English translation
Dornier DO-80 Analog Computer — Prototype Construction Documentation
This document translates an original German-language prototype engineering dossier for the Dornier DO-80 analog computer. The document contains no formal title page; internal headers are translated throughout.
Standard Configuration (Standardbestückung)
Computing Elements (Rechenstelle)
| Element | Quantity |
|---|---|
| Integrators / Summers (Integrierer/Summierer) | 8 |
| Summers (Summierer) | 4 |
| Inverters, each with two inputs (Inverter mit je zwei Eingängen) | 4 |
| Multipliers (Multiplizierer) | 4 |
| Comparator amplifiers (Komparatorverstärker) | 2 |
| Comparator relays (Komparatorrelais) | 4 |
| Potentiometers (Potentiometer) | 8 |
| — of which unearthed (davon ungeerdet) | 3 |
| Free capacitors: 1 µF, 0.1 µF each | 1 |
| Resistor network 2×1 MΩ, 1×100 kΩ | 1 |
| Zener diode network 2×10 V | 1 |
| Diode network: 2 diodes, 1×100 kΩ | 2 |
| Function switches (Funktionsschalter) | 3 |
Measuring Instrument (Meßinstrument)
Panel meter with switchable range amplifier (±15 V, ±1.5 V, ±0.15 V).
Central Overload Indicator (Zentrale Übersteuerungsanzeige)
Indicates overload across all computing amplifiers.
Control Unit (Steuerteil)
Provides the following modes:
- Rechnen — Compute (single run)
- Repetierend Rechnen — Repetitive compute
- Dauerrechnen — Continuous compute
- Pause — Pause
- Halt — Hold (IC hold)
- Rechnen mit Halt — Compute with hold
- Übersteuerungshalt — Overload-triggered hold
Compute time (Rechenzeit): adjustable 0.1 s to 110 s
Pause time (Pausenzeit): adjustable 0.1 s to 10 s
Sawtooth voltage −10 V to +10 V available as timebase for external devices.
Power Supply (Netzteil)
- Amplifier supply voltage: ±15 V, 0.7 A — adjustable, short-circuit-proof, short-circuit current adjustable
- Reference voltage: ±10 V, 50 mA — adjustable, short-circuit-proof, short-circuit current adjustable
- Relay voltage: +12 V, 0.9 A — adjustable, short-circuit-proof, short-circuit current adjustable
Specifications (Spezifikationen) — Typical Values
General
- Mains supply: 220 V / 50 Hz
- Power consumption: approx. 40 W
- Dimensions: 443 × 237 × 277 mm
- Weight: [not specified]
Power Supply Notes
All voltages stabilised, adjustable, short-circuit-protected. Short-circuit current adjustable.
Accuracy of reference voltage: approx. 1 ‰.
Computing Elements — Detailed Specifications
Integrators (Integrierer)
Operational amplifier: BB 3307/12C, short-circuit-proof
| Parameter | Value |
|---|---|
| Input voltage | ≥ ±10 V |
| Output current | ≥ ±5 mA |
| Open-loop gain | > 200,000 |
| Bandwidth at unity gain | > 4 MHz |
| Temperature drift of offset voltage | < 20 µV/°C |
| Offset current | < 20 pA |
| Offset current temperature drift | ×2 / 10 °C |
Integration network — switching via 2 reed relays, 1.5 ms:
| Component | Value | Tolerance |
|---|---|---|
| Input resistors | 3×1 MΩ, 2×100 kΩ | ±0.25 % |
| Additional feedback resistor | 1 MΩ | ±0.25 % |
| Initial condition | 100 kΩ | ±0.25 % |
| Capacitors | 1 µF, 0.1 µF | < 1 % |
Summers (Summierer)
Operational amplifier: BB 3307/12C — n.c. (same type as integrator)
| Component | Value | Tolerance |
|---|---|---|
| Input resistors | 3×1 MΩ, 2×100 kΩ | ±0.25 % |
| Feedback resistor | 1 MΩ | ±0.25 % |
Inverters (Inverter)
| Component | Value | Tolerance |
|---|---|---|
| Input resistors | 2×1 MΩ | ±0.25 % |
| Feedback resistor | 1 MΩ | ±0.25 % |
Operational amplifier: BB 3308/12C — e.c. (alternate type)
Temperature drift of offset: 50 µV/°C
Offset current: 100 pA
Comparators (Komparatoren)
Amplifier: NS LM301A
| Parameter | Value |
|---|---|
| Open-loop gain | approx. 200,000 |
| Offset voltage drift | approx. 6 µV/°C |
| Offset current | approx. 70 nA |
| Input resistors | 2×100 kΩ, ±0.25 % |
| Sensitivity | approx. 10 mV |
Maximum 4 relays may be driven.
Relay type: reed relay / changeover contact, 1.5 ms switching time.
Potentiometers (Potentiometer)
- 10-turn wirewound
- Linearity: 0.3 ‰
- Overload protection via incandescent lamp (Überlastschutz durch Glühlampe)
- Potentiometers 4 and 5 are not earthed (unearthed)
Circuit Schematics (Schaltpläne)
The document contains hand-drawn circuit schematics for all major modules:
Double Summer (Doppel-Summierer)
Two-channel summing amplifier circuit with BB-series op-amps, switchable input resistors (100 kΩ, 1 MΩ) on a common connector strip. Each channel terminates at patch panel points a1–a9 and b1–b9.
Integrator/Summer (Integrierer/Summierer)
Combined integrator and summer plug-in module. The integrator section uses reed relays (controlled by Pause/Halt/Rechnen logic) to switch between initial-condition resistor and integration capacitors (1 µF, 0.1 µF). The Betriebssteuerung (mode control) input drives the relay coil (3307/12C). Overload indication output at b6, b7. Patch points: a1–a9 on the lower connector strip; a/b rail.
Comparator Amplifier / Relay (Komparatorverstärker / Relais)
LM301A-based threshold detector. Input resistors 100 kΩ × 2. Relay driver section uses transistor output stage to drive reed relay changeover contact. Separate circuit for free passive elements (resistors, capacitors on patch points).
Control Unit (Steuerteil)
Logic circuit providing compute modes. Includes mode selector switch positions (R = Rechnen, H = Halt), relay outputs HR (Halt relay) and R (compute relay), timer inputs for Pause and Halt, overload-stop (Übersteuerungshalt) input. The circuit drives all integrator mode relays and the central overload indicator.
Timer (Zeitgeber)
Generates adjustable compute time (0.1 s–110 s) and pause time (0.1 s–10 s). Uses LM301A op-amp as comparator, 20 kΩ 1% resistors, and sawtooth generator. Output sawtooth voltage range −10 V to +10 V provides timebase for external oscilloscopes and X-Y plotters. Switch S1 selects time ranges.
Central Overload Indicator (Zentrale Übersteuerungsanzeige)
Monitors all computing amplifiers A1–A4+ via diode OR network. Output drives lamp indicator for panel display. Connected to halt logic (H, D, Rep signals).
Measuring Instrument Module (Meßinstrument — Einschub)
Panel meter with switchable range amplifier providing ±15 V, ±1.5 V, ±0.15 V full-scale. Switches: N (network), M3 (range), M4 (range selector). Op-amp: BB 3307/12C. Patch socket terminals Geh and SW.
Wiring Diagrams (Verdrahtung)
Upper Wiring (Verdrahtung oben) — Diagram 6
Shows connector strip layout with 28 conductors and 12 Fäden (fine wires), 132 contacts. Rails carry: −10 V, +10 V, −15 V, +15 V, +12 V, TR1, TR2, POT/NETZ, MESS. Open circles = wires from below; filled circles = solder points from above; squares = coderail pins.
Lower Wiring (Verdrahtung unten) — Diagram 9
Complementary lower wiring showing distribution of ±10 V, ±15 V, A+, A−, Br (bridge), Rel, and remaining signal lines. Two connector strip assemblies shown.
Individual Integrator Control (Einschub Integrierer-Einzelsteuerung) — Diagram (p.19)
Plug-in module for individual control of each of the eight integrators. The module has a connector with assignments:
| Pin group | Function |
|---|---|
| 0a–5a | Initial condition and input connections for integrators 1–6 |
| 0a→β1S, 0a→β1S, etc. | Beta (coefficient) inputs |
| 5a–1a, 6a–β1S | Feedback paths |
| 7a–α1B, 7b–α2B | Alpha (gain) inputs |
| Ms–α6, α7 | Mode-select connections |
| 12a–α16, α17 | Additional alpha inputs |
| Gen–βA | Generator input |
| 10b→β13, 15a→β10, 16b→β18 | Extended coefficient paths |
| 16a–β12, 16d–β15 | Additional beta paths |
| Gen.–βA | Generator to beta-A |
Potentiometer Module (Einschub Potentiometer) — Diagram (p.20)
Eight potentiometers (each 10-turn, 10 kΩ, 0.25% linearity) wired to patch points. Diode protection network shown. Patch terminals: contacts 1–28 along the right edge.
Mains Connection Module (Einschub Netzanschluss) — Diagram (p.21)
Connection schematic for mains input through transformer and fuse. Includes:
- Notes 1–3: Patch points a1–a6 connected to Tachobuchse (speedometer socket); switch set to grounded position; switch to chassis ground.
Transformer Module (Transformator-Einschub) — Diagram (p.13, numbered “10”)
Two boards on 70×110 mm platforms. TR2 supplies 220 V mains to primary windings. TR1 secondaries: approx. 14 V/1A, 14.5 V/1A, 12.5 V/1A, feeding ±15 V and +12 V regulated supplies. Warning note: do not cut the circuit boards — Platinen 70×110 must not be scored above.
Power Supply Schematics (Netzteil)
+15 V / −15 V Supplies (Diagrams “12”, numbered p.14)
- Rectifier bridge feeding 2200 µF electrolytic capacitor
- Regulator: SG 723C (adjustable)
- Output adjustments: (1) current limiting, (2) output voltage
- Boards: 2 Platinen 70×110
Reference Voltage +10 V (REFERENZ-SPANNUNG +10V) — Diagram “13”, p.15
- Precision +15 V derived from main supply
- Regulator: 809 type
- Trim adjustments: (1) current limit, (2) output voltage
- Output to pin 16 of wiring harness
Reference Voltage −10 V (REFERENZ-SPANNUNG −10V) — Diagram “14”, p.16
- Mirror image of +10V supply using regulator type 853
- Trim adjustments: (1) current limit, (2) output voltage
- Output to pin 17 of wiring harness
Contact Assignment — Timer + UH Module (Kontaktbeschreibung Zeitgeber + UH)
20-pin connector assignment:
- Geh (chassis ground)
- tp (pause time)
- zt (compute time)
- A1
- ∫L,12V (integrator 12V)
- ±Rel (relay voltage)
- Ha (halt output A)
- Ra (reset A)
- ±Ref (reference voltage)
- +12V
- A− (negative supply)
- A+ (positive supply)
- +10V
- −10V
- +15V
- −15V
- ±V (voltage)
- H (halt)
- D (?)
- Rep (repetition)
Mechanical Construction (Gehäusemontage und Mechanik)
Housing (Gehäuse) — Drawing 1
Overall chassis dimensions: 138 × 91 mm cross-section; internal slide slot at 87 mm; lower slot at 60 mm; slot width 69 mm. Module slides to be mounted from top.
Housing Cutout for Control Module (Ausschnitt im Gehäuse f. Steuereinschub) — Drawing 2
Side-profile cutout dimensions: 38 mm wide, 26 mm + 2 mm; 24 mm + 12 mm lower cutout; overall depth 10 mm + 12 mm. Side opening for control slide insertion.
Module Side Rails (Seitentale für Einschübe) — Drawing 3
L-profile rails, 70 mm long × 25 mm × 10 mm, material 2 mm thick; 5×Ø2.8 mounting holes at top and bottom; 2–25 mm flange height; 2 pieces per module slot (Befestigung am Gehäuse = fastened to housing).
Connector Strips — Upper (Steckerleisten oben) — Drawing 4
Plan view showing connector strip layout with spacing: 10, 30, 45, 85, 45, 305 mm positions; 400 mm total length. Rails: MESS (measure), POT/NETZ, +12V, TR2, TR1, +15V, −15V, +10V, −10V, β (patch bus).
Connector Strips — Lower (Steckerleisten unten) — Drawing 5
15 connector strips total; 40, 30, 25 mm spacing from rear; 25, 1, 1, 25, 1, 1 spacing between inner strips. Card guides provided.
Module Fastening — Pot, Meß, Rear Cover Plate (Befestigung Einschub Pot, Meß, hintere Abdeckplatten) — Drawing 7
- POS 1: Hex spacers M3, 6 mm long, approx. 7 pieces; 8 mm long, approx. 8 pieces; 6 mm, approx. 6 pieces.
- POS 2: 6Ø Brass plate 1 × □ 6.5 mm.
- Brass M3 bushings + M3 screws.
- Fastening: 20 + 4 screws total.
Meßinstrument Connector Strip Fastening — Drawing 8
Kleine Steckerleiste (small connector strip). Fastening via Federkontaktstift (spring-contact pin). M26 brass rod 6 mm, 2 pieces per instrument. POS 2: M3 screw, 5 mm, 5° taper, 4.35 mm head. 36 mm length rod.
Assembly Notes — Housing (Bemerkungen zur Gehäusemontage)
- Mount vertical channel sections on front plate; leave clearance for mounting-screw heads.
- Pre-assemble housing side panels.
- Horizontal channel profiles on front plate: make slightly longer than 420 mm (207.5 M4).
- Drill mounting holes for height-adjustment profiles before assembly.
- Mounting holes for height-adjustment profiles will need to be filed slightly.
- Fasten side panels for inner modules before housing assembly.
- Mount large connector strip housings so that the upper terminal can still be used.
- Let guide rails project on all sides as far as possible; front left may extend only one hole.
- Fasten card guides for M1, M2 with M2.6.
Front Plate Drawings (Frontplatten)
Frontplatte Potentiometer-Einschub — Drawing (p.34)
Panel dimensions 685 mm × 25 mm strip. Contains 8 holes for potentiometer knobs (10-turn, Ø25 mm) and 2×25 holes for Tuchbuchsen (terminal jacks). Two additional potentiometer positions (Ø46 mm). Length 312 mm inner + 148.5 mm.
Frontplatte Steuereinschub — Drawing (p.35)
Narrow vertical panel, 38.5 mm wide × 137.5 mm tall; inner cutout 19 × 103 mm; 3.5 mm border; 3.5 ø holes at corners.
Frontplatte Meßinstrument — Drawing (p.36)
Panel 685 mm wide × 87 mm tall. Inner cutout 32 × 67 mm (meter window). Side controls: Ø 40 mounting holes for two selector switches, Ø 40 for network switch; dimensions 55 mm, 70 mm from edge.
Frontplatte Integrierer-Einzelsteuerung — Drawing (p.37)
Panel 207.5 mm tall; 4×16=64 Ø 8.2 mm holes for the integrator control switches (individual Hold/IC control for 8 integrators × 2 rows of buttons). Additional 12×7.12 terminal holes at top. Lower 5.80 mm row of 3 banana jacks.
Frontplatte Netzanschluss — Drawing (p.38)
Panel 191.5 mm tall × 83 mm wide. Features: large central terminal (Ø circle, +), fuse holder, mains socket, and indicator lamp. Row of 24 + 12 + 12 terminal holes at 2 mm spacing. Bottom: 3×Ø large holes; multiple ø contact points.
Cutout — Row of Keys (Ausschnitt f. Tastenreihe) — Drawing (p.32)
Cutout 36 mm + 39 mm wide for push-button row. Inner slot 20×110 mm, 15.22 mm deep. Bottom spacing 25 mm, 2 mm, 3Ø holes at 35 mm centres.
Rear Module Panel (Hintere Einschübe) — Drawing (p.33)
Cross-section of rear panel bracket, 2 mm thick aluminium, 59 mm between uprights, 15 mm flanges each side. Total height 42 mm. Two brackets (1 Stück, 1 Stück). Two angle brackets shown for two height variants: 191.5 mm and 207.5 mm.
[condensed — remaining pages are dimensional workshop drawings]