560-series scopes
560-series scopes include:
These scopes use 2-series or 3-series vertical plug-ins and 2-series or 3-series horizontal plug-ins.
560-series mainframes contain no amplifier stages, requiring the plug-ins to directly drive the CRT deflection plates. While promoted by Tek as having the advantage of “not limited by additional circuitry between the plug-in and the deflection plates”, this configuration has a significant disadvantage. Touching up the gain or sweep cal when swapping plug-ins in scopes with amplifiers in the mainframe can be skipped, as doing so only tunes the accuracy to a small amount of additional precision. But in the 560 series, this step is required to even get crude accuracy, as the raw deflection factor of the CRT has a relatively large range, and the mainframe has no circuitry to normalize it.
To maintain good phase match over a wide range of frequency, the mainframe does not contain a delay line in the vertical path. The faster vertical plug-ins contain the delay line, which limits the available volume for amplifier circuitry.