Electronics > Repair
Series defect on agilent 167xx boards?
MarkL:
Great! And you're welcome! It's challenging and fun troubleshooting this old technology.
I assume you saw some of the posts to upgrade your 16533A to a 16534A?
--- Quote from: DogP on February 12, 2022, 10:36:03 am ---...
BTW, it looks the 9 ohm measurement on my board was the connection from the left 'B' to the middle 'B'. I had 0 ohms from the middle 'B' to the right 'B'. Weird...
--- End quote ---
Yeah, that's strange. My probing showed it was a direct shot from the left B to the middle B. Maybe the connectivity to the left trace inside the via is/was damaged by the corrosion on your board.
I'll look forward to your posts on the 16750B, and maybe the 16716A when you get to it. The 16750B is a much more capable module, and can be upgraded to a 16752B, so you might not miss having a 16716A. But then there's the nagging, "Well, I might be able to fix this..."
DogP:
>I assume you saw some of the posts to upgrade your 16533A to a 16534A?
>can be upgraded to a 16752B, so you might not miss having a 16716A.
Yep, once I tested the cards unmodified (to make sure I knew the state they were in when I started), the first thing I did was "upgrade" all of them.
>But then there's the nagging, "Well, I might be able to fix this..."
Heh, that's exactly what I'm expecting will happen. Though I don't even know the state of it right now... it could be completely trashed, or it might even be working. The seller put "for parts", which could mean anything.
BTW, I did a quick search through some of the binaries for the wrap flag stuff, and it appears to be part of the Zoom FISOs. There's a string "FISO wrap initially TRUE", "FISO Wrap Flag never went TRUE", and "Unable to Detect WRAP Flag" (which is what I'm getting)... all in the same vicinity of other Zoom strings. So I think I'm sticking to the plan of mapping those pins as much as possible, and maybe trying to run my finger across the FPGA pins to see if I can cause one of the other FISO wrap flag errors (if it's floating, hopefully my finger will change its state).
DogP
DogP:
Just figured I'd post this real quick... I ended up making an extension for these cards using some IDC connectors and a ribbon cable. Pretty janky, but it seems to work. I wanted to test it before laying out a PCB and waiting for it to arrive... then finding out it just doesn't work. :-P
So, if I get a few free minutes this week I plan to make an adapter to use two IDE cables, since they're readily available, and in lots of different lengths. No idea how long of a cable will work, but it doesn't sound like the backplane has any really high speed signals, so hopefully reasonably long. I just want enough that I can lay a board either side up on my bench. If a long cable works, I guess you might be able to come all the way out the back.
Edit: I did some testing with it on my WRAP flag board... by putting my finger on/near some of the zoom chip pins, I was able to consistently get the WRAP flag message several times in a single zoom chip select test. So, maybe the WRAP flag itself isn't the problem, but instead pins are floating when they shouldn't be (chip select, R/W pins, etc?). I'll have to probe those chips some more. And to confirm that was a valid test, I took my good board and put my finger on the same pins, and had no failures.
DogP
DogP:
I put this together this morning, and have it on order... the same board can be used for both the backplane and card sides, just populate the connectors appropriately. And from the 1:1 printout, it actually looks like it'll fit perfectly between slots, so I guess maybe you could use multiple to debug a master/slave configuration on the bench or something.
I'll post the gerbers once I receive and test the boards (next week hopefully?).
DogP
DogP:
They FINALLY got around to shipping the 16716A, and it arrived today. Overall, the card is pretty clean, and seems like it might be fairly new, since all of the adhesive strips peeled off in one piece (I used heat, of course).
From an initial look, there's not much corrosion, though the little bit that I do see seems to be at a few vias, particularly under the BGAs, which of course sucks. But even those look pretty minor compared to the other boards I had corrosion on. The nastier part is some goop that's stuck to the top of the board and on the cables... doesn't look corrosive or anything, but kinda sticky, like someone's kid got too close to it with a piece of butterscotch candy (probably more likely that it's something like a dried up glop of paste flux that someone spilled on it on their workbench). So, I've got some cleanup to do, as well as taking a very close look at traces/vias/etc. under the microscope.
Anyway, I plugged it in, and it shows up in pv as "(0x2f) Unrecognized module". Any ideas on what causes that? Part of me wants to suspect bad solder joints on the 208-pin QFP near the backplane connector... past experience has been that large QFPs on large boards that flex easily is a recipe for solder joints to pop free. And I'm guessing that's the chip that communicates to the host, so it seems plausible. I didn't see any pins that looked to be lifted, but I plan to look more closely at that later as well.
Thanks,
DogP
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