I will have to check with other engineers how much of a problem the fiberglass embedded in PCBs can be a problem to female edge connectors and what impact they can have on their lifespan.norm8332 wrote:Yeah, but unfortunately that doesn't include what I know is an issue with the unnecessary beveling of the fiberglass boards. It is clear to me that this is a serious wear issue. The problem is all of these designs including in the link you provided are for use for a pretty limited lifespan. We are trying to extend the lifespan.
Your posts triggered my curiosity and I decided to check my own Ultimate Expander which I made (and sold) back in 2006-2008. Since I lacked experience at the time, I had left other qualified people to take the PCB fabrication decisions about this product. It's gold plated only on the edge connector with hard gold plating and, to my surprise, it's a resin board - no fiberglass. Looks like there are benefits to leaving some stuff to experienced people.
This being said, since even Vector makes their boards with fiberglass, I suspect it has a much smaller lifespan reducing impact compared to using HASL on an edge connector.
Also, if you look at the old vs new Behr-Bonz photo posted here: http://sleepingelephant.com/ipw-web/bul ... &start=194
... you'll see the old one is also resin only and it is gold plated in exactly the same way the Ultimate Expanders were. That's because the company which made both the Ultimate Expanders' PCBs as well as those from the first batch of Behr-Bonz is the same one. Multifor is unfortunately now out of business.
Hard gold plating restricted to the edge connector, the absence of fiberglass in the PCB material and the absence of a soldermask are the 3 distinctive features of these PCBs.
Added edit:
I have a bunch of various 44 pin boards with 0.156" spacing edge connectors. These include a Vector 3662 (still in stock at Digikey!! mine must be 30 years old), a Vector 3474-2 (discontinued), a Radio Shack 276-187 and another Radio Shack 276-154A. All of these use resin only PCBs; no fiberglass.
This being said, the Radio Shack boards have no gold plating. The 276-187 is solder only (lead-tin which predates HASL) and the 276-154A is even worst with bare copper.