Converting a TDC Selectron to 7p

[P3D E R Swanson <ers@xxxxxxxxxxxxxxxxxxxx>]

First, thanks to Steve Spicer and others who send info. I've written to
several people for more material, but when a carrier arrived the other day
I decided to just do it. I now have in front of me a 7p Selectron. The
actual modification isn't difficult, but retiming the mechanism is tricky.
The steps I used were:  1. dismantle the carrier 2. enlarge the sheet
metal apertures to 7p, working from left and right.  3. cut the shutter
working at the right only, and rivet on a piece of sheet brass to extend
the right side of the shutter. (when the shutter is in place, there's only
a millimeter or so left and right of overlap by the shutter over the outer
aperture-- it's slow careful work. You also need to notch the bottom left
so it repositions the shutter on the stop pin on the base track.  4.
extend the steel slide transport bar so it will engage the shutter lever
sooner (I drilled it out tapped it, and installed a hex screw).  5. Cut
away a bunch of the end cap so the shutter trip lever will clear (all done
from the inside so it doesn't show when you look at it. 6. Tap the
castings and replace the rivets with screws for easy disassembly (the two
screws on the end cap, inside, need to be filed flat for clearance).  7.
For timing the mechanism, I added a hex screw on the push lever, then
slowly filed away metal on the top slot until the slide stopped exactly
where I wanted.  8. After you get the slide placement to match the window,
THEN bend the shutter trip lever so it positions the shutter in the
correct position when open. At this point, test fit the end cap and grind
away material inside it until there is no impact on the operation of the
shutter plate. 

There's very little latitutde for error here because of the clearances of
the shutter in relation to the aperture, so go slow. Do lots of test
fitting and remove small amounts of metal at a time. This is an area that
gets hot, so don't use any glue-- everything needs to be metal work--
cutting, drilling, grinding, tapping, etc.

In a nutshell, that's about it. I used a Radio Shack metal  nibbler to
open the sheet metal, same as with the carrier in a Kodaslide.

I don't recommend doing this unless you have a spare carrier. This is a
project for a carrier with the traditional bent shutter plate lever that
you have to take apart anyway...

The sheet metal on the carrier I got to play with was bent a bit, and I
need to spend a little time truing it up to smooth out the operation, but
it's working like a champ as it stands...

Elliott



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