Wow, that is a tiny little bugger! I agree, they look like filamentary digits. My first thought had been Panaplex, but the segments are too thin for that (and all the Panaplex displays I've seen thus far are vertically asymmetric - the middle horizontal segment has always been slightly above the equator of the display.
Cool looking little box. 
-Pat
That tiny little bugger is now mine !
Seller was able to give me more information about this mysterious "Syracuse Electronics France " manufacturer... it was a small company, very much French, based in a little village by the name of " Bourguébus " nearby Caen. They were taken over by another obscure company by the name of Syrelec, itself taken over by a much more well known company this time, still in business today : Crouzet. French comapany too, as far as I know.
Instrument is much older than I thought, like, a decade older than I thought ! According to the date on the shcematics, it was designed in decement 1973 / January 1974.
Yes I have the schematics.. believe or not, the seller has the original printed/paper documentation ! Of course not much of it, small old company and all that, so just a few pages, but enough to give full schematics and board views (a few boards in there). Attached below is one of the pages, showing the schematic of the instrument, or most of it I reckon. Power supply, LF and HF input, decade counters... it's a basic counter not a universal one, so there is not much in there of course.
I just love these old paper docs, and having docs for such an obscure old piece of gear, in itself, is quite something. So it really added up to the "value" of this thing, to my eye at least.
As we can see on the schematics, the OCXO is a reality despite the age and provenance of this thing..... but of course, it's a home made one, both the oscillator and the oven temperature regulation, so no part numter to goolge for specs... so no specs. I guess one day when I can afford a 10MHz reference and distribution box/amplifier to feed to all my instruments... I could have some fun trying to characterize the OCXO performance in this little counter...
Seller just sent me a couple extra pictures, attached below. He tests the counter. First pic tests the LF input, he is supplying a 9.5MHz signal from a cool old HP RF synthesizer. Second pic, a 250MHz signal on the HF input, to prove that the counter meets its specs (250MHz is specified on the schematic), and it does ! That early '70s little box does deliver !
But how sensitive is the input at that kind of frequency ? Looking more closely at the pic of the HP synth, it says " 0 " on the output amplitude display. Looks like it is set to display dBm. Don't have an RF synth but googling it, seem s0 dBm means 1mW. I assume it implies a 50ohm load (which we have here, HF input of the counter is 50ohms), so if I get my math right the signal must mean the voltage level is 220mV or something ? Don't know if that's RMS or peak, though...
Still 200mV at 250MHz for this modest counter is not that bad eh ? It's usable what do you think ? Sure a better counter would have an amplifier and be able to detect much smaller signal level that that. That said, maybe this counter can do better than 200mV... the seller never told me he was trying to test the limits here, maybe 0dBm is simply the default amplitude the instruments gives you when you power it up, who knows !
Plus, looking at the schematic for the HF input, although we don't see a DISCRETE amplifier... it uses the usual divide by 10 chip which maybe might contain an amplifier ? Who knows. Chip part number is obscure : " 95 H 90 ".... I guess it's hopeless trying to find a datasheet on this thing...
So if I want to test the sensitivity of the HF input, at max frequency / 250MHz.... first I need to acquire an RF synth !!
Can't afford one but....a generous friend some time ago gave me an old RF generator, don't know if it's a synth or not (has a digital display in any case) but at least it's an RF generator, goes up to 500 MHz. It's old but it's not a piece of crap, looks like quality stuff. A boat anchor of course. It's an Enertec/Schlumberger model 4795. I have not put it to service yet because my friend warned me that before I even take the risk to power it up, there are a trillion dipped tantalum caps to replace, and that it's going to be a major undertaking given the internal construction of the instrument. I believe him... and have not even the courage to even open it up to gauge the amount of work that it will represent...
So I guess it's time for me to put that heavy beast on the bench and start recapping it !
Can't afford an old HP synth so I guess it' s a small price to pay if I want to have an RF generator AT ALL....
Also, look at the schematic for the input stage of the LF input this time... see something odd ?? Yes... looks like there is a TUBE rectifier in there ?!
A tiny Nuvistor I guess, of course.
So I was sold... made him an offer.. 80 instead of 100. He accepted. Still expensive but such is the market here. 80 is much better than 100, so it's less painful for my wallet. Plus I just pocketed today 110 Euros in cash for fixing the electric fence motor and Asus tablet I talked about a few weeks back... so the counter is already paid for !
Guy shipped it today, can't wait to receive it, a nice cute little exotic/uncommon piece of TE in my collection !!!!
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