485

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Tektronix 485
350 MHz portable scope
Tektronix 485

Produced from 1972 to 1986

Manuals
Manuals – Specifications – Links – Pictures

The Tektronix 485 is a dual-trace, portable analog oscilloscope with a maximum bandwidth of 350 MHz, introduced in March of 1972. The project leader for the horizontal section of the 485 was Murlan Kaufman.

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.

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.

The 465, which was introduced after the 485, only received this feature in its "B" incarnation (465B).

Variant 485-1 omits the "A EXT Trigger display", as does variant 485-2 which additionally only has 50 Ω inputs.

Specifications

Input Impedance 50 Ω / 1 MΩ // 20 pF
Rise time 1 ns (50 Ω) / 1.4 ns (1 MΩ)
Bandwidth 350 MHz (50 Ω) / 250 MHz (1 MΩ)
Deflection 5 mV/div to 5 V/div in 1−2−5 sequence, 2% accuracy
Time Base 1 ns/div to 0.5 s/div in 1−2−5 sequence
CRT 154-0652-00 and 154-0652-05, 21 kV acceleration, 8x10 divisions (0.8cm/div)
Weight 21.5 lb/9.3 kg
Power AC 90-136V/180-272V 48-440Hz, 60W @115V

Links

Internals

The 485 includes a switching power supply and uses custom integrated circuits for most of the gain blocks. Triggering uses tunnel diodes.

Pictures

External

Internals


Custom ICs used in the 485

Page Class Manufacturer Model Part nos Description Designers Used in
155-0011-00 Monolithic integrated circuit Tektronix M012 155-0011-00 clock and chop blanking Les Larson 485 4851 4852 7313 7403N 7504 7514 7603 7613 7623 7633 7704 7704A 7834 7844 7854 7904 7904A R7903 7912AD 7912HB 7934 7104
155-0012-00 Monolithic integrated circuit Tektronix M015 155-0012-00 Z Axis Logic Les Larson 485 4851 4852 7504 7514 7704 7704A 7834 7844 7854 7904 R7903 7904A 7934 7912AD 7912HB 7104
155-0049-00 Monolithic integrated circuit Tektronix M079G 155-0049-02 sweep control with lockout Bill DeVey 335 464 465 466 475 485 4851 4852 5B31 5B40 5B52 5B42 5B44 7B53A 7B80 7B85 7B87 7B92A 7B90P 7B10 7B15 SC502 7B42N
155-0064-00 Hybrid integrated circuit Tektronix H074A 155-0064-00 vertical output amplifier 7834 7854 7904 7903 7912AD 485 PG502
155-0067-02 Monolithic integrated circuit Tektronix M091B 155-0067-02 SMPS controller Joe Burger Gene Andrews 7704A 7834 7844 7854 7904 R7903 7904A 7912 7934 7104 308 485 P7001
155-0076-00 Monolithic integrated circuit Tektronix M94 155-0076-00 input protection and probe logic John Addis Wink Gross 485 7A29 7A29P 11A52 11A71 11A72 SCD1000
155-0078-00 Monolithic integrated circuit Tektronix M084 155-0078-xx 155-0273-00 155-0274-00 broadband vertical amplifier John Addis 475 485 7834 7844 7854 7904 R7903 7912AD 7912HB 7A16A 7A16P 7A24 7A26 7A42 067-0587-01 AM503 PG502 PG508 DC510