475
The Tektronix 475 is a portable dual-trace oscilloscope with dual time-bases similar to the 465, but with 200 MHz bandwidth and a maximum vertical sensitivity of 2 mV/Div. It is all solid-state except for the CRT. It was introduced in November 1972.
The military variant is called OS-261 C(v)1/0, which has a DC/DC converter (12/24V input) on board.
A revised version, the 475A (introduced in 1977), has 250 MHz bandwidth and a maximum vertical sensitivity of 5 mV/Div.
The 1106 is a battery pack for the 475.
The optional DM44 multimeter attaches to the top of the instrument.
From Tekscope Vol. 4 No. 5, 1972:
Electrical design team [...] for the 475 under the leadership of Jim Hinze was: Jim Godwin, Les Larson, Steve Tosh, and Jim Woo.
Key Specifications
| Bandwidth | 200 MHz (475), AC cutoff 10 Hz, switchable BW limit 20 MHz |
|---|---|
| Rise time | 1.75 ns (475) |
| Deflection | 2 mV/Div to 5 V/Div, 1−2−5 |
| Cascaded mode | 400 μV/Div, 50 MHz with CH1 input connected to CH2 VERT SIG OUT |
| Time base | 10 ns/Div to 500 ms/Div, 1−2−5, and ×10 magnifier |
| Input impedance | 1 MΩ // 20 pF |
| Triggering | 0.3 Div (int) or 50 mV (ext) to 40 MHz, increasing to 1.5 Div/250 mV at 200 MHz; AC coupling >60 Hz; LF REJ >50 kHz, HF REJ <50 kHz |
| X bandwidth | 3 MHz |
| Z axis input | 5 Vp-p, 50 MHz |
| Calibrator | 1 kHz, 30 mA / 300 mV square wave |
| Outputs | CH2 Vert Signal Out, 20 mV/Div into 1 MΩ or 10 mV/Div into 50 Ω; A and B +GATE OUT, +5 V; Probe power jack |
| CRT | 8 × 10 cm², P31 phosphor (P11 opt.), 154-0677-00 |
| Power | 110, 115, 120, 220, 230 or 240 VAC ±10%, 48-440 Hz, max. 100 W |
Internals
The 475 uses a number of Tek-made integrated circuits, including the 155-0032-01 input preamplifier, 155-0085-00 input amplifier, 155-0078-00 vertical amplifier, 155-0091-00 channel switch, 155-0082-00 vertical output amplifier, and 155-0049-00 sweep control.
Links
- Lazy Electrons Tektronix 475A & DM44 Repair Page
- The New Look in Portables, in Tekscope Vol. 4 No. 5, 1972
- Tek 475 / Tek 475A @ amplifier.cd
- Tek 475A / DM44 repair by vintageTek Museum @ YouTube
- Tek 475A in operation @ YouTube
- Tektronix 475A and DM44 Repair Power Supply and Logic by Zenwizard Studios @ YouTube
- Tektronix 475A and DM44 Power Supply and Tube Alignment @ Zenwizard Studios YouTube
- 151-0367-00 Guaranteed Bad Parts @ Zenwizard Studios YouTube
- Tektronix 475A Vertical Alignment and One Last Power Supply Issue @ Zenwizard Studios YouTube
- Tektronix 475A Trigger Section Alignment @ Zenwizard Studios YouTube
- Tektronix DM44 & 475A Horizontal Alignment by Zenwizard Studios @ YouTube
Common Problems
- See 475/Repairs
Pictures
-
Tektronix 475A
-
Tektronix 475A
-
Tek 475 in mixed sweep ("MIX") horizontal mode
-
475A with DM44
-
475
-
475 rear
-
475A with DM44
-
475
-
-
475A rear
-
475 (OS-261 C) rear, with DC-Input
-
475A A9 Interface board
-
475A A6 & Fan Motor
-
475A A7 Timing board
-
475A Power Supply Section of A9
-
475A with DM44 Board on top
-
475A A3 Vertical Preamp board
-
475/DM44 measuring a 1 kHz sine wave
-
475/DM44 measuring a 10 kHz sine wave
-
475/DM44 measuring a 100 kHz sine wave
475M
Custom ICs used in the 475