The Tektronix Type 531 is a 10MHz oscilloscope that accepts letter-series and 1-series plug-ins. It is exactly like Type 535 except it does not have the Delayed Sweep (dual timebase) feature. The 531 and 535 were the first Tektronix scopes to accept plug-ins. It was introduced in March 1954 simultaneously with the Type 535, 531 with below S/N 7950 have DuMount 5BGP2 instead of Tektronix T533P2. and superseded in 1959 by the Type 531A, which has more convenient controls and a slightly faster (15MHz) vertical amplifier.
In serial numbers 101 to 7600, the 531's L-C delay line is before the vertical amplifier. In serial numbers 7601 and up, the 531's delay line is between the vertical amplifier and the CRT. What was the reason for this change?
There is also a rack-mount 531A, Type RM31A. The RM31A has a sliding chassis so that the scope can be serviced without removing it from a rack. The 532 is similar to the 531, but designed to be more reliable at the expense of slower risetime. The 541 is mostly the same as the 531, but has a distributed vertical amplifier and a different CRT.
- Tektronix 531/541 Manual (DjVu)
- Tektronix 531/541 Manual (PDF)
- Tektronix 531 Factory Calibration Procedure (PDF)
- Tektronix 531A Factory Calibration Procedure (PDF)