7844: Difference between revisions
(prices) |
|||
| Line 83: | Line 83: | ||
File:Tektronix 7844.JPG |Tektronix 7844 front view (with [[7A26]], [[7A19]](?), [[7B80]] and [[7B85]]) | File:Tektronix 7844.JPG |Tektronix 7844 front view (with [[7A26]], [[7A19]](?), [[7B80]] and [[7B85]]) | ||
File:Tektronix r7844.jpg |Tektronix R7844 | File:Tektronix r7844.jpg |Tektronix R7844 | ||
File:Wellenkino 7844.jpg | File:Wellenkino 7844.jpg | 7844 with options 78 (blue P11 phosphor) and 21 (dedicated vertical slots, i.e. no vertical mode switch) | ||
</gallery> | </gallery> | ||
Revision as of 12:12, 25 January 2015
The Tektronix 7844 is a 400 MHz dual-beam CRT oscilloscope that takes two 7000-series vertical plug-ins and two 7000-series horizontal plug-ins.
Versions include the 7844 bench-top lab scope and R7844 rack-mount model.
A typical configuration might have included 7A24 or 7A19 amplifiers, a 7B80 and a 7B85 timebase.
Key Specifications
| Bandwidth | 400 MHz (with 7A19, 7A29) eq. 0.9 ns rise time |
|---|---|
| Fastest calibrated sweep | 1 ns (with 7B80, 7B85) |
| Power | 90-132 V or 180-264 V, 48 to 440 Hz, max. 235 W |
| Weight | 16.3 kg (36 lbs) / R7844: 15 kg (33 lbs) |
Internals
The 7844's CRT has distributed vertical deflection plates.
The power supply is a resonant switch-mode inverter with linear post-regulation, similar to the one in the 7904. Despite this, the 7844 is fairly heavy, which is mostly due to the second vertical delay line. The delay lines need extra space and are located vertically to the right of the CRT instead of below the CRT as in other 7xx4s.
Unlike other 7000 series mainframes with switch mode PSUs, the 7844 does have a fan.
The 7844 is more complex than all other 7000 mainframes because vertical and horizontal amplifiers as well as the Z axis control boards exist twice, and there is an extra switching logic board.
Links
- Tek 7844 page at amplifier.cd and a repair report (switch-mode PSU)
- Tek 7844 @ barrytech.com
- R7844 page with frequency response measurements
Prices
| Year | 1976 | 1980 | 1984 | 1990 (7844R) | |
|---|---|---|---|---|---|
| Mainframe only | Catalog price | $6,100 | $9,125 | $13,435 | $19,500 |
| 2014 value | $25,320 | $26,150 | $30,540 | $35,230 | |
| Mainframe with 2 × 7A19, 7B85, 7B80 |
Catalog price | $9,500 | $14,275 | $21,520 | $30,660 |
| 2014 value | $39,430 | $40,910 | $48,910 | $55,400 |
Pictures
-
Tektronix 7844 front view
-
Tektronix 7844 rear view
-
-
-
Tektronix R7844
-
7844 with options 78 (blue P11 phosphor) and 21 (dedicated vertical slots, i.e. no vertical mode switch)
Interior
-
Right interior. Top row: Calibrator board (l), readout board (c), beam 2 horizontal amplifier (r), fan.
-
Right/above interior. The dual delay lines can be seen behind the readout board. Horizontally mounted bards in the center are: Crossover mode switch (l), trigger selector (c), power supply (r).
-
Beam 2 vertical amplifier, CRT and termination detail (right side)
-
Left interior. Beam 1 vertical amplifier (l), crossover vertical interface (r).
-
Left/above interior. Top row: Beam 1 Z axis (l), Beam 1 / Beam 2 horizontal amplifiers (c/r).
