Electronics > Repair
Series defect on agilent 167xx boards?
MarkL:
Is your board a 16533-66504 on the stickers in the lower right? I have one, but before I dig in I wanted to confirm because it's not clear in your photo.
DogP:
--- Quote from: MarkL on February 11, 2022, 09:49:53 pm ---Is your board a 16533-66504 on the stickers in the lower right?
--- End quote ---
Yes, that's correct.
MarkL:
Ok, I've done the verification with my 16534-66504 board. It's the same as your 16534-66504 except for the model setting resistors, as far as anyone knows.
I can confirm the resistances are the same for both the A and B vias that I posted before.
After tracing with the I-prober...
The A endpoints are correct as previously shown. I was unable to find that A goes anywhere else.
The B endpoints are numerous. In most locations where you'll find B, you'll also find a 68.1R termination resistor and an MLCC. That's no surprise. There's a ton of them on the back near the center of the board.
The internal trace at the broken B via goes horizontally in both directions parallel to the edge of the board. I was not able to find any trace that went vertically coming out of the broken via. If you look at the photo, there's another B via to the right. I'm guessing the purpose of the broken B via was to change layers, and then probably went back to the original layer with the B via on the right. From that via, the B trace continues on towards the front of the card, turns up until it gets to the external trigger output, and then dives back towards the center of the board where it appears to power most, if not all, of the ECL terminations. I can image lots of things would break if these terminations did not have power. Most likely this was your trigger failure.
My suggestion would be to jump the left B via/traces and the right B via shown in the photo near the bottom edge of the board.
DogP:
Awesome... thanks SO much for all this info! Hopefully I'll get this fixed up tonight. And hopefully the seller on ebay gets around to shipping the LA card/cables that I ordered sometime soon, so I can get that other board repaired, and start putting this machine to use. :-P
Thanks,
DogP
DogP:
Got this board repair wrapped up... added the jumper wires as you recommended, tacked it down with some nail polish, and everything seems to be 100%.
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...
Thanks again for all the measurements, pics, etc! I'll post if I make any progress on the 16750B, WRAP flag, etc.
DogP
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