Analog Computers

Manual / Guide

EAI 580 Console Manual — Chapter 6: Overload Indicators

Read the PDF (24 pp) ↗

Chapter 6 of the EAI 580 analog computer console manual, covering the visual overload indicator subsystem. The chapter explains the theory of operation for amplifier overload detection circuits (including NRPD and audio overload circuits), provides maintenance and troubleshooting procedures for the overload panel, and includes a replaceable parts list with tables for the control tray, control cards 1 and 2, and visual overload alarm assemblies (models 0.20.1018-2 and 0.20.1018-3). An appendix of engineering drawings provides schematics for the control tray wiring, control card circuits, the visual overload alarm assemblies, and the indicator panel layout.

Manufacturer
EAI
System
EAI 580
Type
Manual / Guide
Language
English
Learning track
machine reference
Pages
24
  • EAI 580
  • EAI
  • overload indicators
  • visual overload alarm
  • maintenance and troubleshooting
  • replacement parts

← Back to the Reference Library

EAI 580 Console Manual — Chapter 6: Overload Indicators

CHAPTER 6 OVERLOAD INDICATORS 6.1 INTRODUCTION The 580 is equipped with an overload warning system that provides both visual and audible indi- cation of component overloads. The visual overload indicator panel (Figure 6.1) is equipped with lamps that illuminate the least significant address digit of any overloaded amplifier, includ- ing the plus and minus reference amplifiers. The audible alarm produces a tone whenever any of the visual indicator lamps is illuminated. In addition to these indications of an overload, a logic signal connected to the patch panel goes high when an overload occurs. This signal may be patched to an Override Hold (ORH) terminal, forcing the integrators into hold when a com- ponent overloads; or patched to an Overload Store (OLS) terminal, causing the indicator to re- main illuminated after the overload is removed. -—* = ae ee OVERLOAD INDICATORS ee ea i Oe | PART OF: 0.13.0046 OVERLOAD V.M. CIRCUIT AS .'. KBul2 ‘ ys ———. | Q2 12/2 KHz lias i ' |-- 1 | | teen | Lo a Ss | ! sk | L_ _ J NOTE: ALL CIRCUITS NOT INCLUDED IN DASH LINES ARE LOCATED IN THE OLD 0.12.1607 CONTROL TRAY. CHAPTER 6 OVERLOAD INDICATORS 6.2 THEORY OF OPERATION 6.2.1 Visual Overload Indicators A simplified schematic of an amplifier overload indicator circuit connected to an amplifier stabilizer output is shown in the left center portion of Figure 6.2. The pulsating stabilizer out- put signal normally has a very low amplitude. If an amplifier overloads, the stabilizer output signal increases greatly in amplitude. Capacitor C1 couples this signal to the cathode gate of silicon-controlled switch (SCS) Ql. The SCS then allows current to flow through the overload indicator lamp, DS$1. Once an SCS begins conducting, it remains conducting until the anode-to-cathode potential is removed. Thus, if power for the lamps were supplied from a filtered de source, the lamps ‘would remain illuminated indefinitely once an overload occurred. For this reason, the over- load lamp power is supplied from a rectified but unfiltered source, except when the OVD ter- minal is patched to the OLS terminal. The voltage thus decreases to zero 120 times per second (assuming a 60 cps primary supply frequency), and the lamps are extinguished almost immedi- ately after an overload is removed. This type of circuitis used to monitor all stabilized ampli- fiers inthe computer. Ten circuits identical with that shown in Figure 6.2 are mounted on a 0. 20. 1018-3 Visual Overload Alarm etched-circuit card. The indicator lamps are mounted on the edge of the card, which is installed directly behind the overload indicator panel. A metal mask directs the light from illuminated lamps to the appropriate numbers on the panel. The overload indicator circuits for the encapsulated MDFG amplifier (which are not chopper- stabilized), are shown in Figure 6.3. The input signal to an overload circuit of this type may be slowly changing de level, rather than a pies signal. For this ini ere rather than capacitive coupling is employed in the circuit. ij 0 deed circuits that provide an amplified sana t tothe. indicato1 OVERLOAD INDICATORS rates the overload detection circuit for an MDFG unit. Each MDFG unit has a amplifiers (AR1 and AR2). The detection circuit uses a cascaded inverter network to an overload of either polarity. For example, if the output of either AR1 or AR2 exceeds volts, Q1 becomes forward biased. The low from the collector or Q1 reverse and the collector of Q2 goes positive. Conversely, if the output of either ARI or AR2 egative than about -11.5 volts, one of the diodes connected through the 13K resistor of Q2 reverse biases the transistor. In either case, the collector of Q2 goes positive, onthe 0, 20. 1018-3 Visual Overload Alarm cardistriggered, causing the associated | AR2 (SHAPING) (OUTPUT) +15V +15V 4.7K MDFG 13K ISK OVERLOAD SIGNAL OUTPUT Q2 Ql = circuit ee is shown in Figure 6.5. This = a» = p= i? = re" —_ ~~ Ee _ -_ 6h he CHAPTER 6 OVERLOAD INDICATORS .] ‘ STABILIZER OUTPUT AN f ‘ + OR— REFERENCE AMPLIFIER R2 JZ 3%) ! Ss iS a | Figure 6,5. Reference Amplifier Overload Circuit, Model 0.20,1018-2, Simplified Schematic a The audible overload alarm, together with its logic control circuitry, is shown in Figure 6. 2. When an overload occurs, Q1 of the visual overload alarm conducts, grounding the +6 volts from the power supply through diode CR1. The base of Q2 becomes more negative than its emitter, the transistor conducts and its collector and the input of inverter 1a (pin 12) go high. With its output high, the output of inverter 1a (pin 3) goes low, and transistor Q2, located in the 0. 1s0nee Overload Card, conducts. The conduction of Q2 provides a ground path for the encapsulated oscillator circuit (located on the 0.13. 0046 Overload Card), the oscillator starts and the alarm sounds, Adjustment of potentiometer R2 varies the audible output of the unit from ners maximum value. When the audible overload alarm is heard, the operator can check the visual panel to determine which component (or components) is overloaded, BSW Rva some E overtonds: may be mt a hei 4 oil nature when a hi CHAPTER 6 if the OVD terminal is patched to the Al, the output of the Q2, Q3 NOR gate goes low when an overload occurs. This low output, Hienated SP forces all integrators into the hold mode. Since the problem is stopped at the point where the overload occurred, the overload indicator for the overloaded component remains illuminated, and the operator can check the input and output parameters for this component to determine the cause of the overloaded condi- tion. However, if any of the inputs causing the overload are removed for checking, the overload disappears, and the computer resumes operation. For this reason, the manual HD pushbutton on the keyboard should be depressed, forcing the computer mode control circuits into the hold mode. If this is done, the circuit can be checked by removing patch cords, etc,, and the com~- puter cannot resume normal operation until the overload is cleared and the OP pushbutton is de- pressed. The OVD terminal may also be used to accomplish some other function, if desired, by patching the OVD output through a differentiator to a logic component. 6.3 MAINTENANCE AND TROUBLESHOOTING | None of the overload warning circuits require periodic maintenance or adjustments. It is normal for the visual indicators to flicker when the computer is first switched on. After 15 to | 30 seconds, all visual indicators should be extinguished and the audible alarm should stop. If none of the indicator lamps light during the computer warm-up, check fuse F8 on the 0. 10. 0354 Power Supply. If it is desired to check all indicator lamps individually, remove the patch panel and place the computer in the JC mode. The indicator lamps for all the amplifiers in the com- puter should light. ‘The VDFG overload indicators may be checked by placing the slope switch for segments 1 and 2 ae each MDFG unit in the +SL position, setting the BP potentiometers for these segments fully lockwise, and setting the SL potentiometers for these segments fully clockwise. It is necessary to patch the MDFG X input to reference voltage of the proper polarity (+ refer- for +MDFG units, - reference for -MDFG units) to cause the overload alarm to light. Re- his test for all MDFG overload indicators in the computer. metal mask to expose the card on which the lamp is mounted. The card ing it forward, When the card is removed, the lamp can be checked appears to be good, check the SCS by substitution. >. CHAPTER 6 If the audio alarm fails to operate when a visual indicator is illuminated, first ensure that the volume control is not at its minimum setting. Then check the OVD terminal. If this terminal is high, the trouble is in the oscillator circuit, If this terminal is low, check pin KBP12-6 on the 0. 20.1180 Monitor Panel with an oscilloscope (see the component location diagram facing Schematic DOO 020 1180 0S). The signal at this point should be a negative-going, full-wave rectified voltage with a peak amplitude of between -0.5 and -1,0 volt when an overload is present. If this signal does not appear, check the wiring as shown in Figure 6.2. If this signal is present, use point-to-point signal tracing to locate the faulty component. To expedite your order for replacement parts the procedures below should be followed: 1. Specify the EAI part number and description of the part required. The model number and APPENDIX 1 REPLACEABLE PARTS LISTS This appendix contains Replaceable Parts Lists for the equipment described in this chapter. In each case, a brief description of the part, the EAI part number and, where applicable, a refer- ence symbol (schematic designation) is included. To enable a particular sheet to be readily lo- cated, an index precedes the individual replaceable parts lists. The category column indicates the availability of each part so that a replacement can be obtained as quickly as possible. Category "A" - The parts in category '"'A" are standard electronic items that are usually avail- able from any commercial electronic supplier. Category 'B''- The parts in category ''B" are proprietary items that are available only from EAI. If proprietary items are veplaced with items ob- tained fvom other sources, EAI cannot assume responsibility for a unit not operating within its published specifications. ORDERING INFORMATION serial number of the next higher assembly should also be included. 7 NOTE EAI is currently revising the part numbering Sys= tem. All parts effected by this neudsige aug ie tified using the new and the old number y in parenthesis), All La ry the new number. ‘The oa PARTS LIST INDEX BOnERO NC ADCUD ere gielalelecieisieis's & 5 sleieiesia 6 04 . . . Overload Alarm .......0.sss2+.005 aeleinsean oie es 3-18 3-18 3-19 6-11 6-12 ZeeRPeRRPeeRee eR Sees EBeEE EERE EP 27K ohms +5%, 1/4W (Allen-Bradley CB or equal) ITEM! REF. DEsic, DESCRIPTION EAI NO. rear. | 1 | c1-¢ Capacitor, Fixed, Plastic: 00 521.1398-0 A 220 nf +20%, 50V (Good-A1l X663F or equal) 2 | C2-(1-10) Capacitor, Fixed, Ceramic: 00 511.5473-4 | A 0.047 pf +20%, 25V (Sprague 3C15 or equal) 3 | DS1-() Lamp 00 578.0077-0 4 1 Q1-() Stabistor: 3N84 00 648,0016-0 5 | R1-() Resistor, Fixed, Composition: 00 625.0472-0 4.7K ohms +5%, 1/4W (Allen-Bradley CB or equal) > | R2-() Resistor, Fixed, Composition: 00 625.0273-0 | A } 2.2K ohms +5%, 1/4W (Allen-Bradley CB or equal) DESCRIPTION EAI NO. *CAT. tu |Capacitor, Fixed, Plastic: 00 521.1398-0 | A 220 nf +20%, 50V | | (Good=-A1l X663F or equal) (1 thru |Capacitor, Fixed, Ceramic: 00 511.5473-4 | A 47 nf +20%, 25v (Sprague 3C15 or equal) Lamp 00 578.0077-0 | B |stabistor: 3N84 00 648,0016-0 A 1 |Resistor, Fixed, Composition: | 00 625,0472-0 | A a | 4.7K ohms +5%, 1/4W } (Gllen-Bradley CB or equal) \\ |Resistor, Fixed, Composition: 00 625.0222-0 | A APPENDIX 2 DRAWINGS number of each unit or component, the type of acceeen and the associated aan ving nu The drawings are bound into the manual in the order listed under the index Drawing Number column. EAI drawings are prepared in accordance with standard drafting practices for electro cal and electronic equipment. All symbols are in accordance with current government ards. Unit or Component 0. 12. 1607 Control Tray 0.12. 1615 Control Card 1 0. 12.1616 Control Card 2 NMOTES = I. LDMLEBS: OFM EPWTSE SPELAETED * a) wires 10 BE 22 PPL 2 @ 2ewores LOcATIAW ae cOMTACTS ferent Go) PBR BbTAE FF = ti Nay 8 SS N TR RS] TPSPieys ©o ®©9 Seba ne yadda . RR 8 | BISRVISTIL LLY wwe sae ves E t 8 | | > ais » ha CORR OLORORORS) (TOROROTORORONC) i i (DEAITIF HT LIT Kf2, BEND TABS 7O SECURE 1 Gne01, 72) cown. BtocKe cann % CERT OFF FOR CLARITYITEM™2) : : SEE OETAK. “8” FOR MOUNTING — Ls Jf C3 1 | Z WOOOQDOOOO © © © 09 990900QR068 | | +e re . GSHEESS OTHERWISE SPECK? A) RPESCETORD SOE TD Yo» 7 A) BPDES BLE ACEI OLA oO: LD) TRANSISTORS ARE 2 FELS LAT ~ 20 ©8G o750 4) 2 ON ALL fel 5s FA e GOES 7 1a GRO ¢ FUN 0,12.1616 Control Card 2 orwemaisé SPECHHIED) ee ESNS TOR HEE 2S, COW: =sr *c ow ele a OW Ae sos ie Aue FINITE GOES 70 FEV. tah ed et et ee TT 40 7 19948 a =. val ra SO S101 0208 | 4816 2 ee eeave ‘sie le Be! Zs L} = BraN con sive yos iste] = . wRln aMet tsi § ~e {) | |e] sas a. ws = ; = —- — = = | L/6/ ry ltt y i iy fowans mel = HSIN eyes! = — 4. a PTL JFS VAN t * afer See, ME Fe : WIP IP DIAC 2wASIA 6e7'y Ge ES EE oe wuae | ; tees ae. ¥} 9 LAIINF LN MONS Sh A3SNaPr MEN 'HONVEE SNOT ; | -ONI'S31VID0SS¥_3INO19373 | ay } a SR WARE THRE £0 TOL. ee? eo Fee | fe eT wes OR Re ae BONVHRTOR SRNO HO) FONE 2 pet et A PONWRIOWEND S26 WE DEY EXOrEN Ee ~S < S ® ® n Ci * ILS ELIS LER 2 OS LE ie er AF | ae 10970 Na? FP NVE AIA AA NOL OW LIM : TIN wr ater NIHM SOM IWR SIA UNFPA fad oe €h ot | Catiesem) + coarse sowl o Ul sem e¥ 22 ers 6 Fs) Val ee corer &- FIP ee Ww oa Ps ee ¥ N 427 Sew ts ov lo a ee ee ee A, Lrigttl 7 5,7 + L,472dN/ - > oy c7Sz FW % 47g ———— Sta — $ tulrew —D 9 finan ia PP APL PDN YY as on aes Att FP * SRNL O/ LY Fd. nt RAL Ow ee eey ws 2a fin” FPSO PFs Pee ol Pek A (AAL, DH D J oe 6 oe LE 6 | &) OP mre 4 rr S w x Be \ aa tag : % ts phy , tet ‘ , “it ‘ ' vane , } wh ‘. ~ ; “ i ! ’ 2 ge, * is t eek” =| MYL GG PIV SIOLSISIA Ss i WABI we WAP LLD SSPIN? || ISRLOWV ’ a aA aay] aNOIsIAReM ‘ow / Tworanaoud Fl| alm wos OaNYTTIe H i] 5 { SUILULE OLED AEE EF ty, |. Z pots tl as "basse thee rigs “Zz A t x é “a 2 ? she Ye “UY yy Y: Lb, ‘ alia) mo CIES ta Me, 4 hae ‘ 2 ; = ol 4 4 ay ay eg es Y bf wo” 4 ' aes “By, yHe — y r : a a oe vio Wy y (AGT vn hee g _ G Z 4 q A — OC ‘hy, <= Were OOM SS CSS Uy. N = H | a - 3 {14 fo) | | [on aaa niva nope aaa nay i 1 | i | 321s = ‘no axsn 31v38| Pit yy ty "ON “LHS ani, HSINI4 Tivw “ONI * «tt-7 tO F xx A3SHaf MAN “HONYYA SNOT VIDOSSV_DINOYLD374 GH 4ans Wittive 40 TOL, Soo Fae | 510% » Fe {0 F= x 140 FONVEIOL SHHO MI SI 2ONVISISNN #4 MY St 2OMVELOVeND SIMONE WT THY SHOISNENIO GAIs1I94S ASIMBAHLO SS3ING * ? DO Leal PT 6 Lfid(Vi SIWIL DLWIATS = ae ay, 2LpaVt PY DAAL LIOA/D sane 1 ) Pees ss eee se ss ss +" 4 000 e7 Ls) )0 00000060: V2 TES> he! A MLESS F OVERLOAD VM. CARD V2 ES OT) FE Pe | a a — -—- === +! Sl gs2e 7O0Wws — ~n ame WARNES + (018.407) a2y . wo | i Ce 3 [<34 SPM WH] | ‘4 war-we is ORM. 4 LED 7 DG Ged PT; be FP (vse) send ‘é / A CAL _GRMRED) 2 [sam ai-nwr 3 AL WOR 4 OAC Cour) bie Wed 5 = pee sv z 4 ay), va. 3 OM 7 SSS ee FO ‘ 2 wt. 3 sD iS 4 s e NOTES; 1, COMMEC TIONS BETWEEN WW), SIEGE ARE WRE JUMPERS, (420 100 0258 GP) Baws Seo PAHH dun MS (4e5r~) Coes Ore ln = = ORS E7} \ “a os) jose o55% 054 Gx A ECR MEARE ST FRONT PANEL LOL PIE 0.18, 080? fl CAB. CFOR FODETHEE AE Fr0s Poca: | _ 49 0-~~--0f} |)