517

The Tektronix 517 is a 50MHz scope introduced in 1950 or 1951. The power supply is an external box, like the 507, 551 and 555. The 517 does not take plug-ins. There is also a 517A. The 517 closely resembles a scope that Tektronix developed under a contract for the US military during 1949 and 1950.

The external power supply and oscilloscope are connected by a removable cable with Jones plugs on both ends. Units with serial numbers 101-1739 use a 12-pin Jones connectors; after that it is a 16-pin Jones connector. The voltages on the 12-pin connector are:

Pin 1: +750V, regulated
Pin 2: +475V, regulated
Pin 3: +350V, unregulated
Pin 4: +225V, regulated
Pin 5: +150V, regulated
Pin 6: Ground
Pin 7: -250V, regulated
Pin 8: +180V, unregulated

The 517 makes extensive use of the distributed amplifier concept. The vertical signal path is as follows:

Gain Stage 1: single-ended, six sections, distributed, 6AK5 tubes
Gain Stage 2: single-ended, six sections, distributed, 6AK5 tubes
Gain Stage 3: single-ended, seven sections, distributed, 6AK5 tubes
Signal Delay: 51 feet of RG63U 125-ohm coaxial cable
Phase Splitter: single-ended in, differential out, three sections, distributed, 6CB6 tubes
Gain Stage 4: differential, six sections, distributed, 6CB6 tubes
Gain Stage 5: differential, twelve sections, distributed, 6CB6 tubes

The 517 uses 24kV of acceleration voltage on the CRT. This is generated by the Type 420 High Voltage Power Supply subsystem in the 517. It uses a 1.8kHz oscillator to produce the high voltage, unlike other Tek scopes which use HV oscillators in the ultrasonic range.

front
bottom internal
right internal
top internal
power supply internal
12-pin power connector