502

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Tektronix 502
1 MHz dual beam differential scope
Tek 502 front (with Single Sweep Mod 104)

Produced from 1958 to 1973

Manuals
Manuals – Specifications – Links – Pictures

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.

Specifications

Deflection 100 μV/cm to 20 V/cm, 1−2−5, ±3%
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)

Prices

Year 1959 1961 1963 (A) 1971 (A)
Catalog price $825 $825 $1,050 $1,265
2021 value $7,740 $7,530 $9,370 $8,530

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.

Links

Pictures

502

502A

RM502A

Third version 502A, serial number ≥31,000

Diagrams


Some Parts used in the 502

Page Class Description Used in
12AT7 Vacuum Tube (Double Triode) dual high-gain triode 180 315 360 502 502A 513 513D 514 514AD 514D 524D 529 RM529 544 546 547 556 M G K C A 3A2 1M1
12AU7 Vacuum Tube (Double Triode) twin medium-μ triode 122 181 502 502A 512 535 545 545A 545B 547 549 555 575 581 581A 585 585A C D
12B4 Vacuum Tube (Triode) power triode 126 502 502A 541 541A 535 535A 545 545A 546 547 549 551 555 513 581 581A 585 585A
5642 Vacuum Tube (Diode) directly-heated high-voltage rectifier 360 453 502 502A 504 506 513 515 516 533 533A 535 543 543A 543B 545 545A 545B 547 551 555 556 567 575 581 581A 585 585A 647
5AR4 Vacuum Tube (Dual Rectifier) dual rectifier 502 502A
6AL5 Vacuum Tube (Double Diode) high-perveance dual diode 181 316 317 502 502A 511 511A 516 535 535A 545 545A 549 581 581A 585 585A 551 Telequipment S52
6AN8 Vacuum Tube (Triode/Pentode) triode-pentode combo 360 502 502A 517 575
6AU6 Vacuum Tube (Pentode) RF pentode 107 181 310 502 502A 512 513 531 531A 535 545 545A 546 547 549 555 575 581 581A 585 585A C CA
6BW4 Vacuum Tube (Dual Diode) dual diode 126 502 502A 575
6CZ5 Vacuum Tube (Pentode) power pentode 502 555 561 561A 561S 564 567
6DJ8 Vacuum Tube (Double Triode) dual triode 132 502 502A 503 504 515 516 519 533 535 543 544 545 545A 545B 546 547 549 555 556 565 581 581A 585 585A 661 2A60 2A63 3A8 1121 1A4 67 81 82 86 3B1 3B4 O Telequipment S32A Telequipment D52 Telequipment S52 Telequipment S51 Telequipment Type A
8056 Vacuum Tube (Triode) low-voltage Nuvistor triode 422 502 W 1S1 3A7 3S3 3T4 5T3 10A1
T502 CRT dual-beam CRT 502


Some Parts used in the 502A

Page Class Description Used in
12AT7 Vacuum Tube (Double Triode) dual high-gain triode 180 315 360 502 502A 513 513D 514 514AD 514D 524D 529 RM529 544 546 547 556 M G K C A 3A2 1M1
12AU7 Vacuum Tube (Double Triode) twin medium-μ triode 122 181 502 502A 512 535 545 545A 545B 547 549 555 575 581 581A 585 585A C D
12B4 Vacuum Tube (Triode) power triode 126 502 502A 541 541A 535 535A 545 545A 546 547 549 551 555 513 581 581A 585 585A
5642 Vacuum Tube (Diode) directly-heated high-voltage rectifier 360 453 502 502A 504 506 513 515 516 533 533A 535 543 543A 543B 545 545A 545B 547 551 555 556 567 575 581 581A 585 585A 647
5AR4 Vacuum Tube (Dual Rectifier) dual rectifier 502 502A
6AL5 Vacuum Tube (Double Diode) high-perveance dual diode 181 316 317 502 502A 511 511A 516 535 535A 545 545A 549 581 581A 585 585A 551 Telequipment S52
6AN8 Vacuum Tube (Triode/Pentode) triode-pentode combo 360 502 502A 517 575
6AU6 Vacuum Tube (Pentode) RF pentode 107 181 310 502 502A 512 513 531 531A 535 545 545A 546 547 549 555 575 581 581A 585 585A C CA
6BW4 Vacuum Tube (Dual Diode) dual diode 126 502 502A 575
6DJ8 Vacuum Tube (Double Triode) dual triode 132 502 502A 503 504 515 516 519 533 535 543 544 545 545A 545B 546 547 549 555 556 565 581 581A 585 585A 661 2A60 2A63 3A8 1121 1A4 67 81 82 86 3B1 3B4 O Telequipment S32A Telequipment D52 Telequipment S52 Telequipment S51 Telequipment Type A
6DT5 Vacuum Tube (Pentode) power pentode 502A
T5021 CRT dual-beam CRT 502A