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Tektronix SC504
80 MHz dual-channel oscilloscope
Tektronix SC504

Produced from 1978 to 1993

Manuals – Specifications – Links – Pictures

The Tektronix SC504 is an 80 MHz dual-channel oscilloscope plug-in for the TM500 system.

Key Specifications

Bandwidth 80 MHz (derated to 70 MHz from 35 °C to 50 °C ambient), 10 Hz AC coupling cutoff
Rise time 4.4 ns (derated to 5.0 ns from 35 °C to 50 °C ambient)
Deflection 5 mV/Div to 10 V/Div, 1−2−5, and ×2.5 variable; max. input 250 V (DC coupled), 400 V (AC)
Sweep 50 ns/Div to 200 ms/Div, 1−2−5; variable ×2.5 (to at least 0.5 s/Div); ×10 magnifier
Trigger 0.4 div or 60 mV, DC to 30 MHz; 1.5 div or 150 mV, 30 MHz to 80 MHz; AC coupling >50 Hz; AC LF REJ >10 kHz; HF REJ <50 kHz
Input impedance 1 MΩ // 20 pF
Ext Trig Input 1 MΩ // 24 pF (750 kΩ // 28 pF when not selected), max. 250 V DC+peak AC)
CRT 8×10 divisions of 6.35 mm (0.25") each; 12 kV acceleration, P31 phoshor; 154-0730-05 tube
Calibrator 0.6 Vp-p @ 1 kHz
Power approx. 26 W operating, <1 W in standby
Features 1-or 2-channel (chop/alt), Add (1+2), Subtract (1-2), X-Y mode (2 MHz, <3° to 50 kHz), single sweep


Rear interface

The SC504 has dedicated rear interface signal inputs switchable from the front panel AC/DC/GND/Int DC coupling selectors. These are terminated in 50 Ω (max. 5 VRMS, 0.5 W).

Additionally, it provides a trigger input, Z-axis input (±5 V), delayed gate input (ECL), gate select input (ground for ext gate), intensify input (ECL), Ch1 trigger output (>50 mV/Div, 30 MHz), triggered gate output (ECL), holdoff output (ECL), ramp output (0−10 V), sweep reset input, ready light output, and +5 V.


A slide switch under the right side cover allows the variable sweep control to be used as a variable holdoff control instead.

The SC504 uses some custom Tek ICs, namely the 155-0124-00 preamplifier (U4345), 155-0109-01 trigger (U3238), and 155-0122-00 A-B logic (U3158). There are two passive input attenuator hybrids (HY1520, HY1420) and two 155-0161-00 attenuator/amplifier hybrids (HY1530, HY1430).

The power supply uses the pass transistors provided by the two mainframe slots that the SC504 covers. Those on the right slot provide ±20 V from the mainframe's ±33.5 V rails, those on the left slot make +5 V from the +11.5 V rail and −5 V from the rectified 17 VAC supply. Power is drawn from the right mainframe slot, the pass transistors are the only connections on the left slot.


Custom ICs used in the SC504

Page Model Part nos Description Designers Used in
155-0109-00 M120B 155-0109-00 155-0109-01 trigger Gary Vance 5B25N 5B31 5B40 5B42 5B44 5S14N 7B50A 7B53A 7B80 7B85 7B87 7B81P 7B90P 7S14 7612D SC502 SC503 SC504
155-0122-00 M132A 155-0122-00 sweep control Larry Gagliani 455 SC504
155-0124-00 M138 155-0124-00 horizontal preamplifier Bob Nordstrom 455 SC504 2230 2232 2336 2337
155-0161-00 H616 155-0161-00 attenuator and amplifier SC504