545
Type 545 is a 30MHz* scope that takes a letter-series or 1-series vertical plug-in. It has two timebases, which allows delayed triggering.
Type 545 was introduced in 1955 along with Type 541, and superseded in 1959 by Type 545A, which was in turn superseded in 1964 by Type 545B. Type 545A improved the control ergonomics significantly but did not embody any major 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. Type 545B has a partly solid-state, non-distributed vertical amp, and uses the same CRT as the 544, 546, and 547. The trigger circuit used a 6DJ8 tube in the original 545 and 545A, and NPN transistors in the 545B.
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. (Type 544 is likewise the upgrade for the 541.)
The Type 53K/54K plugin was introduced with the 545 and 541, and until Type 53/54L came out in 1957, it was the only plugin that could take full advantage of their bandwidth. There was never a full-speed dual-trace plugin - that would wait until Types 1A1 and 1A2, which came out with the 545B.
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 Type RM545B was introduced at the same time as Type 545B.
* 33MHz with a 50MHz plugin such as Type 1A1.
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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
