502

Image magnified out from a flyer

The 502 is a dual-beam oscilloscope introduced in 1958, followed by the 502A in the early 1960's. Both beams have differential inputs. When set for maximum sensitivity, the 502A is 100 microvolts/cm and has a vertical bandwidth of 50 kHz. At lower sensitivity settings the bandwidth increases. At 200 mV/cm the bandwidth is 1MHz. At 100 mV/cm and 1 kHz, the common-mode rejection ratio of the 502A is 40,000:1.

There is a transistor-regulated 6.2V 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 -2900V.

There is a 502, a 502A, and a rack-mount model, the RM502A. The price of the 502 in July 1959 was $825.

Mod 104 on a 502 provides single sweep lockout.

Later 502A have solid state (include nuvistor) input stage. 6DJ8 as deflection-amplifier and transistor as amplifier and cathode follower ( only by latest 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 allows slight differences in horizontal CRT sensitivity between the two beams to be canceled out in step 8 of the calibration procedure.

• Tektronix 502 Manual (PDF)
• Tektronix 502A Manual (PDF)

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  502 front view

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  502A block diagram

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  502A vertical amplifier

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  502 CRT circuit

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  502A CRT circuit

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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

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  502 left

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  502 right

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  502 bottom

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  Solid State Inputstage with two 6DJ*

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  502A