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 #9177
The PCB has absolutely no other markings or coding on either the component side or underside, just 9177.
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 smattering of nice WIMA box caps, a few Styrene's and two interesting looking round metal 15mm diameter RF transformer cans with 4 active pins on the underside plus 2 anchoring pins. These could be useful as a can into which you could put your own wound coils/former.
The quality multi-turn trimmers are all BOURNS 3296 series
TO92 transistors are genuine Motorola 2N390x types (a mix of 3904's & 3906's)
A couple of 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 (2). They are both dual gang, a value is stamped into metalwork on the topside and no other markings. The pot is completely sealed ... shame the manufacturer didn't identify their product though!
The integrated circuits are more likely of much more interest, these are ALL in sockets and readily removeable
MC74HC14
MC74HC14E (RCA)
CD4030BE (RCA)
MC74HC73 2x
MC14093
HEF4081
HEF4011 2x
MC74HC164
MC74HC192 3x (Presettable Synchronous BCD Decade Up/Down counter)
MC74HC4052
MC74HC688 (8-bit magnitude comparator)
MC74HC221 5x (Dual monostable multivibrator)
SN74HC08
SN74LS123
MM74HC00
MM74HC4066
74F109
TDA1180P (SGS) Horizontal processor circuit for B&W and Colour CRT monitors
26x tasty morsels here, nothing really startling but some of these may come in handy for someone.
The manufacturers are mixed but ALL are of "good heritage" i.e TI, PHILIPS, SGS & 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
PCB DIMENSIONS:
175mm x 125m
WEIGHT: 250g
This 9177 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.
