221: Difference between revisions
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Tek221_Int_05.jpeg | Tek 221 - CRT & power supply board | Tek221_Int_05.jpeg | Tek 221 - CRT & power supply board | ||
Tek221_Int_06.jpeg | Tek 221 - Power supply board | Tek221_Int_06.jpeg | Tek 221 - Power supply board | ||
Tek221_Int_10.jpeg | Tek 221 - Power supply board | |||
Tek221_Int_07.jpeg | Tek 221 - Amplifier board | Tek221_Int_07.jpeg | Tek 221 - Amplifier board | ||
Tek221_Int_08.jpeg | Battery pack (fused) | Tek221_Int_08.jpeg | Battery pack (fused) | ||
Revision as of 19:11, 3 March 2022
The Tektronix Type 221 is a miniature 5 MHz analog scope introduced in 1973.
Key Specifications
| Bandwidth | DC to 5 MHz |
|---|---|
| Input Impedance | 1 MΩ // 29 pF |
| Input Voltage | max. 600 V DC + Peak AC, or 600 Vp-p AC |
| Sweep Range | 200 ms to 1 μs, 17 steps |
| CRT | 154-0705-00, 6 Div (V) × 10 Div (H), 1 kV acceleration |
| Operating Time on Battery | 2-3 hours |
| Internal Battery | 10 rechargeable NiCd cells |
| Line Voltage | 90-250 VAC @ 48−62 Hz, or 80-250 VDC |
| Power Consumption | 5 W @ 250 V |
| Dimensions | (H/W/D) 3" × 5.25" × 9" (7.6 cm × 13.2 cm × 22.8 cm) |
| Weight | 3.5 lb (1.5 kg) |
Internals
The 221 has a switching power supply and built-in rechargeable batteries (which are a maintenance issue). It has a transformer-coupled trigger circuit which would seem to preclude DC level-based triggering. The trigger circuit uses a 1N3713 1 mA tunnel diode. The vertical output amplifier that drives the CRT plates is two opamps made from discrete transistors. One drives the top deflection plate, the other the bottom plate.
The power supply in the 221 uses three transformers.120-0876-00 (T633) in the line inverter, 120-0877-00/120-0946-00 (T623) in the base drive for the line inverter and 120-0875-00 (T701) in HV inverter.
The 221 contains one integrated circuit, a 741 opamp that creates a virtual ground, otherwise only discrete (including dual) transistors.
MOD 290A is a version of the 221 made for IBM, which adds a Single Sweep function, and a "Property of IBM" engraving.
Pictures
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Side
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Front
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Front
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Panel of 221
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Panel of 221
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Probe of 221
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221 with orginal bag
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221 on top of 565
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MOD 290A variant for IBM
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MOD 290A variant for IBM
Internals
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Tek 221 - Internals, rear
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Tek 221 - Internals, LHS
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Tek 221 - Internals, top
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Tek 221 - Front Panel A1/A2 board
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Tek 221 - CRT & power supply board
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Tek 221 - Power supply board
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Tek 221 - Power supply board
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Tek 221 - Amplifier board
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Battery pack (fused)
