On Wed, Apr 22, 2020 at 02:36 AM, victor.silva wrote:
I know. I was referring to the amazing improvement in copper trace bonding that has happened since the '70's when traces could easily be pushed away with a hot soldering iron.
The 2445/2465 families lie between the two extremes, timewise.
I know, of course, see above.
Re. the twisting method, I was specifically referring to the TDS400/500/600 families, with many dozens of leaking caps each.
My most recent experience reconditioning a 2445/2465-family instrument (A5 caps, PS caps, mains filter caps, NVRAM/FRAM) is about 3 years ago.
My current instruments from that family are a 2465B, a 2467B and a 2467BHD. All have SMD-equipped A5's and none were so bad that pads were gone or even came off while working on them (yes, mostly using the twisting method). In fact, only the familiar matte solder surface gave away the leakage, no real corrosion visible.
I remember some other samples that were in much worse shape. I unsoldered some caps in those. Never lost a pad unless it was coming off already.
My 3 units above certainly don't have conformal coating, if you're talking about a thick layer, covering the whole pcb. Never seen it on one of those instruments even. Nice!
I doubt if perpendicular forces put less stress on the pads than forces almost purely in parallel with the pad/pcb interface.