502
The Tektronix 502 is a dual-beam oscilloscope introduced in 1958, followed by the 502A in 1963. There is also a rack-mount model, the RM502A.
Both beams have differential inputs. The horizontal deflection plates are common to both beams.
Mod 104 on a 502 provides single sweep lockout. This feature is standard on the 502A, which also has beam finder switches for each channel.
A recessed switch in the left side panel allows the upper beam amplifier to be connected to the horizontal deflection plates for single-beam X-Y operation, providing a differential X input with the same sensitivity as the Y channel. The upper beam is positioned off screen in this mode.
If the combination of time base setting and magnification selector results in a sweep faster than 1 μs/div, the horizontal scale is not calibrated, and a lamp on the front panel lights up to remind the operator of that.
Key Specifications
Deflection | 100 μV/cm to 20 V/cm, 1−2−5, ±3% |
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Bandwidth | 1 MHz @ 200 mV/cm and above; 400 kHz @ 50 mV/cm, 200 kHz @ 5 mV/cm, 100 kHz @ 200 μV/cm |
CMRR | 502A: 40,000:1 @ 100 mV/cm and 1 kHz |
Input impedance | 1 MΩ // 47 pF |
Sweep | 1 μs/cm to 5 s/cm, 1−2−5, ±3%; magnifier ×2, ×5, ×10 or ×20 |
CRT | Early 502: Type T60P2/T502P2/T5020P2; Late 502, 502A: Type T5021P2; (P1, P7 or P11 were available as options) 10 vertical and 10 horizontal 1 cm divisions 3 kV acceleration |
Dimensions | 597 mm (23½") × 286 mm (11¼") × 381 mm (15") L×W×H |
Weight | 23.6 kg (52lb) |
Links
Documents Referencing 502
- (no results)
Documents Referencing 502A
Document | Class | Title | Authors | Year | Links |
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Service Scope 42 Feb 1967.pdf | Article | Simplify Waveform Measurements | 1967 | 502A |
- Tektronix 502A @ amplifier.cd (many internal pictures)
- Tektronix 502A internals @ youtube (German)
Prices
Year | 1959 | 1961 | 1963 (A) | 1971 (A) |
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Catalog price | $825 | $825 | $1,050 | $1,265 |
In 2023 Dollars | $8,700 | $8,500 | $10,500 | $9,600 |
Internals
The −150 V supply uses a 5651 voltage reference tube as its reference.
The 6.2 VDC heater supply for the tubes in the first stage differential amplifier is transistor-regulated. This heater supply uses the −150 V supply as its reference.
There is no post-deflection acceleration. The CRT cathode voltage is −2.9 kV.
The early 502 uses a single supply for the upper beam and lower beam CRT cathodes (HV transformer 120-114). Later models (1959+, see 070-090) and the 502A have separate supplies for the two CRT cathodes (HV transformer 120-150). This improvement allows slight differences in horizontal CRT sensitivity between the two beams to be cancelled out in step 8 of the calibration procedure.
Later 502A models have a solid state (plus nuvistor) input stage, a 6DJ8 as the deflection amplifier, and transistors as amplifiers and emitter followers (only in the newest version).
The 502 has a 123 °F (50.5 °C) thermal cutoff switch.
Pictures
502
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502 with (single-beam) X-Y display
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502 Mod.104 (single sweep), front
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502 Mod.104 (single sweep), front from lower left
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502 left interior
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502 right interior
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rubber shock mount of amplifier sub-chassis
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502 bottom
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502 trace
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502 trace
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502 front panel without knobs
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502 power supply section in operation
502A
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502A
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502A right internal
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502A right
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502A left
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502A rear
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Solid-state input stage with two 6DJ*
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502A vertical amp sn 25,997 to 30,999
RM502A
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RM502A
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RM502A rear
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RM 502A
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RM 502A display
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RM 502A bottom
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RM 502A transformer wiring
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RM 502A top
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RM 502A vibration-isolated vertical amp
Third version 502A, serial number ≥31,000
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top side lower beam input amp and attenuator, bottom side of upper beam vert input board
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late model RM502A
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late model RM502A
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late model RM502A
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late model RM502A
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late model RM502A
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late model RM502A
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late model RM502A
Diagrams
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502A block diagram
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502A vertical amplifier
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Early 502 CRT circuit, 120-114 transformer (secondary transformer pin numbers incorrect)
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Later 502 CRT circuit, 120-150 transformer
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502A CRT circuit, 120-150 transformer
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Cartoon in schematic: Mountain Climber
Applications
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Tek 502A in a Physiology lab
Components
Some Parts Used in the 502
Part | Part Number(s) | Class | Description | Used in |
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120-117 | 120-117 | Discrete component | power transformer | 502 |
12AT7 | 154-0039-00 | Vacuum Tube (Dual Triode) | dual high-gain triode | 161 • 180 • 310 • 310A • 315 • 316 • 360 • 502 • 502A • 511A • 512 • 513 • 513D • 514 • 514AD • 514D • 516 • 524 • 529 • RM529 • 544 • 546 • 547 • 556 • 565 • 570 • 3A2 • 75 • 3A75 • 1M1 • A • B • C • G • H • K • L • ML • M • N • K • R • S • Z • Keithley 610B |
12AU7 | 154-041 • 154-0041-00 • 154-0287-00 | Vacuum Tube (Dual Triode) | dual medium-μ triode | 104 • 104A • 122 • 160 • 161 • 162 • 181 • 190 • 310 • 310A • 316 • 317 • 3C66 • 502 • 502A • 507 • 511A • 512 • 516 • 517 • 517A • 524 • 526 • 535 • 536 • 545 • 545A • 545B • 547 • 549 • 555 • 561 • 564 • 570 • 575 • 581 • 581A • 585 • 585A • C • D • E • N • Q • Hickok 1825 |
12B4 | 154-044 • 154-0044-00 | Vacuum Tube (Triode) | power triode | 126 • 310 • 310A • 316 • 317 • 502 • 502A • 524 • 526 • 541 • 541A • 535 • 535A • 545 • 545A • 546 • 547 • 570 • 549 • 551 • 555 • 513 • 581 • 581A • 585 • 585A • Keithley 610 |
2N301 | 151-0001-00 | Discrete component | germanium PNP power transistor | 502 • 502A |
5642 | 154-0051-00 • 154-0079-00 | Vacuum Tube (Diode) | directly-heated high-voltage rectifier | 310 • 310A • 316 • 317 • 360 • 453 • 502 • 502A • 503 • 504 • 506 • 513 • 515 • 516 • 524 • 529 • RM529 • 533 • 533A • 535 • 536 • 543 • 543A • 543B • 545 • 545A • 545B • 547 • 551 • 555 • 556 • 560 • 561 • 561A • 561S • 564 • 567 • 570 • 575 • 581 • 581A • 585 • 585A • 647 • 647A |
5651 | 154-052 • 154-0052-00 • 154-0288-00 | Gas Discharge Tube (Voltage regulator) | 87 V voltage reference | 128 • 160 • 310 • 310A • 502 • 503 • 504 • 511A • 512 • 516 • 517 • 524 • 526 • 531 • 531A • 535 • 536 • 541 • 541A • 543 • 543A • 543B • 545 • 545A • 545B • 570 • 549 • 581 • 581A • 585 • 585A |
5AR4 | 154-0168-00 | Vacuum Tube (Dual Rectifier) | dual rectifier | 502 • 502A • 160 |
6AL5 | 154-016 • 154-0016-00 • 154-0038-00 | Vacuum Tube (Dual Diode) | high-perveance dual diode | 163 • 181 • 190 • 1M1 • 310 • 310A • 315 • 316 • 317 • 3B1 • 3B1S • 3B2 • 3B3 • 3B5 • 502 • 502A • 503 • 511 • 511A • 512 • 516 • 517 • 517A • 524 • 526 • 535 • 535A • 545 • 545A • 549 • 551 • 565 • 570 • 581 • 581A • 585 • 585A • C • T • Telequipment D52 • Telequipment D56 • Telequipment S52 |
6AN8 | 154-078 • 154-0078-00 | Vacuum Tube (Triode/Pentode) | triode-pentode combo | 310 • 310A • 316 • 317 • 360 • 502 • 502A • 516 • 517 • 517A • 526 • 565 • 570 • 575 • N |
6AU6 | 154-0022-00 • 157-0073-00 • 157-0059-00 • 154-0284-00 | Vacuum Tube (Pentode) | RF pentode | 107 • 160 • 181 • 190 • 60 • 2A60 • 72 • 3A72 • 3C66 • 310 • 310A • 316 • 317 • 360 • 502 • 502A • 506 • 511 • 511A • 512 • 513 • 516 • 517 • 517A • 524 • 526 • 529 • RM529 • 531 • 531A • 535 • 536 • 545 • 545A • 546 • 547 • 549 • 555 • 561 • 561A • 561S • 564 • 565 • 567 • 570 • 575 • 581 • 581A • 585 • 585A • 80 • C • CA • Q |
6BW4 | 154-0119-00 | Vacuum Tube (Dual Diode) | dual diode | 126 • 502 • 502A • 524 • 575 |
6CZ5 | 154-0167-00 | Vacuum Tube (Pentode) | power pentode | 317 • 502 • 506 • 526 • 555 • 561 • 561A • 561S • 564 • 565 • 567 |
6DJ8 | 154-0187-00 • 154-0305-00 | Vacuum Tube (Dual Triode) | dual triode | 111 • 132 • 161 • 310A • 316 • 317 • 502 • 502A • 503 • 504 • 506 • 515 • 516 • 519 • 526 • 529 • RM529 • 533 • 535 • 536 • 543 • 544 • 545 • 545A • 545B • 546 • 547 • 549 • 555 • 556 • 561A • 561S • 564 • 565 • 567 • 581 • 581A • 585 • 585A • 661 • 1A4 • 1S1 • 60 • 2A60 • 63 • 2A63 • 67 • 2B67 • 3A1 • 3A1S • 3A2 • 3A3 • 3A6 • 3A7 • 72 • 3A72 • 75 • 3A75 • 4S2 • 51 • 3B1 • 3B1S • 3B2 • 3B3 • 3B4 • 3M1 • 3S76 • 3T77 • 3T77A • 9A1 • 9A2 • 1121 • 80 • 81 • 82 • 86 • B • O • W • Z • Telequipment D56 • Telequipment S32A • Telequipment D52 • S-311 • Telequipment TD51 • Telequipment S52 • Telequipment S51 • Telequipment Type A • TU-4 |
8056 | 154-0417-00 | Vacuum Tube (Triode) | low-voltage Nuvistor triode | 422 • 502 • W • 1S1 • 3A7 • 3S3 • 3T4 • 5T3 • 10A1 |
T502 | 154-0144-00 • 154-144 • 154-0170-00 • 154-170 • 154-0172-00 • 154-172 • 154-0173-00 • 154-173 • 154-0269-00 • 154-269 • 154-0270-00 • 154-270 • 154-0271-00 • 154-271 • 154-0272-00 • 154-272 • 154-0273-00 • 154-273 • 154-0274-00 • 154-274 • 154-0275-00 • 154-275 • 154-0276-00 • 154-276 • 154-0348-00 | CRT | dual-beam CRT | 502 |