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. The A models have beam finder switches for each channel.

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1 MHz dual beam differential scope Tek 502 front Produced from 1958 to 1973 Manuals 502 Instruction (OCR PDF, 15M) 502A Instruction (PDF) (All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

Both beams have differential inputs. The horizontal deflection plates are common to both beams.

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.

Key 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	Type T60P2/T502P2/T5020P2 (P1, P7 or P11 were available as options); 502A: Type T5021; 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
2018 value	$7,070	$6,890	$8,560	$7,790

Internals

There is a transistor-regulated 6.2 V_DC heater supply for the tubes in the first stage differential amplifier. This heater supply uses the −150 V supply as its reference. The −150 V supply uses a 5651 voltage reference tube as its reference. There is no post-deflection acceleration. The CRT cathode voltage is −2900 V.

Mod 104 on a 502 provides single sweep lockout.

Later 502A have solid state (include nuvistor) input stage, a 6DJ8 as the deflection amplifier and transistors as amplifiers and cathode followers (only in the newest version).

The 502 uses a single supply for the upper beam and lower beam CRT cathodes. The 502A has separate supplies for the two CRT cathodes. This improvement in the 502A allows slight differences in horizontal CRT sensitivity between the two beams to be canceled out in step 8 of the calibration procedure.

Links

Tektronix 502A @ amplifier.cd (many internal pictures)

Pictures

502

502 front view
Image magnified from a flyer
502 left
502 right
502 bottom
502 trace
502 trace

502A

502A
502A right internal
502A right
502A left
502A rear
Solid-state input stage with two 6DJ*
502A vertical amp sn 25,997 to 30,999

RM502A

RM502A
RM502A rear
RM 502A
RM 502A display
RM 502A bottom
RM 502A transformer wiring
RM 502A top
RM 502A vibration-isolated vertical amp

Third version 502A, serial number greater than 31,000

top side lower beam input amp and attenuator, bottom side of upper beam vert input board
late model RM502A
late model RM502A
late model RM502A
late model RM502A
late model RM502A
late model RM502A
late model RM502A

Diagrams

502A block diagram
502A vertical amplifier
502 CRT circuit
502A CRT circuit
Cartoon in schematic: Mountain Climber