Products > Test Equipment
HP Logic Analyzer Inverse Assemblers
MarkL:
Those are not in great shape, but I've had worse. I wouldn't plug anything into them the way they are. You might ruin the connector on the flat-flex cable.
I would try using a soft bristle brush saturated in IPA (like a toothbrush), and try to gently scrub the green corrosion off the fingers.
If that doesn't work, and I know some people are going to hate this suggestion, you could try a very fine bristle brass brush. I have had to resort to this in a few cases, but in my view it was a doomed connector anyway, so what did I have to lose. I recall one connector where it was so bad I had to scrape the corrosion off with a needle finger by finger. I made a mess of the gold plating, but it did work afterwards.
I've found the connectors on the top side of the board are usually in much better shape. If you're good at SMD soldering, and you have good connectors on the top, you could try transplanting a pair to the bottom on one of the boards. You have 8 connectors to work with, and you only need four to get a pair of boards connected (two on the top, and two on the bottom).
I will look around to see if I can figure out the manufacturer, but there are no identifying logos or other tell-tale marks. The only thing I see is "RN 004" on the flat-flex side. I seem to recall a connector manufacturer with the initials "RN" long ago, but I can't recall who it was. But it's not clear that's even the manufacturer.
ahakman:
I ended up doing exactly what you suggested - I spent a couple of hours this afternoon looking at board to board connectors at Digikey and Mouser and couldn't find a match, so it was on to plan B:
I spent at least a couple of hours under the microscope scraping each individual pin in the 2 connectors on the bottom side of one card with a sewing pin, and a very fine tipped "grinding pen" (if you watch Northridge Fix on youtube, you know what I'm talking about) bit just by hand. I also finished up by running a spatula with printer paper wrapped around it as a final "polish" back and forth in the central slot of the connector. That's a trick I learned many years ago - printer paper is just abrasive enough to use for cleaning up contacts without damaging any of the metal of the connector. Also used the pin and some cotton from a cotton bud and acetone to soak up all the mess, and some compressed air to blow out what was left.
First time I ran the cards together, I had 2 failing self tests, inter-chip resource bus and one of the clocking tests both failing on the slave board. Took it apart again and did a little more scraping, polishing with the printer paper on the spatula, and cleaning again with compressed air, and on the second try, it's working!
I did also use a tiny dremel sized brass brush too - again, by hand, not in any tool that would spin it, and I tried cleaning the contacts on the bottom connectors of the other board without doing any scraping first - it definitely didn't get some of the bigger "chunky" stuff off, but it looks quite a bit better. Scraping each pin individually is definitely the way to go. If I get some more boards in the future and need to use the bottom connectors on that board, I'll have to do some more manual scrapey-scrapey under the microscope to get those contacts in good shape.
All in all, the plating doesn't look perfect anymore, but it is working.
What an absolute journey it's been to get to this!
2 Cards linked together into one "analyzer", the IA compiled and inserted, and actually seeing all of the defined buses now! And 2 sets of the cables I bought showed up today too, so I'm technically ready to run this! Now I need to get the target system ready - that's a bit of a project in and of itself. Tomorrow - I'm way too tired today.
MarkL:
Great - glad you got everything working! Popping the stack...
Thanks for the ref on the "grinding pen". Looks like a useful tool. I'll have to grab one of those.
ahakman:
On the Grinding Pen, the one Northridge sells you can find for about half price on Ali Express (of course).
I bought one from Ebay that looked like the same thing but with a different set of bits - I don't think it's the same thing at all. The bits in the ebay one seem considerably worse than the bits in the Northridge / Ali Express one.
I'm waiting on the Ali Express one to actually arrive to be able to compare it to the ebay one.
The bits from the ebay one did come in handy for this little job though...
If you want the good one and you want it reasonably quickly, just support Northridge Fix and buy it from him!
MarkL:
--- Quote from: ahakman on March 04, 2023, 09:08:58 pm ---...
If you want the good one and you want it reasonably quickly, just support Northridge Fix and buy it from him!
--- End quote ---
I'm going to do that. There were a few other things in his store of interest, not to mention a nice metal bristle brush for "Circuit boards and corrosion removal". Just what was needed!
Also, the name of the company with the RN logo (remembering from decades ago printed on wire-wrap IC sockets) was Robinson Nugent. They are now owned by 3M, and inherited the 0.8mm connectors which are used on the analyzer boards for the interconnects. See Pak 8 Plug Connectors and Pak 8 Socket Connectors here:
https://www.3m.com/3M/en_US/p/c/electronics-components/interconnect-products/pcb-connectors/boardmount/i/electronics/
Or, go directly here for the sockets that are on the board:
https://www.3m.com/3M/en_US/p/d/b30000132/
The part number looks like it would be P08-080-SLxx-A-G, where the xx depends on packaging and vacuum pickup options (see datasheet). Quest Components has 92 available for US$5.70/ea according to octopart.com. I've never ordered from them, so I don't know how well they cope with small orders.
Just posting the info in case anyone is ever looking for these again.
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