Building Eric’s Mk-VII

The 25th of February 2019 I started the build of a Mk-VII Paraset, the wooden case model and a power supply, also in a wooden case, like in this photograph:

Gathering parts, in my case, is today not such a problem, as I can pick freely from the Paraset Warehouse. I agreed with Eric to make the outside of the Paraset looking more or less authentic, but use modern parts “under the hood”.

First thing to do was to countersink the water-jet cut holes in the factory made front panel:


As you see, I clearly marked the holes that were NOT to be centered.

Next thing to do is to clear up the workbench in the garage, to make room for the spray-painting job. I will be preparing 3 front panels at the same time, to have a few painted panels on the shelf.

April 18, 2019. Finally! Temperature and moisture level in my garage are finally acceptable to spray paint the three panels I drilled earlier. They all got 3 coats of flat grey paint. I will leave them rest for a few days so the 2 component paint can harden.

Next thing to do is to put on the lettering. Or making the needed mechanical parts in the meantime. Phew! A lot to do, but great fun!

April 2, 2019. Some weeks ago I started the build of a new jig for modifying trimmer variable air capacitors into variable air capacitors with a shaft. The latter types are almost unable to find anymore. I had made a wooden jig before and that worked also, but had a few issues. So I made this:

To be able to see the adjusting of the vanes properly, I mounted an affordable digital microscope, that I can also use for other jobs that need magnification.

Next step is to take 3 varcaps apart and to cut off the extended bearing:

To the left, the original varcap without the blocking nut. In the middle the one with the cut off bearing. To the right the rotor and pressure spring.

Than, the varcap and its new shaft go in the jig and the vanes are adjusted. Than a hole through and through is drilled to receive the blocking pin, a 1,2 mm brass nail that is riveted. Below, the varcap in the jig. On the bottom you see the image of the vanes on the microscope screen.

And finally, after a while, you end up with the 3 variable air capacitors: