545

The Tektronix Type 545 is a 30MHz* 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Type 545 was introduced February 7th, 1955 along with the Type 541, and superseded in 1959 by the Type 545A, which was in turn superseded in 1964 by the Type 545B. The difference between the 545A and 545 is the control ergonomics, not any major circuit design changes.

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.

The Type 545B differs significantly from the 545 and 545A. 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.

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

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

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.

Early 545 units have selenium rectifiers. Later units have silicon rectifiers.

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 Type RM545B was introduced at the same time as Type 545B.

* 33MHz with a 50MHz plug-in such as Type 1A1.

• Tektronix 545 Manual (PDF)
• Tektronix 545A Manual (PDF)
• Tektronix 545B Manual (PDF)

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  545B signal path

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  545A block diagram

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  545A signal path

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  RM545B

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  545B front

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  545B top

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  545B right internal

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  545B vertical output stage