BACKGROUND INFORMATION
PERSONAL
I tell this story because others may relate to this ...
As a youngster growing up in NZ during the 1960's I had a strong interest in all things electronics. I am an "Old Timer" now and I am talking about the days when I would ride my bicycle to and from school and pass by this funny little electronics shop. The shop was called ELEQUIP (I can still clearly remember that but not much else these days!) and it was run by this European guy with a big pipe hanging from his mouth, I think he was a Czech it was a bit tough understanding him sometimes! He only had World War II surplus gear in his "Aladdin's Cave", shelves shelves and more shelves of what was to me, weird and wonderful equipment from the British Armed Services (I seem to remember). I spent many many hours in that shop, looking at all this strange Khaki coloured equipment, he even let me open them up to take a look around inside and he would explain what some of the parts were, I was drooling! - I was young and had no money to actually buy much of that stuff. The real fun was "out the back" of his shop where he put all the "junk" he didn't want, lots of modules, old valves, transformers - all freebies.
It was this type of experience that kindled in me the urge for the "treasure hunt" - looking at lots and lots of electronic equipment and sometimes finding something very special.
Looking and working through this UNAOHM EH-1000 bought all those early childhood days flooding back ...
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 board used extensive plug & socket interconnects to the other PCB's in the EH-1000, but I do notice there have been some "solder side" mods made (components added) - I have no idea why, we certainly never modded this gear.
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.
Another aspect that surprised me a little is the extensive use of IC sockets for the integrated circuits on most of the PCB's, a potential source of trouble when it comes to reliability (especially since the sockets are double wipe but not machined) but great when the board is being used as a component farm - no fuss de-soldering useful components.
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 ...
SIGNAL PROCESSING MODULE
PCB type: double sided
Part #9179
The PCB has absolutely no other markings or coding on either the component side or underside (not even component placement or designations), just 9179.
Professionally made board using a fibreglass substrate but it looks to have been meticulously manually soldered. In fact the entire construction of the EH-1000 looks as though this equipment was manually constructed from start to finish - no automation.
This board has a very tantalising selection of IC's on board, ALL are in sockets and easy to remove (don't forget to take ESD safety precautions!)
Beside the active devices, there is a couple of nice WIMA box caps, just one Styrene and a couple of nice looking power resistors (only around 3W though)
Some interesting looking open track trimpots, marked as 3359 xxx and I suspect these could be Bourn product - interesting because the substrate looks to be ceramic.
TO92 transistors are genuine Motorola 2N390x types (a mix of 3904's & 3906's) & 2N5771's
Six of the GUNTHER 3573 1231 121 Reed relays
The above are all thru hole soldered in place
I cannot tell you much about the nice looking but UNIDENTIFIED square body panel mounted pots (3, one is completely sealed with the remaining two being open frame (22K each). ... shame that the manufacturer didn't identify their potentiometer's though!
The integrated circuits are more likely of much more interest, these are ALL in sockets and readily removeable
MM74HC123
SN74HC00
TL072 (TI)
TEA 2014 (Video Switching 8 DIL)
MC74HC4052 4x
74F10 (Fairchild)
9x tasty morsels here, nothing really startling with the exception of the TEA device, you don't see these often anymore!
The manufacturers are mixed but ALL are of "good heritage" i.e PHILIPS, TI, Fairchild & Motorola - the latter dominates.
NO devices from QC dubious "XI DONG GOLDEN RAINBOW" factories in Asia!
Please keep in mind that the system (and thus this board) has been and was FULLY OPERATIONAL - you can be confident these devices will perform as designed.
This PCB was FULLY FUNCTIONAL prior to removal from the equipment, meaning that if were looking to "bring back to life" another EH-1000, this complete module 9179 could come in very useful
PCB DIMENSIONS:
220mm x 120mm
WEIGHT: 260g
This 9179 PCB has now been "laid to rest" within bubble-wrap and is lying on a stiff cardboard backing, everything then within a sealed clear plastic packaging, ready for a trip to another workshop.
