485: Difference between revisions
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A healthy Tek 485 CRT has been observed to have a filament current of 98 mA. | A healthy Tek 485 CRT has been observed to have a filament current of 98 mA. | ||
A broken Tek 485 CRT that lost its vacuum | A broken Tek 485 CRT that lost its vacuum was observed to have a filament current of 153 mA. | ||
==Specifications== | ==Specifications== | ||
Revision as of 11:29, 2 February 2018
The Tektronix 485 is a dual-trace, portable analog oscilloscope with a maximum bandwidth of 350 MHz. The impedance of the inputs can be set individually to 50 Ω or 1 MΩ. The scope achieves its maximum bandwidth when the inputs are in 50 Ω mode.
The 485 was introduced in March of 1972. It includes a switching power supply and uses custom integrated circuits for most of the gain blocks. Triggering uses tunnel diodes.
A distinguishing feature – at least in a portable oscilloscope of its period – is the Alternate Horizontal Mode. In this mode, the B timebase is shown in a separate full-width scan, as opposed to the more common Mixed Mode, where the B timebase is shown on the same line as the A timebase, after the delay time. At the same time, the section shown with the B timebase is shown highlighted in the A scan.
The 465, which was introduced after the 485, only received this feature in its "B" incarnation (465B).
A healthy Tek 485 CRT has been observed to have a filament current of 98 mA. A broken Tek 485 CRT that lost its vacuum was observed to have a filament current of 153 mA.
Specifications
please add
Links
- Tek 485 @ amplifier.cd
- 485 troubleshooting @ YouTube
