Tektronix 7854 Waveform Keyboard Rebuild

From the Tek Wiki:

The Tektronix 7854 Waveform Processing Oscilloscope, introduced in 1980, is a 400 MHz combined analog / digital mainframe in the 7000 series that takes two vertical and two horizontal 7000-series plug-ins. In addition to a conventional analog (real time) scope, it contains an equivalent-time sampling 10-bit digitizer and a programmable waveform processor with GPIB interface. The waveform processor can be programmed using a detachable calculator-style keyboard, using postfix operators (“reverse Polish notation” like HP calculators) that operate on entire waveforms, not just individual numbers.

Tek 7854 Mainframe #2 after cleaning

Tek 7854 Mainframe after cleaning

It is to the repair of the detachable keyboard that this post is devoted.  I purchased a keyboard for a reasonable price only to find that some keys were intermittent, and some did not work at all.

Opening up the keyboard showed … Read More »

Tektronix 556 Dual Beam Oscilloscope Testing: Vertical Bandwidth

I have been doing some basic testing of my Tektronix 556 Dual Beam Oscilloscope, and I have documented some parts of this process.  I have also captured images of the traces, which I will share here.

Test Setup: Tektronix 556, 1A2 plug-in, Timebase A, Tektronix SG 503 Generator, and Tektronix TG 501 Time Mark Generator

I found the -3db vertical bandwidth of the 1a2/556 to be 65 Mhz, which is to be expected for the 50 Mhz rated 1A2.

TM 500 Module with Plug ins

TM 500 Module

50 kHz Reference Signal 6v peak to peak

Tek 556 with 1A2 Vertical 50 KHz BW Test

5 MHz Sine Wave 6v peak to peak

Tek 556 with 1A2 Vertical 5 MHz BW Test

20 MHz Sine Wave 6v peak to peak

Tek 556 with 1A2 Vertical 20 … Read More »

Tektronix 556 Dual Beam Oscilloscope

I had recently the unique opportunity to acquire a complete Tektronix 556 Oscilloscope setup.  This comprised the oscilloscope itself, the matching scope cart, original manual, probes and 12 plug-in units.  This in itself is rare enough, but in addition, this particular scope has the optically desirable blue phosphor CRT and Tektronix C-27 Camera Bezel.   This 50 MHz bandwidth oscilloscope was the state of the art when it was introduced in the mid 1960’s: Tekwiki Tek 556

This will be the first of many posts and updates as I work my way through checking and restoring this beautiful scope.

And now some images:

Tektronix 556 Oscilloscope

Tektronix 556 Oscilloscope

Tektronix 556 Oscilloscope

Tektronix 556 Oscilloscope

Tektronix 556 Oscilloscope

Thanks!

Shaun Merrigan

Tektronix Oscilloscopes 7904, 2467B, 2465B at 1GHz

The images to follow show a 1 GHz sine wave (amplitude not changed during the testing) on the following Tektronix oscilloscopes:

Tektronix 7904 with 7A24 vertical (400 MHz) and 7B92A horizontal

Tektronix 2467B (400 MHz scope)

Tektronix 2465B (400 MHz scope)

1 GHz Sine wave input on a Tektronix 7904 with a 7A24 vertical module

500 MHz Sine wave input on a Tektronix 2467B

1 GHz Sine wave input on a Tektronix 2467B

1 GHz Sine wave input on a Tektronix 2465B

1 GHz Sine wave input on a Tektronix 2465B

I have checked the bandwidth of the both the 2465B and 2467B used here, and they meet the 400MHz requirement at -3db (using a Tektronix SG504 with leveling head).  The bandwidth of the 7904 mainframe + 7A24 vertical plug-in used in this … Read More »