The Tektronix Type 543 (rack mount RM43) is an all-tube 30 MHz scope introduced in 1958. It takes letter-series and 1-series plug-ins. It is similar to a 545, but without the second, delayed timebase. Instead, it has a range of horizontal magnifiers from ×2 to ×100.
While the 545 has two non-calibrated X-input sensitivities, the 543 has an X input with calibrated deflection sensitivity of 0.1 V/cm, 1 V/cm, or 10 V/cm.
The 543B is a tube/transistor hybrid scope. The vertical amplifier has a 6DJ8 cathode follower stage followed by two transistor/tube cascode stages with a 186 Ω delay line in-between. The standard CRT for the 543B is part number 154-0478-00, also known as the T5470-31-2. There is a rackmount version, Type RM543B.
543B with CA