454

Manuals – Specifications – Links – Pictures

The Tektronix 454 is a 150 MHz portable dual-trace scope designed by Oliver Dalton and introduced in March 1967. It can be seen as an improved 453. The successor 454A was introduced in 1971.

The 454 is the fastest general-purpose Tektronix scope that does not use proprietary hybrid or integrated circuits. It uses a CRT with distributed vertical deflection plates.

Jim Williams wrote:

In about 1966 Carl Battjes figured out a way to use T-coil bandwidth boosting with transistors, which, of course, everyone knew was impossible. He applied T-coils to the 50 MHz 453, tripled the bandwidth, & begat the 454, which had an astonishing 150 MHz BW.

Key Specifications

Bandwidth	150 MHz (454: 100 MHz @ 10 mV/div, 60 MHz @ 5 mV/div; 454A: 100 MHz @ 5 mV/div, 50 MHz @ 2 mV/div)
Deflection	5 mV/div to 10 V/div; 1−2−5; 454A: additional 2 mV/div
Sweep	50 ns/div (454A: 20 ns/div) to 5 s/div (1−2−5) plus ×10 magnifier, and variable; timebase B to 50 ms/div
CRT	T4540, P31 phosphor standard / P11 optional; +12/–1.96 kV acceleration
Weight	13 kg / 29 lb
Power	90–136/180−272 V, 48−440 Hz, 100–145 W

It is possible to cascade the CH1/CH2 input amplifiers to obtain a sensitivity of 1 mV/Div (454A: 400 μV/div) at a bandwidth of 33 MHz.

The 454 has two ±12 V probe power outputs for P6045 probes.

Links

Documents Referencing 454

Document	Class	Title	Authors	Year	Links
Service Scope 43 Apr 1967.pdf	Article	New From Tektronix, Inc. In 1967		1967	568 • 230 • 454 • 647A • C-40 • 1A4 • 1A5 • 3L5 • 200-1
Service Scope 49 Apr 1968.pdf	Article	Quick Check for Tunnel Diodes	Tony Bryan	1968	Tunnel diodes • 454
Service Scope 49 Apr 1968.pdf	Article	Developing a Writing Speed Specification		1968	454 • C-31
Service Scope 51 Aug 1968.pdf	Article	Plug-on Versatility	Cal Hongel	1968	323 • P6048 • P6035 • 454

Documents Referencing 454A

Document	Class	Title	Authors	Year	Links
Tekscope 1971 V3 N2.pdf	Article	New Portables		1971	324 • 453A • 454A
Tekscope 1971 V3 N3 May 1971.pdf	Article	The New Portables		1971	453A • 454A

Patents that may apply to 454

References

Internals

The 454 has a 140 ns delay line in the signal path after the input channel switching and before the main vertical amplifier. There is a phase equalizer after the delay line to mitigate the harm done to pulse fidelity by the delay line.

To avoid the need for an additional 6 V heater supply for the six nuvistors built into the 454, the two existing +12 V and -12 V rails are used for this purpose to supply 8393 Nuvistors with a 13.5 V nominal heater voltage.

The vertical preamplifier, the attenuators, vertical display switching and positioning circuitry is mounted to a common subassembly with the vertical preamplifier PCA. Thus, servicing any part of the vertical input section requires extensive removal and desoldering of connections. Some of them are not mentioned in the manual.

- Near the right hand probe power connector it is required to desolder two chokes and a braid shield cable form stands on the main chassis, leading to the attenuator subassembly.

- The rear wire harness is partly soldered to the vertical display switch, and needs to be desoldered for complete removal of the vertical amplifier PCA.

- The metal sheets tongue around the "invert" pull switch may collide with a grounding lug on the middle sheet of the main chassis. Bending the lug away clears enough space to retract the PCA for removal.

Known issues

As mentioned by Mark Vincent in TekScopes forum, the 454, 453 and their A versions have several resistors with underrated wattage. This may lead to bias and supply issues.

One example is a nonfunctional delay sweep in a 454 with the delay pickoff pulse not passing the amplifier stage of Q965/Q975. This was caused by R1257 in 12 V decoupling network 1 being 10% high in value. The found symptoms were a static voltage of 2.1V at the emitters of Q965, Q975 and about -8.5V on TP970.

454 Modifications

The 454 came in several different modifications that were indicated on the field on the front plate directly below the "454" lettering, left of the serial number field. Known modifications are

• MOD163D
• MOD210N - P6047 accessory probes come in 6 ft variant with extra accessories.

It is possible to retrofit the more difficult to obtain 8393 with more common 7586 Nuvistors with the use of a 47 Ω, 2 W dropper resistor for the heater, since the only difference is the higher heater voltage of the 8393. The 47 Ω resistor will result in a similar 10% underheating (5.7 V of 6.3 V) for the 7586 as it is for the 8393 with the ±12 V Supplies in the 454. This was successfully tested with a 7586 in the B trigger CF and works without further modifications of the circuit except from the dropper resistor.

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  7586 used as B sweep trigger CF

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  47 Ω dropper resistor for the 7586 heater.

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  Output of the 7586 at TP836

It shall be mentioned that a complete retrofit has to be tested to not overload the ±12 V supplies.

Pictures

454

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  454 with traces

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  'A' intensified during 'B' mode

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  454 with P11-CRT

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  454 Voltage Regulator PCA

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  454 Vertical Amplifier component side.

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  454 Vertical Amplifier soldering side with vertical sensitivity switching.

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  454 Vertical Output Amplifier

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  454 Trigger preamplifier, A Sweep trigger and generator PCA

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  454 B Sweep delay pickoff, trigger and generator as well as horizontal amplifier PCA

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  454 Z axis amplifier PCA

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  454 Calibrator PCA

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  454 CRT distributed deflection assembly.

454A

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  454A Front

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  454A Bottom

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  454A Vertical amp

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  454A Top

Some Parts Used in the 454

Some Parts Used in the 454A