Re: Why do we do it?

ehsjr
 

Reed Dickinson wrote:
Upon graduating from college with a BSEE I was interviewed by Tektronix at the UNM campus in Albuquerque. My senior project was
the home made 545D that I started building in 1956. I loaded the 545D into my car and brought it to the interview. The two engineers
doing the interview were quite impressed with the instrument and I was offered a flight back to Beaverton the next day for additional
interviews.
All went well and I received a good job offer. Living in sunny Albuquerque is not quite like living in rainy Beaverton so I turned them down.
I often wonder if I did the right thing. Hindsight is so wonderful, it lets you see your mistakes very clearly.
Here are a few notes on the 545D.
I left the USAF in 1956 with a firm foundation in military electronics and accepted a position with IBM. I attended IBM computer schools
at Kingston NY and became very familiar with the Tektronix 541 Oscilloscope, a fantastic instrument at the time, strictly state of the art. I transferred to MIT�s Lincoln Labs in Bedford, Mass. At Lincoln Labs there was an electronics and metal shop where one could work on just
about any project. Since I had a love affair with a 541 and had the facilities to build one, I decided to do just that, build one. I laid
it out carefully building a cardboard model and decided to make it simpler by moving some of the circuits to different locations. I put
the horizontal generator across the front in the bottom. The power supply and regulator circuit went on the bottom in the rear as did the
power transformer. I was fortunate to get a scrap 531 that had been run over by a delivery truck and used a number of parts from it. The
vertical plug-in went on the right upper corner and the CRT on the upper left. The delay line ran down the right side of the vertical
amplifier, across the rear and up the left side to the CRT. I bought the vertical distribution coils from Tektronix and wound the 50
section delay line on a number of clear plastic dowels. I used fifty 1.5-7pF trimmers in the delay line. I drilled a series of holes a
long the rear to access the delay line trimmers. I built a 53/54C plug in unit from scratch and a 53/54K from another crushed unit. Work
was slow and before I had it powered up I was transferred back to Kingston NY as a bench technician in early 1958. I soldered the final
joint and then spent a month getting a beam on. I recall the period after I first obtained a beam. I could not turn the horizontal
oscillator off, it free ran. I finally traced it down to a heater to cathode short in a 6AL5! I built a mercury pulser driven be a 60 Hz
mercury wetted relay to adjust the delay line. I worked in the dark for over 3 weeks tweaking the delay line until it was perfectly flat. It was necessary to work in the dark as the trace from the 60 Hz pulser was so faint at the fast sweep speed necessary that it was almost un-readable.
About this time I realized that I was doing engineering work and getting technicians pay so I decided to return to Albuquerque, NM, and
attend UNM and earn a BSEE. I used the home made 541 as my senior project. I completed my BSEE in 1964 and started on a MSEE. Spare parts for the 545 were becoming readily available after 1964 and I obtained a delay board assembly, a high voltage assembly and a
delay line assembly. I installed the delay board assembly below the CRT as it fit nicely in that area. I changed all the necessary components
and switches and after several months was able to change the scope from a 541 to a 545. I also added a running time meter to a vacant space in the rear and decided to stamp 545D as the model number on the top above the CRT. I used this scope up to 2000 when I started to accumulate 465 to 485 scopes. I passed the 545D on to Stan Griffiths for his museum. I guess that it represented so much work over so long a period of time that I will always have a nostalgic feeling for that instrument.
Reed Dickinson
Thanks for that!

Write ups like yours (which was, in my best Tony The Tiger voice,
G R R E A T!) are one more reason we do it. How can we read
about what you did without drooling??!

Ed

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