BACKGROUND INFORMATION
THE EH-1000
After years of use and then storage once the analog Teletext television system was turned off yonks ago, I have finally gotten around to placing this professional, very well built equipment onto the workshop bench ... the "operation" has begun
This equipment was fully functioning but of no possible further use in our digital television (with no teletext broadcasts) era so now I have extracted components and modules "of interest" which can be used to restore another EH-1000 or think of this board as a "component farm" a place where some difficult (or impossible) spare parts may lurk ...
This PCB board module houses just one major item, but a very special one. It's an ELMA (Switzerland) full sealed multi-position rotary switch. In the EH-1000 this serves provides the Function control (lower edge, central to the front panel)
Now it's time to take out the "scalpel" and start the op!
One of the first things to note is that although this is branded Unaohm and manufactured in Italy, the components inside have been substantially sourced from European and English component manufacturers, the likes of Siemens and Philips in particular. This ELMA switch is readily identifiable, the company being well known in the electronics industry for their very high quality products, no sub-standard Asian product in the EH-1000!
THE DONOR EQUIPMENT
UNAOHM - Teletext Video RF Analyser
Model: EH-1000
Designed & manufactured in Milano, ITALY
Circa late 1980's (based on advertisements placed in Wireless World at the time and the date stamp on the AC transformer core)
Technology: Analog video broadcast signal analysis - specifically for examining lines of Teletext information "riding along" with the video signal
Luggable (heavy at 15kg) due to the heavy duty Aluminium outer case but more importantly, the inside welded steel frame chassis inside.
Well engineered inside, logically laid out using a number of modules which are well interconnected.
Designed for 220V 50Hz operation (because of this, we used this equipment via an AC variac many years ago)
Green emitting rectangular CRT based front panel display
Interested in the technical nitty gritty? Here is an old copy of the spec sheet
Enough of the yacker, let's "go out into the fields" and see what fruit this "component farm" could provide ...
FRONT PANEL CONTROL SWITCH MODULE
PCB type: double sided
Part #5262
One small board with just one major solitary component, the ELMA multi-position switch, the rest of the board has a matrix of small signal switching diodes.
Type: 08 Modular Switch Series
Part # 08-1110
Single Pole
Shorting (Make Before Break) type
Number of positions: 12 (Maximum) but the stop screw is fitted so that there are currently 8 working positions. This stop screw is easily accessible by the user (front, near the bearing) so the number of positions is user adjustable.
Fully sealed switch unit
PCB mount, contact outputs arranged in two rows
Contact material: 6 μm Silver
Steel shaft 4mm diameter with two flat sides (not a D shape)
Shaft length is 15mm
The PCB is supplied with the original L shaped mounting bracket, this can be easily removed.
Full technical and mechanical information is available HERE
Please keep in mind that the EH-1000 (and thus this board & switch) has been and was FULLY OPERATIONAL - you can be confident this switch will perform as designed.
Not interested in fitting into another EH-1000? Many high quality European designed and manufactured pieces of equipment use the ELMA range of switches, this could be just what is needed for your own service or restoration task.
PCB DIMENSIONS:
60mm x 35mm x 20mm height
WEIGHT: 75g
This 5262 module is now nice and safe within sealed bubblewrap, waiting to come to the rescue of another piece of equipment.
