545

Manuals – Specifications – Links – Pictures

The Tektronix Type 545 is a 30 (33) MHz scope that takes letter-series and 1-series plug-ins. It has two timebases, which allows delayed triggering.

Type 545 was introduced February 7th, 1955 along with Type 541, and superseded in 1959 by Type 545A, which was in turn superseded in 1964 by Type 545B, which was produced until 1973. Type 543, which is a 541 with 100x sweep magnifier, was introduced in 1958.

The difference between the 545A and 545 is the control ergonomics, not any major circuit design changes. The main improvement was to replace a pair of switches for the time base (8-position Time/Div and 6-position multiplier) with a single 24-position switch, freeing up front panel space for a Time Base B Trigger Mode rotary switch. Additionally, the delaying timebase on the 545A supports delays up to 10 seconds while the 545 supports delays only up to 100 milliseconds.

The older 545 uses the T54 / 5BHP2 CRT, P2 phosphor was standard. The 545A uses the T5430 CRT for which also P2 phosphor was standard. The newer 545B came with the further improved T5470 CRT (also used in the 543B, 544, 546 and 547) and P31 phosphor as standard.

Versions

There were also rack-mount versions. Types RM41 and RM45 were introduced in October 1957, Types RM41A and RM45A were introduced in May 1959 simultaneously with their bench counterparts, and the rackmount Type RM545B or R545B was introduced at the same time as Type 545B.

Clones of the 545A are the Lavoie LA-265A and Hickok 1805A. These clones were not licensed by Tektronix.

Relationship of 545B to 547

Some feel that Type 547 replaced Type 545, but this is not quite true; Types 545B and 546/547 were introduced simultaneously (1964). It is more correct to say that the 50 MHz 546 and 547 were upgrades. (Type 544 is likewise the upgrade for 541/543.)

The Type 53K/54K plug-in was introduced with the 545 and 541, and until Type 53/54L came out in 1957, it was the only plug-in that could take full advantage of their bandwidth. There was never a full-speed dual-trace plug-in — that would wait until Types 1A1 and 1A2, which came out with the 545B.

Key Specifications

Bandwidth	30 MHz (33 MHz with a 50 MHz plug-in such as Type 1A1)
	— 545B —
Sweep	0.1 μs/div to 5 s/div, 1−2−5
CRT	T5470-31-2, 10 kV acceleration
Probes	2 P6006 probes with BNC connectors

please add

Internals

Early 545 units have selenium rectifiers. Later units have silicon rectifiers. A modification kit, 040-0395-00, converts a 545 from selenium rectifiers to silicon rectifiers.

The trigger circuit used a 6DJ8 tube in the 545 and 545A. NPN transistors are used in the 545B trigger circuit.

545 and 545A Vertical Path

Types 545 and 545A have a six stage differential distributed vertical amplifier made of twelve 6DK6 tubes. The vertical amplifier used in the 545A is also used in the 551 and 555. The 545 uses the 154-098 CRT. With the limited CRT technology available at the time, the higher bandwidth of the 541 and 545 came with a tradeoff. The vertical scale is only 4 divisions, 2 above and 2 below the graticule center line. The lower bandwidth 531/533/535 retained the 6 vertical divisions, as used in most other Tektronix scopes. Shorting the outputs of the vertical amplifier to ground can cause expensive damage by burning out the termination resistor network. Starting at Type 545A serial number 29960, there is a 150 mA fuse, F1054, to prevent that failure. This change was made available for instruments already built, in Modification Kit 040-227.

545B Vertical Path

Type 545B differs significantly from the 545 and 545A. It was designed by Dave Barton. It has a partly solid-state, non-distributed vertical amp, and uses the 154-0478-00 CRT which is also used in the 544, 546, and 547. Improvements in CRT design, including reduced deflection plate capacitance and increased sensitivity, increased the vertical scale in the 545B from 4 to 6 divisions. The improved CRT also uses a ceramic envelope, with a flat glass faceplate with internal graticule markings to eliminate parallax errors.

Links

• J.Evans' 545A page / 545B page
• radiomuseum.org: 545 / 545A / 545B
• Richard Sears: Tektronix 535A and 545A
• barrytech.com: 545 / 545A / 545B

Pictures

545

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  545, early style

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  545, early style

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  545, early style

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  545, early style

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  545, early style

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  545, early style

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  Distributed amplifier

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  545 in vertical rackmount form

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  545 with mod that adds silicon rectifiers in place of selenium rectifiers

545A

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  545A front

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  545A interior, right side

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  545A interior, left side

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  545A interior, right side detail (time base B chassis open)

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  545A interior, right side detail (time base A)

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  545A interior, right side detail (time base B)

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  545A interior, HV supply

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  545A interior, HV supply

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  545A interior, HV oscillator tube

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  545A interior, rectifier

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  545A interior, bottom view

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  545A interior, bottom view (DC voltage regulator section detail)

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  545A interior, bottom view (distributed amplifier section detail)

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  545A Delay line

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  545A block diagram

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  545A signal path

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  545A trace

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  545A handbook compartment

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  545A handbook compartment

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  545A on a Tek 202-1 cart

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  545A controls

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  545A trace

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  545A trace

RM45A

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  RM45A, standard color

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  RM45A rear

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  Brown-face RM45A

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  RM 45A with standard B timebase

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  RM 45A with raster B timebase, MOD 116B

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  RM45A from NASA

545B

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  545B front

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  a british made 545B (Tektronix Guernsey LTD. )

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  545B with Type M plug-in

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  545B right side

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  545B with 1A1

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  545B signal path

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  545B top

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  545B rear

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  545B right internal

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  545B vertical output stage

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  545B vertical output stage

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  545B Block Diagram

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  545B Power Supply

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  545B High Voltage Power Supply

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  545B Calibrator

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  545B Trigger A

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  545B Timebase A

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  545B Trigger B

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  545B Timebase B

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  545B Horizontal Amp

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  545B with 1S2

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  545B left internal

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  545B right internal

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  545B left external

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  545B right external

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  545B top external

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  545B Squarewave

RM545B

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  RM545B

Some Parts Used in the RM45

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Some Parts Used in the RM545B

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