Artifacts found in the shop.

Much of the material that was moved out of the shop in haste is now being sorted.  No explanation is being offered for this image.....



Shop is Operational

One of the final steps in making the shop operational was the replacement of the original 1961 bench tops with new maple bench tops.  The original bench tops were made from discarded wood.  In this picture the walls of the shop see daylight for the first time since the shop was built.

Next, it was necessary to construct new level bases for the maple tops.  All of the support lumber was four by four redwood, making for a sturdy base.

Here is the completed results.  One bench is at a sitting height while the second bench works well when standing.  In the second photo you can see the original front door that I saved from the house when it was demolished.

Motorola Mystery

While trying to restore an older analog bench supply I discovered that the series pass transistor in all of the regulating circuits used a Motorola 1700G transistor.  The mystery is I can find no record of this device either on the Internet, or in the large collection of Motorola data books that I have.  The part is clearly marked with the famous Motorola logo and the number 1700G.  I’ve even gone so far as to dig through boxes of used books at OpAmp Labs Book Store. (http://opamp.com) By the way one of the best technical book stores in Los Angeles.

I was able to get a sense of what the device was from looking at the schematic and putting it on my Tek 575 curve tracer.  ( fixed up discard from a friend who found it at a ham-fest in Santa Barbara.)  Here is plot from the curve tracer that I labeled using Photoshop.

One of the handiest pieces of hardware that I have, other than the curve tracer, is an old scope camera that I modified by removing all of the Polaroid dependent parts from and replacing it with a shelf and baffle that accommodates a small digital camera. 

Here is a picture of the camera in use on a Tek 556 dual beam scope.

The good news is that all the series pass transistors appear to be good.  I am, however, still surprised that I can find no record of this device.  If anyone knows anything about this mystery device, let me know.

Shop Update

Some of this is a little delayed, but I finally had a chance to load a few pictures of the shop re-build into my lap top.  This picture shows the floor removed and the dirt being prepared to receive the rebar for the pylons and grade beams.

This view is looking out of the shop toward the door of the shop.  All of the iron work is in place and ready for the pouring of the concrete.

At last the new floor is in place.  The next step will be to remove the rotted wood in preparation of framing, and roofing.

Now the fun begins.  Here is the roof that I helped to build when I was 9 years old being removed.

Lab Clock Near Completion

A precision time source for the lab is up and running.  I'm using a surplus GPSDO (Global Positioning Satellite Disciplined Oscillator).  These units came out of cell sites and were used to keep the cell sites in step with each other.  The GPSDO is monitored by a surplus DL360 server picked up at a swap-meet for $40.

The server uploads the status to my web site so that I can monitor the GPSDO from a web address. The uploaded data shows the position of the satellites as well as the crystal aging.

The next step will be to put a distribution amplifier with built in divider chain.  This will take the 10 MHz from the GPSDO and feed it to multiple instruments.  I've built the distribution amplifier by modifying an old video distribution amp.  I replaced the 75 ohm build out resistors with 50 ohm resistors.  I also added a 50 ohm one to one transformer on each output so that I can eliminate ground loops when feeding multiple devices.  The divider chain gives me precision frequency outputs at 1 MHz, 100 KHz,

10 KHz, and 1 KHz.

The final piece of this project will be to derive 60 Hz from the 10 MHz master output. (Useful for monitoring the power grid, and driving conventional clock circuits.)  I plan to do this by extracting the third harmonic from the 100 KHz square wave, and then dividing the resultant 300 Khz signal down to 60 Hz.

Shop progress

The rebuilding of my Dad's shop is progressing nicely. The shop was originally built in 1961, and had a dirt floor. Here is how the shop appeared in the 70s. It's remained pretty much unchanged until recently. This picture is featured in the book about my Dad and uncle "The Legendary Lydecker Brothers".

Here it is being lifted off of the foundation so that the plywood floor and dirt can be removed and replaced by concrete.

Clock Wiget for the blog

After finding my way around setting up the blog I felt inspired to create my own wiget in the form of a Nixie clock.  I used this HP 5512A Electronic Counter as the model for my clock.

I found the counter in the junk yard at Apex electronics for $20.00 (http://www.apexelectronic.com) .  For anyone who lives in the San Fernando Valley, Apex is geek heaven.  After cleaning, fixing and painting I used pictures of the counter to create the images that I then animated using Java script, CSS, and HTML.  I seems to render on everything but Microsoft IE, so this is still a work in progress.