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Tektronix 647
50 MHz scope
647A front view

Produced from 1963 to 1967

Manuals – Specifications – Links – Pictures

The Tektronix 647 is a 50 MHz oscilloscope with plug-ins for both vertical and horizontal deflection. It was introduced in late 1963, along with a minimal set of plug-ins, and replaced by the higher bandwidth 647A in 1967. Except for the CRT and the rectifiers in the HV power supply, the 647 is all solid state.

The original 647 project leader was Oz Svehaug in 1962. From 1963 onward, Oliver Dalton took over.

The intent was to offer a higher performance scope in a small form factor, roughly the size and weight of the 560 series. It was promoted as “ruggedized” with an extended operating temperature range, and higher shock and vibration ratings than previous lab grade instruments.

The 647 uses 10 series vertical and 11 series time base plug-ins. At introduction, the 10A2 a dual channel 50 MHz vertical, 11B1 single time base, and 11B2 dual time base were offered. The 10A1 45 MHz differential comparator was introduced in 1965, the 10A2A amplifier in 1967. The 10 and 11 series plug-ins are unique to the 647 and 647A.

Key Specifications

Bandwidth DC to 50 MHz with 10A2 plug-in, 45 MHz with 10A1 (35 MHz at <5 mV/div)
Rise time 5.8 ns with 10A2, 7.8 ns with 10A1 (10 ns at <5 mV/div)
CRT T6470, P31 std / P11 opt., 6 cm × 10 cm, 14 kV acceleration
Power 108/115/122/216/235/244 VAC ±10%,selected via primary voltage selector and voltage range selector switches, 50 Hz to 60 Hz; 185W with 10A2 & 11B2 plug-in
Operating Temperature –30 C° to +65 C°
Cooling AC Fan (only in rack variant)
Thermal Protection Automatic resetting thermal cutout, in case internal temperature exceeds safe operating level
Weight 18.4 kg (40.5 lbs)


Unlike the threaded knob used for retaining the 530/540 series plug-ins, the 647 uses a lever-actuated cam mechanism. The single lever both engages and disengages the plug-in with a quick, smooth motion. Many users considered it to be the best plug-in retaining system Tek had ever offered.

Unlike the 560 series where the plug-ins directly drive the CRT deflection plates, the 647 has amplifiers for both the vertical and horizontal signals in the mainframe. In addition to supporting the higher bandwidth, the amplifiers provide a normalized gain at the plug-in interface, eliminating the need to adjust the gain or sweep cal every time a plug-in was swapped.

The 647 has a 140 ns delay line between the vertical plug-in connector and the input of the vertical amplifier. The interface between the vertical plug-in and the mainframe is a 93 Ω controlled-impedance connection. This is in contrast to the 500-series scopes, which appear to the plug-in as a high impedance.

The horizontal and vertical plug-ins are not electrically interchangeable. Only a 10 series plug-in will work in the vertical compartment, and only a 11 series time base will work in the horizontal compartment. X-Y mode requires the use of the external horizontal input in an 11 series time base.

The 647 uses the T6470 CRT with electromagnetic trace rotation and 14 kV total accelerating voltage. The HV power supply contains five 5642 rectifier tubes: three for the +11.2 kV CRT anode supply, one for the -2.2 kV CRT cathode, and one for the -2.2 kV CRT grid/blanking.

The calibrator in the 647 is based on a 4 kHz crystal, which is divided down to 1 kHz ±1 Hz.

The solid extender for 647 plug-ins is the 013-077.






Some Parts Used in the 647

Part Part Number(s) Class Description Used in
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
T6470 154-0434-00 154-0448-00 CRT CRT 647 647A

Some Parts Used in the RM647