549: Difference between revisions

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Tek 549 1a4 3.jpg
Tek 549 1a4 3.jpg
Tek 549 1a4 4.jpg
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Delayed_Trace.jpg|B INTEN BY A Trig in 549
549_Delayed_Trace.jpg|B INTEN BY A Trig in 549
Vertical_OP.jpg|8608 Vertical Output Tubes of 549
549_Vertical_OP.jpg|8608 Vertical Output Tubes of 549
Dual_Trace.jpg|Dual Trace in 549
549_Dual_Trace.jpg|Dual Trace in 549
Tubes_ON1.jpg|549 LV Power Supply Tubes  
549_Tubes_ON1.jpg|549 LV Power Supply Tubes  
Tubes_ON.jpg| 549 LV Power Supply Tubes
549_Tubes_ON.jpg| 549 LV Power Supply Tubes
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Revision as of 08:23, 12 February 2018

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30 MHz storage scope
Tektronix 549 front

Produced from 1966 to 1974

Manuals
Manuals – Specifications – Links – Pictures

The Tektronix 549 is the only storage scope that takes a letter-series or 1-series vertical plug-in.

It was introduced in 1966 and discontinued after 1973.

Key Specifications

Bandwidth DC to 30 MHz (at -3 dB Point), depending on vertical plug-in
Rise time 12 ns
Deflection Factor 100 mV/Div
Line Voltage 104/115/127/208/230 VAC ±10%,selected via primary voltage selector and voltage range selector Switches, 50 Hz to 60 Hz.
Thermal Protection Automatic resetting thermal cutout, in case internal temperature exceeds safe operating level
Power Consumption 650 W, 750 VA
Size 13W x 24L x 17H Inches or 43.2W x 32.9L x 60.7L cm
Weight 68 lb or 31Kg
Cooling AC Fan
Construction Aluminum alloy chassis. Anodized front panel. Blue vinyl coated cabinet

Internals

Mix of Transistors and Tubes

Like many Tek scopes from the period, the 549 uses a mix of transistors and tubes. For example, consider the buffer amplifier in the 549, whose purpose is to interface the high-impedance output of the plug-in with the low-impedance of the 200 ns delay line in the 549. As is usual in oscilloscope vertical circuits, the requirement is to have flat frequency response from DC to the maximum frequency of the scope and to have linear phase response over this same frequency range.

In the 549, this buffer is implemented as follows: A 6DJ8 tube configured as a cathode follower is used at the interface with the plug-in to present a high impedance to the plug-in. This input stage drives an NPN BJT differential amplifier, which operates at the bottom of a cascode configuration with a 7119 tube on top. The output of the cascode (the plate of the 7119) drives the delay line.

Since the entire signal path is differential, the common-mode voltage does not have to be zero, and it is not; the differential signal in the delay line rides on 167 volts of DC. After the delay line, the signal enters another cascoded differential amplifier with NPN BJTs on the bottom and 8608 tubes on the top.

The vertical deflection plates of the CRT are driven by the plates of an 8608 10-watt power pentode through inductive matching/peaking networks.

Non-Distributed Amplifier

The 549 is slightly unusual among 54x-series scopes in that it does not use a distributed vertical amplifier. (Other exceptions include the 545B and 547).

Triggering

Triggering is done using an NPN BJT Schmitt trigger.

Storage

The 549 uses the T5490 CRT.

The screen has two storage targets, upper and lower, whose storage mode and erase signals can be controlled independently. There is a remote control cable/switch, part number 012-0102-00 (photo below), that can erase the screen and reset the single sweep.

Links

Pictures