Ricky <gnuarm.deletethisbit@gmail.com> wrote in news:3715ba7e-c395-4c2d-99d2-1e581eb4e383n@googlegroups.com: snip> Looking at the image in detail, it would appear you are right. > The solder doesn't look broken to me, it looks like it molded > around the contact, but never was a good solder joint. It > probably never really wetted the crystal contacts. >Blame RoHS. They disrupted the entire industry. Metallic based lead is not an environmental hazard. Otherwise the water tables around gun ranges (and land fills) would all be overtly contaminated and they are not. These are typical problems associated with lead free reflow soldering, which requires higher temperatures, but faster ovens to keep the thermal introduction into the parts low. Caused problems for the polymers the industry uses as well. Some no longer work well, some no way. If the ovens get set too fast a solder joint can appear to be good, but not be in actuality. And the acceptance standards allow a grainy look to be a pass as well. Both things I do not like to see, and this is one very good example of why. We do not see any mobo makers running their ovens too fast. A tray full of these cheap things though can endure higher fail rates both at the factory and in the field, so they crank the ovens up to increse output and thus profit from the contractor. Also, paste has an aging time limit both for exposed time in use and overall expiration time even in storage. So if the paste is out too long, flux based reflow failure can mount (or fail to mount).
I wondered why my garage remote didn't work.
Started by ●August 2, 2022
Reply by ●August 2, 20222022-08-02
Reply by ●August 2, 20222022-08-02
Ricky <gnuarm.deletethisbit@gmail.com> wrote in news:7915746f-2af8-4401-840f-772a7210f645n@googlegroups.com:> On Tuesday, August 2, 2022 at 8:55:16 AM UTC-4, Rocky wrote: >> On Tuesday, August 2, 2022 at 7:33:58 AM UTC+2, Sylvia Else >> wrote: >> > So I opened it up. >> > >> > https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 >> > >> > Seems fairly clear what the problem is. >> > >> > By why would the crystal fall off the board like that? >> > >> > Sylvia. >> The pads on the PCB look dull. As Clifford suggested, maybe the >> soldering was poor - at least on the crystal. The other joints >> are bright and look good. > > My understanding is the bright/dull thing went away with lead free > solder. I was shown photos from some document IPC maybe, that > showed the most horrible, grainy solder joints as examples of good > joints! Hard to tell from the crap joints. > >Absolutely correct. It is IPC acceptance. There are multiple levels (3), but most commercial follow the easy path.
Reply by ●August 2, 20222022-08-02
Joe Gwinn <joegwinn@comcast.net> wrote in news:06hiehdr516bfhjg5ita320pn9q7rb45ht@4ax.com:> On Tue, 2 Aug 2022 08:32:45 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >>Sylvia Else wrote: >>> So I opened it up. >>> >>> https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 >>> >>> Seems fairly clear what the problem is. >>> >>> By why would the crystal fall off the board like that? >>> >>> Sylvia. >> >>Looks like it might have got whacked by the battery when you >>dropped it on the floor. > > That would be my guess as well. > > Joe Gwinn >The battery looks like it would do it again as well. So it too need to fixturing like two 3 or 4mm holes at the free end near the crystal and a tiny tie wrap. Or a drop of holt melt small enough to be able to be sliced free for replacement.
Reply by ●August 2, 20222022-08-02
On Tuesday, 2 August 2022 at 18:07:03 UTC+1, DecadentLinux...@decadence.org wrote:> Joe Gwinn <joeg...@comcast.net> wrote in > news:06hiehdr516bfhjg5...@4ax.com: > > On Tue, 2 Aug 2022 08:32:45 -0400, Phil Hobbs > > <pcdhSpamM...@electrooptical.net> wrote: > > > >>Sylvia Else wrote: > >>> So I opened it up. > >>> > >>> https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 > >>> > >>> Seems fairly clear what the problem is. > >>> > >>> By why would the crystal fall off the board like that? > >>> > >>> Sylvia. > >> > >>Looks like it might have got whacked by the battery when you > >>dropped it on the floor. > > > > That would be my guess as well. > > > > Joe Gwinn > > > The battery looks like it would do it again as well. So it too need > to fixturing like two 3 or 4mm holes at the free end near the crystal > and a tiny tie wrap. Or a drop of holt melt small enough to be able > to be sliced free for replacement.The crystal can looks like it has glass-to-metal seals which will probably be made of Covar which needs to be plated to make it solderable. As suggested earlier, poor adhesion of the plating would give a weak joint. As it is a relatively large component there will probably have been considerable stress due to shrinkage of the pcb material during cooling after reflow. A mechanical shock from dropping the remote would make it ping off. John
Reply by ●August 2, 20222022-08-02
On 2/8/22 23:32, Fred Bloggs wrote:> On Tuesday, August 2, 2022 at 6:39:30 AM UTC-4, Clifford Heath wrote: >> On 2/8/22 17:06, Sylvia Else wrote: >>> On 02-Aug-22 4:01 pm, John Robertson wrote: >>>> On 2022/08/01 10:34 p.m., Sylvia Else wrote: >>>>> So I opened it up. >>>>> >>>>> https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 >>>>> >>>>> Seems fairly clear what the problem is. >>>>> >>>>> By why would the crystal fall off the board like that? >>>>> >>>>> Sylvia. >>>> >>>> This sort of item should also be secured to the PCB with glue. >>>> Easy to resolder if you have some lead-free solder (I assume). >>>> John :-#)# >>> >>> Glue wouldn't hurt. >>> >>> But if anything was going to fall off, I'd have thought it would be the >>> tactile switches. >> I've seen something like this. I think the crystal has the highest >> thermal mass (or lowest thermal resistance on its legs) of any SMD part >> on the board (the battery tabs are through-hole) and the solder reflow >> wasn't quite hot enough for long enough, so it got glued down by melted >> flux not melted solder, or the solder remained only sintered so it was weak. >> >> CH > > That's close but you would think they have all that ironed out after making gazzillions of fobs...99% of them are probably fine. This one was in the cold corner of the tray, on a day when all the local a/c units were pulling down the line voltage, or some similar thing. Only have to get 90% to pass the warranty period - you won't even hear about the 10% because it's less hassle to replace the fob than to complain. Clifford Heath
Reply by ●August 2, 20222022-08-02
On 02-Aug-22 10:32 pm, Phil Hobbs wrote:> Sylvia Else wrote: >> So I opened it up. >> >> https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 >> >> Seems fairly clear what the problem is. >> >> By why would the crystal fall off the board like that? >> >> Sylvia. > > Looks like it might have got whacked by the battery when you dropped it > on the floor. > > Cheers > > Phil Hobbs >Probably not. The image is a bit misleading. When the board is in the case, the battery is constrained to be more central in its circuit board slot, and cannot touch the crystal. Sylvia.
Reply by ●August 2, 20222022-08-02
Sylvia Else wrote:> On 02-Aug-22 10:32 pm, Phil Hobbs wrote: >> Sylvia Else wrote: >>> So I opened it up. >>> >>> https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 >>> >>> Seems fairly clear what the problem is. >>> >>> By why would the crystal fall off the board like that? >>> >>> Sylvia. >> >> Looks like it might have got whacked by the battery when you dropped >> it on the floor. >> >> Cheers >> >> Phil Hobbs >> > > Probably not. The image is a bit misleading. When the board is in the > case, the battery is constrained to be more central in its circuit board > slot, and cannot touch the crystal. > > Sylvia.If you say so. Per the picture, the metal shroud on the negative terminal wraps around the wrong side, leaving only the spring to keep the battery from hitting the crystal on impact. However, assuming the crystal survived, the fix is pretty obvious. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●August 2, 20222022-08-02
On 8/2/2022 6:53 PM, Phil Hobbs wrote:> Sylvia Else wrote: >> On 02-Aug-22 10:32 pm, Phil Hobbs wrote: >>> Sylvia Else wrote: >>>> So I opened it up. >>>> >>>> https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 >>>> >>>> Seems fairly clear what the problem is. >>>> >>>> By why would the crystal fall off the board like that? >>>> >>>> Sylvia. >>> >>> Looks like it might have got whacked by the battery when you dropped >>> it on the floor. >>> >>> Cheers >>> >>> Phil Hobbs >>> >> >> Probably not. The image is a bit misleading. When the board is in the >> case, the battery is constrained to be more central in its circuit >> board slot, and cannot touch the crystal. >> >> Sylvia. > > If you say so. Per the picture, the metal shroud on the negative > terminal wraps around the wrong side, leaving only the spring to keep > the battery from hitting the crystal on impact.I suspect that the PCBA is housed in a plastic clam-shell case that may very well have interior molded ribs designed to restrict movement of the battery when the remote is fully assembled.> However, assuming the crystal survived, the fix is pretty obvious. ;) > > Cheers > > Phil Hobbs > > > -- > Dr Philip C D Hobbs > Principal Consultant > ElectroOptical Innovations LLC / Hobbs ElectroOptics > Optics, Electro-optics, Photonics, Analog Electronics > Briarcliff Manor NY 10510 > > http://electrooptical.net > http://hobbs-eo.com >
Reply by ●August 2, 20222022-08-02
On 02-Aug-22 3:34 pm, Sylvia Else wrote:> So I opened it up. > > https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 > > Seems fairly clear what the problem is. > > By why would the crystal fall off the board like that? > > Sylvia.OK, I've soldered it back, and it works. It remains to be seen whether my soldering is better than the original. The most difficult aspect was getting it back into its enclosure, which seemed to be designed for assembly in zero-g, by someone with five hands, or something. Sylvia.
Reply by ●August 3, 20222022-08-03
On Tuesday, August 2, 2022 at 9:53:29 PM UTC-4, Phil Hobbs wrote:> Sylvia Else wrote: > > On 02-Aug-22 10:32 pm, Phil Hobbs wrote: > >> Sylvia Else wrote: > >>> So I opened it up. > >>> > >>> https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0 > >>> > >>> Seems fairly clear what the problem is. > >>> > >>> By why would the crystal fall off the board like that? > >>> > >>> Sylvia. > >> > >> Looks like it might have got whacked by the battery when you dropped > >> it on the floor. > >> > >> Cheers > >> > >> Phil Hobbs > >> > > > > Probably not. The image is a bit misleading. When the board is in the > > case, the battery is constrained to be more central in its circuit board > > slot, and cannot touch the crystal. > > > > Sylvia. > If you say so. Per the picture, the metal shroud on the negative > terminal wraps around the wrong side, leaving only the spring to keep > the battery from hitting the crystal on impact.You aren't looking at the case! -- Rick C. +- Get 1,000 miles of free Supercharging +- Tesla referral code - https://ts.la/richard11209
