QRP Labs
Ray Whitcombe's nixie clock PDF Print E-mail
Written by Hans Summers   
Saturday, 28 February 2009 22:29

Ray writes:

"I had just 'resurrected' my original home brew digital timer/clock from the early 1970's. I made this to help in tape recording radio programs, (remember tape?) and now, as  I'm in the process of digitising and cataloging  these 'early' recordings, the clock also got dug up and refurbished.

"I attach photos of the 'beast' as it was, and the internals during the refurb. The only modifications made were the replacement of most of the original 74 series TTL for 74LS TTL + fitting dil sockets.- mainly to reduce the 'Carbon Footprint'!!!! Well I do pay for the electric! All the PCB's were made on the 'Kitchen Table' as was the front panel, the wooden box was made by a friend.

"OK, I do have some 'rough' paperwork which seems to have about 98% of the circuitry. Its all hand written in a note book. I attach scans of it.
I constructed it whilst employed at the Bush/Murphy development labs. A small grope of us were 'inspired' by some published circuits of digital clocks, and I took it from there. It went nicely with my tape recording exploits!

"I attach another photo taken in the late 60's showing my  biggest? DIY project - and boost to my CV. A colour set based on original Mullard designs from the late 60's. On top left is a Thorens TD150 with a 'Crystal set' sat on top - the 'Cat's Whisker' etc. being replaced with a Germanium diode gave Medium wave reception. On the right is a Leak Stereo 70 with a stereo tuner on top, this tuner, like the TV, was also of my manufacture. (Had a lot to do with the 70' as well - well I did work at Leak!) The Big wooden box sitting on top of the 'chest' is my first recorder, you can see the front panel of the  Mullard type record/playback unit with a level meter above. The deck inside was a Collaro. All this 'equipment' still survives - except the TV and the recorder, just too big for "Married Life"!!!!!

"Yes, indeed it is. I wanted good accuracy so the tape recorder etc. would switch on exactly on 'cue' - the BBC were good on time keeping then! A glass crystal had the best stability, so I chose a 1 MHz AT cut? Even after being 'laid up' over 25 Years + the 'refurb' it was still on frequency without adjustment!"

Last Updated on Sunday, 22 November 2009 00:50
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