On 2017-09-22 19:47, Larry Stotler wrote:
On Fri, Sep 22, 2017 at 11:50 AM, Stevens <fred-n-sandy@myrhinomail.com> wrote:
Anton - with the advent of surface mount and the Chinese penchant for playing the "I can do this with less than you" game, sometimes all you have to do is glare at a pc board and the solder connection will break. Their reluctance to use expensive (HAH!) solder isn't limited to boards, either. Sometimes cable failure analysis finds no solder at all. Manufacturers rarely use statistical sampling of output; nowdays they look at the returns percentages and sales numbers. Whatta world, whatta world.
Lead free solder is a big part of the problem. It's no coincidence that gpu chips started pulling off when they made the switch. HP resorted to using epoxy at one point to try to hold the gpus to the motherboard, which made it almost impossible to re-ball the chip. Made a bunch redoing the gpus years ago with regular solder and rarely had any come back.
Lead free solder means higher soldering temperature, for starters. Worst, controlled temperature. And more expensive if silver is added. Higher temperature means that the old PCBS can't stand the heat. Soldering stations are also different, they need to control a precise temperature. If silver is a component of the solder, then one applies the solder as if one is Ebenezer Scrooge. Lead free solder is not mandatory, but recommended. However, many institutions may contract for "lead free" solder, and then you have to comply. -- Cheers / Saludos, Carlos E. R. (from 42.2 x86_64 "Malachite" at Telcontar)