A discrete transistor counter made in England in the early 1960's.
This model uses film-projection displays. The display brightness is uneven across the digits because portions of the films have darkened with age.
(Advertisement: Wireless World, Dec 1961, page 22.)
The grey boxes in a row at the rear are decade counter modules.
Inside one of the decade counter modules. Point-to-point wiring, that's not a printed circuit board. Only 2 flip-flops are in view, the other side of the board is similarly populated with another two flip-flops.
The transistors (Mullard OC44 & similar) are the black cylinders with
yellow-green-blue spaghetti on the leads.
Inside one of the film-projection display digit modules. These displays are based on an analog meter movement with a piece of film attached in place of the usual needle. The numerals 0 to 9 are present on the film. As the meter movement is energised a different numeral rotates into place in a light beam supplied by a standard incandescent lamp.
The top of the incandescent lamp is visible underneath the curving white wire at
the bottom of the photo.
A portion of the armature coil of the meter movement is identifiable by the
red-orange enamel wire.
Closeup of the film area, with a little level manipulation of the photo to bring out
the numerals on the film.
The funnel-shaped object is the end of the lens assembly coming from the lamp.
|Serial Number: ||L8273|
|Year of Manufacture: ||1964 (Components stamped with Dec 1963, Aug 64).|
|Date of Receipt: ||1998 Apr|
|State upon Receipt: ||Non-functional. Some lamps burned out. Meter movement for MSD bad, note also has different FS rating. Good physical condition.|
|Date: ||1998 Apr|
|Procedure: ||Crystal oscillator not operating. Crystal is bad, corrosion on internal contacts to physical crystal.|
|Date: ||1998 Apr|
|Procedure: ||Some wiring for lamps replaced.|
|Date: ||2005 Apr 28|
|Procedure: ||Original crystal replaced.|
.. | Venner TSA 3336/2 | ..
Early Digital Test Equipment