HP Forum Archive 20

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Re: Does anyone have 15C LE dissection pics? Message #1 Posted by uhmgawa on 24 Oct 2011, 2:42 p.m. ..in response to message #26 Posted by Eric Smith on 22 Sept 2011, 5:45 p.m., ..in response to message #25 by uhmgawa Quote: This is what makes it particularly bizarre that the 15C LE has moved to SMT assembly. I still boggle why following up directly to a thread merely a month old in this forum is verboten, but anyway.. I finally heard back from Atmel (through their 3rd party die reseller) who declined to quote our bid on the at91sam7l128 citing the device in die form was either in, or will soon be EOL. I speculate that was the primary motivation for the board layout change to accommodate the 128 lqfp in the new ARM voyagers. Not too surprising as the sam7 is getting rather long in the tooth and there hasn't been any follow on AFAICT to either l64/l128 version. Also other more recent vendor designs exist with improved performance/power capability. Yet despite its age the sam7l appears to still have some competitive differential particularly given its price point.

Re: Does anyone have 15C LE dissection pics? Message #2 Posted by DigiGal on 24 Oct 2011, 10:23 p.m., in response to message #1 by uhmgawa Check this archived thread, Djj posted some great pics to photobucket from his keyboard modification. Katie posted some dissection pictures too further back in the archive.

Re: Does anyone have 15C LE dissection pics? Message #3 Posted by uhmgawa on 25 Oct 2011, 12:29 a.m., in response to message #2 by DigiGal Quote: Check this archived thread, Djj posted some great pics to photobucket from his keyboard modification. M1.4 x 4mm (or perhaps x 5mm depending on washer thickness) is just about ideal. I'd initially tried M1.2 x 5mm screws however due to the thread major diameter routinely running undersize for such a fine pitch, an M1.2 screw doesn't have much (if any) penetration into the stake void walls. I also expect substantial variation exists relative to screws and enclosure molding run. However the M1.4 thread needed to be formed with a tap in my case as the fit was too snug. Machine screws will wedge vs. cutting threads and unless tapped there is a risk of randomly splitting the heat stake. Another possibility is to intentionally slice the stakes in half lengthwise allowing a controlled expansion/wedging within the pcb. But use of a plug tap is probably an overall simpler approach.

Re: Does anyone have 15C LE dissection pics? Message #4 Posted by DigiGal on 25 Oct 2011, 10:55 a.m., in response to message #3 by uhmgawa Read the whole thread. . . He posted the picture link further down the thread.

Re: Does anyone have 15C LE dissection pics? Message #5 Posted by uhmgawa on 25 Oct 2011, 8:39 p.m., in response to message #4 by DigiGal Quote: Read the whole thread. . . Yes, I had. My point rather was I'd originally suggested use of M1.2 screws after casually gauging the stake voids and neglecting to compensate for the typical clearance-reduced major diameter. So M1.4 is a better standard size for the task. Still the use of a machine screw in ABS is unorthodox. The no-holds-barred approach would be to (slightly) drill out each stake void and heat-press in a threaded section of 1.6mm (1/16") brass tubing tapped in advance for a M1.4x0.3mm thread. While the above admittedly is extreme for an ARM voyager, true hardship cases exist begging for similar treatment such as the 42s "write once" enclosure.

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