use with perfect squares. A slight change is necessary, however, to alter the method for numbers that do not have an integral square root. Rather than count the subtractions to arrive at the root, we can apply a simple formula. In the last example, Pe 64), note that the last number successfully subtracted is 15. Adding 1 to this, (15 4 1 = 16), then dividing by 2, (16/2 =8), gives the square root in another way. Expressed as a formula: R =(n+ 1)/2, when R is the last integer to be successfully subtracted, (no over- draft), and is sometimes called the "partial root". An example will show the complete method developed so far. 100 99 96 91 84 75 64 51 36 ~ 2 = 3 - 5 - 7 - 9 -ll -13 -15 -17 -19 99 96 91 84 75 64 51 36 Lg _n+1_19 +1 _ 20 ir Mice Wil o =10 Thus, the square root of 100 is 10. The method developed to this point is perfectly valid for small numbers, but it is cumbersome for large numbers. Since the number of subtract cycles is equal to the square root of the number, an excessive length of time is necessary to complete a problem using large numbers. To avoid this, another change must be made. Starting at the decimal point, the number is divided into pairs of digits, called couplets. Beginning at the most significant couplet, the answer can be derived, one digit being pro- duced for each couplet. However, the couplets must be operated upon in a way that is somewhat different than was done in the previous examples. If the number that is to have its square root extracted is 441, it appears as 04 41 when divided into couplets. The root of each couplet will become one digit of the final square root, which will have 2 digits to the left of the decimal point. However, the root of 04, and the root of 41 cannot be combined in any way to produce the root of the original number. The following example will serve to illustrate the method used with the couplets. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page 3 The first step is to operate upon the most significant couplet by subtracting successive odd integers. 04 03 Ss 2h 03 00 Now, we do not apply the formula in its entirity. A 1 is added to the 3, but we do not divide by 2 yet. 3 + 1 =4, and this is used to begin operation on the second couplet. First, however, since the partial root for the most significant couplet is in the 10's column of the final result it must be altered slightly by multiplying by 10. The second step is to use this result, (4 x 10 = 40), add 1, and begin operations on the second couplet. 41 -41 00 Now we can apply the formula, and (41 + 1)/2 =42/2 =21 Thus, the square root of 441 is 21. In this example, there is no remainder, so the problem is completed at this point. A number that results in a remainder in the first step is treated in much the same manner. For example, let us extract the square root of 841. Step l. 08 41 (couplets) -01 07 07 -03 04 04 05 (overdraft) (restore) In this case, 3 is the largest odd integer successfully subtracted and so becomes the partial root. Multiplying by 10 to adjust for the columnar position, after incrementing by 1, results in (3 +1) x 10 =4 x10 = 40. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 ELECTRONIC CALCULATOR 132 8-1-65 Page 4 TEMPORARY SERVICE MANUAL Step 2. The remainder above, (04), combines with the other couplet (04 41). Use the partial root, (40), again incremented by one as we repeat the odd integer method. 04 41 04 00 03: 57 03 12 02 65 ~ 41 - 43 - 45 - 47 - 49 04 00 03 57 03 12 02 65 02 16 02 16 Ol 65 01 12 00 57 * §1 - 53 ~ 55 00 57 Ol 65 Ol 12 00 57 00 00 The last number successfully subtracted is 57. Again applying the formula: R =(n + 1)/2 = (57 + 1)/2 = 58/2 =29 Thus, the square root of 841 is 29. The method that has been developed up to this point is easily implemented by typical digital techniques. For a machine similar to the EC 130, however, it will require too much time to be a practical method. The final step of dividing by 2, which can add as much as one second to the total time required, is to be avoided if possible. The following procedure can be used to eliminate this step. The previous examples used successive odd integers in the subtraction process, as 1, 3, 5, 7, 9, etc. The final step in the process is the division by 2. The same end result can be produced by separating each of the above subtraction cycles into 2 steps. The table below shows how this can be done. Note that for each normal subtract cycle there are 2 subtract cycles in the modified system. The first half of the subtract pair uses the pre- vious integer developed in the prior step. (In the first subtract cycle this is of course 0.) The second half of the subtract pair uses the same integer with 1 added, (incremented by 1). Thus, in the modified method, the first subtraction is by zero, and the second subtraction is by 1, (0 + 1). The first half of the second pair subtracts a 2, (1 + 1), and so on. NORMAL METHOD MODIFIED METHOD Subtract cycles Odd integer Subtract cycles Odd integer 1 1 lst i - (1) - = pair +1 1 3 B 1 2 S 2nd pair 4 (3) l1+1 =2;2+1 =3 5 2 3 5 3rd pair 6 (5) 241 =3;53 42 =5 7 (7) 3 a 7 4th pair 8 341 =44543 =7 9 at 5 9 5th pair 10 (9) 441 =5;5+ 4 #9 Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page 5 Since there are twice as many subtract cycles as before, it is not necessary to divide by 2 at the final step. The last successful subtract IS the root by this method. A complete example to 4 significant digits in the root is given below to illustrate the way the method works. ee ll 181 in a 01 Subtract | 00 Subtract \0 —(l moved left one place) pair (1) Ol pair (1) Last fu (add 1) 11—— (add 1) successful 00 Remainder 60 subtract I Ol Subtract (Overdraft) pair (3) Ks (Restore) s — (add 1) sntract } 2 pair (5) 25 Last vhs — (add 1) raccessutl/1 12 —Remainder subtract 13 (Overdraft) (Restore) The last successful subtraction yielded the number 13, and the square root of 181 is 13 plus a decimal amount. This decimal amount can be found by continuing the subtractions using another couplet (00) and whatever remainder is left, in this case 12. To illustrate, using remainder 12: Remainder Couplet added 1200 (13 moved left one place) Oa ewes | mag 130 pair (1) 1070 i _131——(add 1) 939 | ane 131 pair (3) 808 i 132 ——(add 1) 676 Subtract \ pests 1328, pair (5) 544 133—— (add 1) 411 Subtract } 133 pair (7) 278 Last successful _- 134 ——(add 1) subtract (pair) 144 —— Remainder 134 10 135 (Overdraft) (Restore) Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 ELECTRONIC CALCULATOR 132 8-1-65 Page 6 TEMPORARY SERVICE MANUAL The last successful subtraction yielded the number 134, which properly decimal aligned would be 13.4. A closer approximation of the square root of 181, then, is 13.4. If more decimal places are desired, then another couplet (00) is used with the remainder each time for each decimal place. To illustrate, using remainder 144: Remainder moa Couplet added 14400 Subtract 1340 ——— (134 moved left one place) pair (1) } <= toes ~_ 1341 ——— (add 1) 11719 Subtract 1341 pair (3) }—<— ise ~ 1342 (add 1) ~ 9036 Subtract 14 pair (5) 694 1343, (add 1) 6351 Subtract eee 18 pair (7) ae 5008 1344 (add 1) 3664 Subtract | = 1344 pair (9) tes. S500 Last iat ee rls (add 1) subtract 975 Remainder 1345 (Overdraft) (Restore) The last successful subtraction yielded the number 1345, which properly decimal aligned would be 13.45. A closer approximation of the square root of 181 then is 13.45. If more decimal places are desired, then another couplet (00) is used with the remainder to give another decimal place. Addition of couplets and using the remainder each time can be used to give any desired degree of decimal accuracy. In the foregoing illustration of square root, the odd integers were found by successively using the last number successfully subtracted as the first step in each subtract pair cycle, then adding 1 for the second step of the cycle. The odd integer can also be found by adding 1 to the last number successfully subtracted in the first step of the new subtract cycle, and for the second step using the last number without adding 1. In other words, mathematically it does not matter in which step of the subtract pair that the 1 is added; the sum of the two steps will still result in the next odd integer. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page 7 To illustrate using 25: 25 24 24 Ze - 1 - 0 - 2 - 1 24 24 22 21 Subtract ae, pair (1) (3) 21 18 16 12 a} 2. -4 = 3 18 16 12 9 9 4 £5 na 2 a 0 ee This is the method used in the EC-132 logic. In the first step of each subtract cycle 1 is effectively added to the last number successfully subtracted, without, however, affecting the retention of the last number. As the second step in each pair, the retained last number is subtracted. If both pairs of subtracts are successful, then 1 is directly added to the last successfully subtracted number, which then is used in the next subtract cycle. It is important to note that each subtract in a pair of subtracts must be successful before the number representing the last successful subtract is actually changed. In general terms, the EC-132 handles the square root problem as follows. The number begins in RI and the Square Root key is pressed. First, Rl, R2, R3, and R4 are shifted up to put the number in R2, then R1 and RO are cleared out. R2 and R1 are then shifted to left twice to put a couplet into Rl. Next, the subtract operation begins with the Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 ELECTRONIC CALCULATOR 132 8-1-65 Page 8 TEMPORARY SERVICE MANUAL answer (the odd order integer) being developed in RO. The subtract cycle continues until there is an overdraft, then the overdraft is cleared out by addition, and another couplet is shifted into Rl. For every couplet that is shifted into Rl, RO is shifted left once. Thus, there is always one digit in the answer for each couplet in the original number. The answer is thus developed, digit by digit, in RO. At the end of the problem, R3 and R4 are shifted down, and RO is shifted up into Rl; these operations are done simultaneously, so it takes only one pass through the delay line. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page 9 Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 ELECTRONIC CALCULATOR 132 8-1-65 Page 10 TEMPORARY SERVICE MANUAL [Bec iN] [rca } SET FUNCTION FF'S [recs] IPC SETS TO 2 OR 4 [recs | T Pp CLEAR RO UNCLAMP EPC = INHIBIT DISPLAY as ‘ee ‘i. tae wet SET DPS ; DECIMAL ALIGN RESET OPS DPC SETS TO 16'S ——— SHIFT UP RI-R4 ‘ COMP, OF D. : (VIA 1173) Pos — [pc7 ] [pce ] [ecs | [eca | SHIFT R1 LEFT SHIFT Ri LEFT INCREMENT DPC ss Ss; Be Ree = INCREMENT DPC - Suet’ SS: CEES | (via 1162) _ [rce ] > Ri -(RO+1) [pcs ] PC STEPS ots“ Ser set YES PC STEPS 9 TO 14 7 11708 a “= : ) (VIA 1172) [ PC 10 | i ia R1i-RO | [Pc 1] [ RO+1 REC COF SET? YES. (VIA 1172) eae : a NO YES NOTE: ——+—{ DPC ZERO? YES NO IN PC2 — Dec. Pos. odd, DPC sets ele OPS SET? Jy to 4. — Dec. Pos. even, DPC sets { < SET_OPS . to 2. ] | DPC SETS TO 16'S P. OF OD. , IN PCB ~(RO#)is via Corry FF set, | add RO To Ri | A I which sets D Cntr to 9. IN PC11 —- RO#1is via 0-057, which PC 13 sets Al FF. | NO LOGIC ACTION | IN PC14 —(RO+1)is via 0-079, which adds 1 to A Cntr. R1i+(RO+1) and Shift RO Left are accomplished in [Pci the same line pass. pete DPC ZERO? YES YES -——+—(__ pps set? aT = SET DPS ra DPC SETS TO 16'S COMP. OF D. POS. Ri +(RO+1) YES - NO SHIFT RO é@ STEPS 14 TO XY = ZERC! LEFT 3 (VIA 1163) PC 15 SHIFT UP RO TO R1 HIFT DOWN R3 @ R4 RESET CF CLAMP EPC TO O (VIA ECFD4) PCO ESET FUNCTION FF' SQUARE ROOT FLOW CHART ENABLE DISPLAY D-132-5W Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page ll B. SQUARE ROOT FLOW CHART The Square Root Flow Chart is a graphic analysis of the logic operations of the EC-132 Square Root function. The Flow Chart is divided into blocks that contain pertinent major steps in the logic operations. Since the Square Root function is a sequential operation that is controlled by the Phase Counter steps, major areas of the logic are designated as to the PC step in which they occur. The explanation of the Flow Chart is based upon the fact that the Service Technician is already familiar with the functional operations of the EC-130. Most of the logic operations in Square Root function are the same as in other functions of the EC-132. The differences lie in the sequence of operations, and the Phase Counter step in which they occur. There- fore, those operations that are the same and which are already understood will be mentioned briefly, if at all. SQUARE ROOT - BEGIN Square Root begins with depression of the Square Root key which closes Square Root reed switch and Common Function reed switch. The reed switches, in turn, initiate KBD, and en- able Square Root and CF FF's. DPS set and DPC set to 16's complement of the decimal position are exactly as in other functions. SQUARE ROOT - PC STEP 1 Display is inhibited by PSZ3 False at A-256 in the Display Logic. This is the same as in the EC-130 except for the gate number. Decimal Align is controlled by. O-075 which controls MAI1L3 True (Align R1 left). SQUARE ROOT - PC STEP 2 DPC sets to either 2 or 4, according to whether the Decimal Point switch position is an odd number or an even number. The logic of this setting is explained in Decimal Point Counter logic discussion. RO is cleared of data by two operations. First; RO data from the Delay Line is inhibited from incrementing A Counter by RCRO3 True at O-181. RCRO3 is developed by I-074 controlled by 0-073. PC81, PC41, PC22, and PCll specify PC step 2, and TRO4 specifies RO time. When all inputs to O-073 are False, output is False and is inverted True by I-074, designated RCRO3 (Clear RO). Second; RCRO3 True makes CRD9 True via O-169. CRD9 True resets D to zero and destroys R4 data, which otherwise would be placed in Rl. DPS is reset during PC step 2 by RCRO3 True at input 1145 on the reset input of DPS FF. Rl through R4 shift up, which clears Rl for use in the Square Root operation, is con- trolled by O-072. RSUQ6 False from O-072 makes RSUL3 True from [I-129, which in turn enables A to D and D to B shifts from Rl through R4 time (TFG1 on 0-072). Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 ELECTRONIC CALCULATOR 132 8-1-65 Page 12 TEMPORARY SERVICE MANUAL SQUARE ROOT - PC STEPS 4 & 6 The net result of PC steps 4 and 6 is to shift R2 left by couplets (2-digit groups). Shift R2 left is controlled in both PC steps by 0-068. PC81, PC42, and PC1l1 will be False during PC steps 4 and 6. When all inputs to O-068 are False, output is False and is inverted True by I-069, designated ML2Q3 (Shift R2 left in Square Root). ML2Q3 True is applied through O-085 to I-086 and Inverted False, designated M2L4. M2L4 False enables O-126. TFE2 and TFF1 False at O-126 specify R2 time, and TCX5 specifies column times. (For TCX5 logic, see Register Expansion discussion.) When all inputs to O-126 are False, the output is False, designated RS2L6 (Shift R2 left), RS2L6 False applied through A-128 to I-129 is inverted True, designated RSUL3 (Shift Up or Left). RSUL3 controls shifts left of R2 through O-150 and O-154. SQUARE ROOT - PC STEPS5 & 7 The net result of PC steps 5 and 7 is to shift Rl left by couplets. Shift Rl left is con- trolled in both PC steps by 0-066. PC81, PC42, and PC1l2 will be False during PC steps 5 and 7. When all inputs to O-066 are False, output is False and is inverted True by I-067, designated ML1Q3 (Shift Rl left in Square Root). ML1Q3 True is applied through O-087 to I-088 and inverted False, designated M1L4. MI1L4 False enables O-123. TR14 specifies Rl time, and TCX5 specifies column times. When all inputs to O-123 are False, the output is False, and is designated RS1L6 (Shift Rl left). RS1L6 False is applied through A-128 to I-129 and inverted True, designated RSUL3 (Shift Up or Left). RSUL3 controls shifts left of RI through O-150 and O-154. Each shift of Rl left increments DPC by 1 through O-102 at the toggle input of DCl. DSZ3 False specifies DPC not zero, and MIL4 False specifies shift Rl left. When HOME] goes True at O-102 with all other inputs False, output of O-102 goes False to True and in- crements DPC by l. SQUARE ROOT - PC STEP 8 To produce the desired mathematical result, RO data is incremented by 1 before sub- tracting the data from Rl. Since a subtract is a complementary add, subtract is accom- plished by counting in D Counter to take the complement. The complement is then shifted D to A and R1 is added. Incrementing RO data (RO + 1) is simply accomplished by setting Carry FF via 0-064, which controls the development of ASCQ3 True (Set Carry in Square Root). Carry FF being set enables AC gate 1303 at set input of D5 FF, which then is set by CRD9 at C1IROBI5 time (before C2RO data is counted in D Counter). The net result, then, is that the count in D starts from 9, or 1 is effectively added to RO data. It is important to remember, however, that RO data is counted into A Counter and into D Counter simultane- ously. When the D to A shift occurs, which places the complemented RO data in A, an A to B shift is generated which preserves the RO data unchanged in the data sequence. Subtract (RO - 1) from R1 is partially accomplished by counting RO data in D Counter and shifting Dto A. The final step in the complementary addition is accomplished by counting Rl data in A on top of the complemented RO data. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page 13 SQUARE ROOT - PC STEP 9 The subtract cycle in PC step 8 may leave Carry FF set at Home time, which would set COF FF and indicate an unsuccessful subtract (overdraft). If this occurs, the number in Rl must be restored. Therefore, COF set is used as a decision point at the beginning of PC step 9. If COF is set, PC steps to 14 at the end of PC step 9 via 1172 on PC4 FF set input. This step jump is covered in the Phase Counter discussion. The logic action in PC step 14 is to restore the number by adding Rl to (RO +1), which is the opposite of PC step 8 subtract cycle. This addition will be covered in PC step 14 discussion. If COF is not set, which indicates a successful subtract cycle, the Phase counter steps to 10. SQUARE ROOT - PC STEP 10 In the discussion of Square Root Mathematics it is pointed out that the subtract cycles are carried out in groups of two, which eliminates the last step of dividing by two. The first subtract cycle adds 1 to RO data, and then subtracts. The second cycle subtracts RO directly. Rl - RO is a straight complementary addition as in a usual subtract problem. Rl - RO is controlled, exactly as in PC step 8, by O-056 which develops MSU4. MSU4 then controls a normal complementary add cycle, which is a subtract. The only difference between PC step 8 and PC step 10 is that in step 8 one (1) is effectively added to RO data as a part of the subtract cycle, and in step 10 no addition of 1 to RO data takes place. SQUARE ROOT - PC STEP 11 The subtract cycle in step 10 may leave Carry set at Home time, which would set COF FF and indicate an unsuccessful subtract (overdraft). If this occurs, the number must be restored. Therefore, COF being set is used as a decision point at the beginning of step 11. If COF is not set this indicates a successful subtract, which is indicated in the data by a direct addition of 1 to RO data. This is controlled by O-057, which develops RIAQ6 (In- crement A Counter in Square Root). RIAQ6 is inverted True by I-139, designated ASA13 (Set Al FF). ASA13 enables AC gate 1291 on A Counter Al FF. When A Counter is reset to zero by CRAY just before RO data is counted in, Al FF becomes set which adds 1 toA Counter. Then, when RO data counts in on top of the 1 in A Counter, effectively 1 is added to RO data, which indicates the successful subtract. When COF is not set this indicates not only a successful subtract but a possibility of more successful subtracts. Therefore, the Phase Counter steps to 8 to perform another subtract cycle. Step 11 to 8 is controlled by gate 1176 on PC4 FF and is explained in the Phase Counter discussion. If COF is set, this indicates an unsuccessful subtract (overdraft), and the number must be restored. This is accomplished in step 12. Step 11 to 12 is controlled by gate 1172 on PC4 FF, and is explained in Phase Counter discussion. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 ELECTRONIC CALCULATOR 132 8-1-65 Page 14 TEMPORARY SERVICE MANUAL SQUARE ROOT - PC STEP 12 In step 2, DPC becomes set to 2 or 4 according to the Decimal Point switch setting. When DPC counts to zero from the setting in step 2, it indicates that all data has been shifted out of R2. If DPC is counted to zero in PC steps 5 or 7, then DPC sets again for answer align, if not previously set. Thus, DPC zero is a decision point at the beginning of step 12. If DPC is not zero, RO is added to RI, which restores the number. Add RO to Rl is controlled by O-049 which controls MAIQ3 True (Add in Square Root). MAIQ3 True re- sults in the inhibit of reset A, as in a normal add. If DPC is zero and DPS is set at this time, this means that DPC was previously set for answer align. The number in RI is then restored by the Add RO to RI cycle via O-049 as previously explained. If DPS is not set, then the DPC becomes set for answer align and then Rl is restored. The logic of the answer align setting in Square Root is covered in DPC discussion. SQUARE ROOT - PC STEP 13 There is no logic action in step 13 and the next Home time steps the counter to 14. SQUARE ROOT - PC STEP 14 As in step 12, DPC zero is a decision point to indicate the necessity for answer align. If DPC is zero, which could occur in steps 5 or 7 by incrementing DPC, then DPC sets for answer align via DPS set as covered in DPC discussion. PC step jump 9 to 14 was determined by whether COF was set, which indicated an unsuc- cessful subtract. The number then is restored in step 14 by adding Rl and (RO + 1). This is the reverse of the operation that occurred in step 8 which produced the overdraft. (RO +1) is controlled by O-079 which controls the development of AIRQ3 True (Incre- ment A Counter in Square Root). At ROBI15 time an increment pulse is applied to A Count- er which increments the RO data by 1, thus (RO + 1). Add R1 to (RO + 1) is a normal add which is accomplished by inhibit of Reset A (CRAY False) at ROB15 time, which leaves RO data (incremented by 1) in A Counter. Then R1 data counts on top, which adds R1 data to the RO data left in A Counter. This is controlled, as in PC step 12, by O-049 which develops MAIQ3 True. Again, DPC zero is a decision point that decides whether to step to PC15 or to shift RO left and step to PC3, which starts another subtract cycle. If DPC is not zero, DSZ3 will be False at O-125 and enable the gate. ESQ2 specifies Square Root function; PS144 specifies PC step 14; TCX5 specifies column times; and TRO4 specifies RO time. When all inputs are False, the output is False, designated ROLQ6 (RO left in Square Root). ROLQ6 through A-128 is inverted True by I-129, designated RSUL3. RSUL3 controls shifts left through O-150 and O-154 for RO time, which shifts RO data one column left. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page 15 PC step jump 14 to 3 is controlled by 0-008. ESQ2 specifies Square Root function; PS144 specifies PC step 14; and DSZ3 False specifies DPC is not zero. When all inputs to 0-008 are False, output is False and is inverted True by I-009, designated PJQ33 (PC jump to 3 in Square Root). PJQ33 True enables an AC gate which is common to the reset inputs of PC8 and PC4. When HOME! at O-030 increments the Phase Counter to PC step 15, the same HOME] at the AC gate resets PC8 and PC4. The counter ends up with PC8 reset, PC4 re- set, PC2 set, and PCl set, which is PC step 3. This can only occur if DSZ3 is False at ©-008, which means DPC is not zero and the arithmetic is not completed. If DSZ3 is True at O-008, this means that DPC is zero and the arithmetic is complete. HOME 1, then, increments the PC to step 15. SQUARE ROOT - PC STEP 15 In PC step 15 the answer has already been developed by incrementing RO and answer align. The answer then must be shifted to Rl for display. Shift up of RO is controlled by O-124 which develops RO1Q6 (RO to R1 in Square Root), RO1Q6 through A-128 is inverted True by I-129, designated RSUL3. RSUL3 through O-150 and O-154 controls shifts that place RO data in D Counter. O-280, which develops R1OQ6, develops shifts that place the RO data from D Counter to Rl. The result of O-124 and O-280 together is to shift up RO data into Rl. To place significant data in R2 in PC step 15, R4 and R3 are shifted down by one register. Shift down is controlled by O-112, which develops RSDQ6 (Shift down in Square Root). RSDQ6 False through A-113 is inverted True by I-114, designated RESD3 (enable shift down). RESD3 through O-143 and I-144 enables A to C shifts for registers 3 and 4, which shifts R3 and R4 down one. It should be remembered, however, that R4 data is only repeated in R3 and R4 data is not destroyed. (See R4 Data Retention discussion.) In the EC-132, the only way in which the PC returns to zero is by being clamped to all FF's reset by ECFD4 True. This is accomplished by reset of CF FF at the end of PC step 15. AC gate 1104 at the reset input of CF FF is enabled by PS153 True during PC step 15. HOME] at this gate at the end of step 15 resets CF, which makes ECF] False at O-022. ECD1 is also False at O-022. When both inputs to O-022 are False, output is False and is inverted True by I-023, designated ECFD4. ECFD4 True clamps all PC FF's to reset. When CF FF resets, ECF2 goes True and resets DPS FF, and completes the logic action specified for PC step 15. SQUARE ROOT - PC STEP 0 Logic action in PC step 0 of Square Root is the same as in all other functions, and is the same as in the EC-130. Reset of function FF's, in this case Square Root FF, is accom- plished by ERF3 True. Display is enabled by PSZ3 (Phase Step zero) True at A-256 in the display logic. Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 Page 16 ELECTRONIC CALCULATOR 132 TEMPORARY SERVICE MANUAL EC-132 PC TRUTH TABLE 8-1-65 OTHER Mi PC SQUARE FUNCTIONS DIVIDE 4 a ROOT —__, ; : i | 4161—STEP1-10 IN M+D 1173—STEP 3-4 IN SQRT oltlolo| 2 4162—STEP7-8 IN SQRT — STEP" -12 IN M+D 4jijojo| 3s=<— 4163—STEP14-3 IN SQRT 4175— STEP14 -11 IN. M+D ololalo| 475 alelelo ECFD4 4471—STEP1-14 EXCEPT M-D-@Q 1476- STEP11-—8 IN SQRT MS Tolalalol ie 41 72—STEP 9-14 IN SQRT 1141110] 7a "S —STEPN-12 IN SQRT "71 o}o}o}1) sans tJolols| 9 4.7. o}s}ol1] 40 ha: mire V4} O14) 4155 ZS.tololala| sei N75 alolal4 13 | M2LM3 Esa2 —- O;1;41]4] 14 — =F io stalaia]} 15 MS0S3 PE4FS esi Ps33_| oo7 Pc4t eces | }_Po41 n61_1 PCS. MAIS (— oa pce 1162 aa =< 4173 MALO3 _| PICS "76 mar3 | reso HOME Pci2 ‘ “75! _| pose 1163 |_.pcs2 — 4190 1180 peoe2 MMDL3 1170 1160 HOME4 HOME 1 pS al | ECD 3 k osz3_ jr |__J] 009 x |ecro4) PS144 | aoe t , 023 + + ECF4 one Pcs 5 Pcs2 4 PC 41 Ps33 Pc42 o Psi44 ACOP! Pc22 — << —— pc22 — pS ° —_— PCat note om " 043 044 pcan a PSZz3 PC12 | o70 pet_| 042 pcat | 038 P3154 PCH 037 Pce2 2. PCse . oe PS153 EC-132 pc22 | cy ere PHASE COUNTER LOGIC pcte _| o39 0-132-63 Courtesy The Old Calculator Museum http://oldcalculatormuseum.com a. 8-1-65 ELECTRONIC CALCULATOR 132 Section 2 TEMPORARY SERVICE MANUAL Page 17 C. PHASE COUNTER (PC). The Phase Counter, formerly called the Entry Phase Counter (EPC) in the EC-130, is a group of four FF's connected to give a total binary count of sixteen (16). Reference to the Function Flow Charts in the EC-130 and the Square Root Flow Chart in the EC-132 shows that logic actions are controlled by specific Phase Counter steps. The logic use of the counter settings requires certain step jumps and progressions. These steps and pro- gressions are discussed as follows. 1. UNCLAMP PHASE COUNTER. During Idle, the Phase Counter is clamped to zero. One of the first actions in any function is to unclamp the counter. This action is exactly the same as in the EC-130 except for the gate numbers. The signal name ECFD4, is the same and the action of ECFD4 in clamping the counter to zero when True and unclamping the counter when False is the same as in the EC-130. 2. INCREMENT PHASE COUNTER. The Phase Counter in the EC-132 is incremented in the same manner as in the EC-130 except for the gate number that develops PIC5, which in the EC-132 is 0-030. The same logic signals are also used. 3. FUNCTIONS COMMON TO THE EC-130/132. Because the EC-130 and EC-132 have most functions in common, and the logic of these functions is the same in each machine, the operational sequence is the same. The only differences will be that a given operation will be ina different Phase Counter step. The diagram illustrates the correlation between similar steps in the EC-130 and EC-132. CROSS-CORRELATION OF EPC STEPS ALL FUNCTIONS EXCEPT SQUARE ROOT EC-130 EC-132 v 1 ‘ V STEP 1 TO 2 STEP.1 TO 10 _——T 10 3 11 v v gq STEP 1T06 STEP 1 TO 14 12 STEP 6 TO 3 \ Vy STEP 14 TO 11 5 13 6 14 7 15 0 0 Courtesy The Old Calculator Museum http://oldcalculatormuseum.com Section 2 ELECTRONIC CALCULATOR 132 8-1-65 Page 18 TEMPORARY SERVICE MANUAL Since the incrementing and step jumping of the Phase Counter in the EC-132 is not the same as in the EC-130, the similar steps and jumps are explained as follows. a. PHASE COUNTER STEP 1 to 10. Ina Multiply or Divide function it takes six counter steps to complete the function. Since there are 16 steps in the EC-132, in a Multiply or Divide function the counter progression jumps from 1 to 10, which provides six (6) further steps (step 10 to step 15) to complete the function. This step jump corresponds with the counter progression from Step 1 to Step 2 in the EC-130. Phase Counter step 1 to 10 is controlled by gate 1161 on PC8 FF set input. This is an AC gate with ESQ2, which will be True in any function except Square Root, as the enable and PC21 True as the transition signal. When PC21 goes False to True at AC gate 1161 enabled by ESQ2 True, PC8 FF sets. Therefore, when the counter steps from 1 to 2, this results in PCl reset, PC2 set, PC4 reset, and PC8 set. This is the condition for step 10. b. PHASE COUNTER STEP 14to 11. Logic in a Multiply or Divide function requires a return to a previous step under certain conditions. In the EC-130 this step is from 6 to 3. In the EC-132 this corresponding return step is from 14 to 1l. Step 14 to 11 is controlled by gate 1175 on PC4 reset input. This is an AC gate with MMDL3, which will be True in a Multiply or Divide function, as the enable signal and HOME 1 as the transition signal. At the end of step 14, HOME! at 0-030 makes PIC5 True which increments the counter to PCl set, PC2 set, PC4 set, and PC8 set. This same HOME 1, however, at gate 1175 resets PC4. The new condition, then, of the counter is PCl set, PC2 set, PC4 reset, and PC8 set, which is step 11. c. PHASE COUNTER STEP 11 to 12. The design of the counter prevents the usual pro- gression from Step 11 to Step 12. Ina Multiply or Divide function this progression is controlled by gate 1173 on PC4 set input. This is an AC gate which is enabled by PE4F5 True. PE4F