ICs? Who needs ICs for digital logic?
The divide-by-10 circuits in the 1965 Tek 184 use only 3 transistors. How do they do that? Having debugged mine, that's a rhetorical question!
Now I know TOO !
What a coincidence/timing, look what me just got !
Some old junk to please Tautech !
An old Nixie counter, and no IC in there either, here too they used discrete trannies everywhere to do all the counting decoding or anything really.
Lucky me, for a change I was able to find a service manual. A rare occurrence for all these old French instrumentation companies. A nice manual at that, 20+ pages, in good resolution, with all the info you would want. So I attached the schematic for the decade boards/Nixie drivers, just because I love you. 5 identical boards of course, because 5 Nixies in this thing. First / fastest two decade boards have an identical design and layout as the 3 slower ones, all they did was use different transistor models.
As we can see there are 18 transistors on each decade board. 8 transistors was enough for them to implement the 4 bit counter. A pair of 2 transistors for each bit.
Then for the BCD decoding and driving of the Nixie, it's combined apparently, they use only one transistor per digit, so 10 transistors.
Note how funky looking the transistor symbol is, never seen them drawn like this before !
Anyway this one popped up here right after I bought that tiny Minitron counter, I don't choose timing, things pop up when they do... just so happens to have two nice things in a row... probably means I won't see anything worthwhile for a year now !
So, it's an old Nixie counter, from 1965, made by " Rochar " , short lived small French company (quickly bought and killed by Schlumberger, like they did with ADRET and Enertec and god knows who else).
5 digits, good for 2.2MHz it says in the manual, can't even test that, my old sig gen only goes to 1MHz !
It's a full featured counter, a universal counter, not a basic minimalist frequency counter like the Minitron I just bought.
Heavy and oozes build quality when you look at it and play with it. Thick aluminium face plate, engraved. Weighs a lot more than its looks might suggest. 6+ kg IIRC.
Counter is in tip top shape ! Excellent cosmetic condition inside out, no rust and barely a speck of dust inside.
Bright work in good shape except as usual for the old silver plated BNC connectors of that era... silver tarnished nothing you can do about it... so will need replacing with more modern BNC.
All Nixies work perfectly, very bright and even brightness.
Did a quick basic check, just measuring frequency, did not try all the other features, will see later.
--> it works ! All those Nixies come to life and dance around to show me something.... though not quite what I expected...displayed frequency is, looks like, half of what it should be ! No worries.. decades boards are fine, must just be a failed frequency divider in the time base circuitry.... with 150 Germanium trannies in there, that's a lot of potential tin whiskers !!!
It's a miracle this counter can work at all really... I am not complaining.
Anyway, I had to tear it down right from the start because it uses a weird obsolete power socket, so I tried to get inside to solder a cable somewhere, just temporarily, to test it. No joy. spent half an hour taking it apart, removing bits and pieces of the chassis, a decade board, all the nixies and the bezel that keeps them aligned, a big bracket/gusset... only to realize that would only get me so far... but not far enough to solder a cable. So gave up and put it all back together again.
Well, at least it let me see how the thing is put together, check for its internal condition, and take pics for you, and for my archives.
So next time I get in there, I will know what awaits me.
Then when putting the face plate back on, one of the screws refused to "bite"... so left it out. No way I was going through the chore of taking this all apart and back again (it's a major PITA).. again, just to see what was wrong with that screw. They are tiny Philips head screws that suck big time. Most are in bad shape and even when in good shape it's all too easy to damage them, you have to apply so much force and pray so much that you won't damage the heads and that the screw will be kind enough to come loose... no. I hate these screws ! So I don't care for this "missing" screw as I think I will replace all of them with new screws with a different head style. I don't know, BTR maybe.
As for the power socket, it is long obsolete, I am 44 and it's the first time I see one like that. Old man said it was used for power hungry domestic appliances.. in the '60s. I was born in 77... yes I am just a kiddy sorry.
Don't want to spend a year, money and time getting (if at all possible...) the matching obsolete power cord... and don't want to have X bits of kit each requiring their own weird cord so... will be retrofitting a standard IEC socket. This is quite an undertaking.. will have to take this thing apart again, remove all the bits I already removed.. and 3 times more so I can actually work on this thing to fit the new socket. But well, no choice... otherwise I can't use this thing, and I DO want to use it, I am in love already. Might not show in pictures but it's such a cool looking piece in the flesh.
What's more ? When I got it... the amber colour filter in front of the Nixie tubes... had fallen off ! It appears it was held in place merely by some strips of foam all around the edges of the filter, pushing/pressing the filter onto the back side of the face plate... that's it ! Of course with time the foam as always, disintegrated completely so the filter was completely loose inside the cabinet... You can see the remains of that foam on the pictures... that disgusting looking brown-ish stuff...
This is now fixed already ! By some miracle I happened to have some foamy rubbery sticky "tape", of an appropriate thickness, 2mm or something I don't know, lucky me ! Cut some strips to size, got rid of the old foam, sticked the new foam into place... problem solved !
Being rubbery as well as foamy, it will give a grip on the filter, on its own, on top of the basic pushing-against-the-face-plate action, so should be good !
Anyway, so to sum it up, a pristine and lovely bit of kit I am delighted to have !
with the following to do when it's turn comes :
- Replace all the crappy philips screws holding the face plate, with a less rage producing screw type.
- Fit an IEC socket
- Troubleshoot and hopefully fix the time base issue so it can display the actual input frequency, rather than just half of it...
- Might add a web server with logging and remote control capabilities, to please Tautech ?
Attaching a few piccies...
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