7904

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500 MHz non-storage mainframe Tektronix 7904 Produced from 1972 to 1992 Manuals Tektronix 7904 Manual (PDF) Tektronix 7904A Manual (DjVu) Tektronix 7904A Manual (Shannon Hill PDF with OCR) Tektronix 7904 Manual (Shannon Hill PDF with OCR) Servicing the 7904 High-Efficiency Power Supply (PDF) (All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

The 7904 is a 500 MHz mainframe with four bays. It accepts two 7000-series vertical plug-ins and two 7000-series horizontal plug-ins. It was introduced in late 1971/early 1972 (Note 1). The successor model 7904A was introduced in 1974. There is also a rack-mount version, the R7903, albeit with only one horizontal bay.

The 7904 makes extensive use of custom integrated circuits and hybrid circuits. The signal path is completely differential and all of the internal wiring is 50 Ω coax. The CRT has distributed vertical deflection plates.

Performance is largely determined by the plug-ins. The 7A19 vertical amplifier and 7B92 time base were introduced along with the 7904 to match the 500 MHz system bandwidth. A special plug-in requiring modifications to the mainframe, the 7A21N, provides direct access to the deflection plates up to 1 GHz at a sensitivity of 4 V/Div.

The 7904 has a many modes of operation. One mode is called "Independent-Pairs Display" in the manual, where the input to the left vertical plug-in is displayed using the B horizontal timebase plug-in, and the input to the right vertical plug-in is displayed using the A horizontal timebase plug-in. This resembles the trace-slaving "ALT" mode that is produced by an 1A4 in a 547. Many other modes are available. It is possible to put vertical plug-ins in the horizontal slots for X-Y operation. It is even possible to put a horizontal plug-in in one of the vertical slots to produce a raster scan.

The 7904 uses a switch-mode power supply and has no fan.

Specifications

Key Specifications

Bandwidth	500 MHz
Fastest calibrated sweep	500 ps/Div (with 7B92A)
Acceleration voltage	24 kV

Links

Notes

See 7A11 and John Addis, Good Engineering and Fast Vertical Amplifiers, in Jim Williams (Ed.), Analog Circuit Design: Art, Science and Personalities (1991), p.114, and Tektronix New Products 1972 brochure.

Pictures

7904 w Plugin
7904A
Plug-in interface board front
Plug-in interface board rear
7904 block diagram