---snip---
As for the vertical alignment "problem" of the ***** tubes, had a first look at it and looks like the answer is simple : the mechanical design of the counter just does not permit to hold the boards firmly in place, never mind an accurate place...
Turns out the boards do NOT have a card edge connectors... no. They have proper board to board connectors. Connector is made of thick round pins.
Those blue connectors are very familiar, even though the make is different. We worked on lots of old BR equipment from the 70s & 80's that used those, but the connectors were made by Smiths & later Hypertac. Pretty sure we had extenders in that size, but probably long gone now, not that I could buy them if they are still there (still won't sell any redundant TE).
I looked in the parts list but they don't list these connectors sadly !
.. so short of getting some from work, if you could if just find some old databook or something to identify them, that would be a big help, I could try and Google for them and maybe with some luck find some for sale. I guess I could salvage a male/female pair from the donour counter, but I would rather try to keep it complete as much/ as long as possible, in case I get the silly idea one day of restoring it.
But for now, for parts it is... the more I look at it, the more I take it apart... the more it scrams " don't bother, I am done for, am too far gone... ".
Like, I looked at each and every Nixie board in detail last night..... it's a disaster.
The two fastest boards (50MHz and 10MHz) are intact and working at first glance (which is good because these two I are buggy in my good counter). The 2MHz board has two transistors replaced, but it looks clean and tidy, I don't mind. However the other 5 boards, the slow 300kHz ones.... oh my Goodness, they have all been butchered like hell. On each board, every single one of the 8 trannies has been pulled. Sometimes the original one was put back in place, sometimes a modern shiny looking transistor was put it, and sometimes an old / period tranny was used, but a different, much bigger package, hence of course a different part number. Parts list does say that all these trannies are supposed to be matched, BTW....
The solder job is what put the last nail in the coffin. It looks like a battle filed. Missing pads, lifter pads or tracks, and many trannies had missing solder joints. Sometimes the pad on the top side (it's a double sided board) was not connected to anything, so OK no big deal.. but sometimes there WAS a track going to that pad yet still now solder joint !
It's just... just horrifying.
I swapped the plugin and tried the working one from my good counter... I can now get it to count but it shows now other problems... display only works in "latched/memory" mode, you can't see it counting anymore, should you want to. Also the gate opening time setting is half gone : only the lower half of the settings appear to work (then the lowest resolution settings of the counter), the upper half doesn't work at all, counter fails to count and just display s a solid all zeros.
One of the nixes also sometimes looks like it's "arcing" internally... there is a fuzzy blob of light between the '0' digit and the glass envelope..
This, and other little things... clearly the guy worked heavily on this thing, but massacred everything he touched.
It was sold for parts for a good reason it seems ! I bought it for parts to begin with, and looks like it's gonna be for parts, indeed...
There are some good news though.
- 50MHz and 10MHz boards are intact as I said, and these are bad with a hard to diagnose fault, in my better counter. So it's good to know I can just swap these boards, at least short term, to get the counter going. Then might try to troubleshoot the later...
I would only at first try to trouble shoot the third faulty board, the slow 300kHz one, because its fault is solid, permanent, so easy to work on. Can just probe at will until I figure it out.
- Its for part status means I can allow myself to salvage connectors from tit ot make an extender card.... though as said above that would be a last resort, only if I can't identify and buy new connectors....
- Conformal coating / debugging : tried to pierce it with sharp probes... doesn't do it. My 'SMD' probes are to fragile. Then tried bigass Hirshmann insulation piercing, 4mm probes... the sharpest I had. Now these work but only if the board is laying flat on the bench and you apply so much force that it's ridiculous. Not going to be a viable option when the board I want to probe is vertical, loosely hanging in the air on an extender card.... So, I give up on probing though the coating.
HOWEVER... I noticed that the coating, which still has not hardened despite being 50+ years old, can easily be soften with gentle application of hot air for a for a few seconds only, then it can easily be scrapped off of the board with a sharp blade. So, knowing that... I though well what about a soldering iron... so I tried to wick a joint, and it worked just fine ! Just do as if there were no coating... takes only a few seconds for the coating to melt, then the iron tip gets to the solder underneath and the wick works just fine. You just need to push the melted coating residue away from the joint using the iron tip, and that's it. So... looks like I should be able to troubleshoot these boards easily then : just need to remove a tiny bit of the coating at the test points of interest, and that's all !
- While skimming the parts list trying to find the connectors, in vain, I spotted a 2N2222 tranny listed !! What ?? This late '60's counter (oldest page in the manual is dated October 1967), but it has a "modern" fancy SILICIUM tranny in it ?!
Thought these old counters were Germanium !
So, I checked the part numbers for the decade/ Nixie boards.... the 50MHz one uses a STE401 transistors, failed to find a datasheet for it. If you have it in some old paper catalogue, please share.
Then looked the 10MHz board, it uses a 2N3639. The 2MHz and 300kHz boards use a 2N3638. Looked them up, both a PNP SILICIUM not Germanium, hooray !!!
Will make substitution much easier if need be !
Hell I just Googled them for vendors, looks like the 3638 which is the one used in 6 of the 8 boards as I said, is easily available, there are NOS out there !
3+ Euros a pops.. well I only need to change a few I guess, not 200 hundreds of them, so that's OK.
The faster 3639 is harder to find a twice the price, but there is some on Ebay it looks.
Cool..... so it looks like all the stars are aligned, I should be able to fix my boards !
P.S. If you find any-more of those Ferisol counters I'd be interested in one.
David
OK, noted !
You can also check the website as I do, two sets of eyes are better than one
https://www.leboncoin.fr/recherche?text=ferisol&shippable=1&sort=timeThe link includes the search term.
"Ferisol" is specific enough of a name that 100% of the search results are relevant. There is no other "Ferisol". So you will not be spammed with irrelevant content, like one is when searching for " HP ", say !
If you find one there of course I will be your middle man
I never check Ebay but if you do, maybe you will find one there, I don't know...