I wondered why my garage remote didn't work.

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 :-#)#

leaded solder is fine (and easier) for rework

Glue wouldn't hurt.

But if anything was going to fall off, I'd have thought it would be the tactile switches.

Sylvia.

Maybe the switches are supported at the top by a membrane or buttons?

Is it possibly the battery could move enough to touch the Xtal?

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

No reason for the switches to fall off. They are always being pressed ONTO the board.

The crystal solder probably was cracked when it was dropped at one point, but it kept working until both joints failed.

Looks like it might have got whacked by the battery when you dropped it on the floor.

Cheers

Phil Hobbs

Probably knocked around during battery replacement.

RL

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.

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.

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.

Crystal leads were not plated adequately with compatible alloy/metal (copper/silver or alloy) to make a good solder joint, or the part was not stored properly in manufacture and corrosion or oxidation on the leads took place before being soldered to the board. You can't make a proper solder joint between any old combination of metals. It's definitely a bad solder joint. Shock effect is not a possibility because a proper joint will tear the board pads off and/or show visible damage to the component before it lets loose.

That's close but you would think they have all that ironed out after making gazzillions of fobs...

That would be my guess as well.

Joe Gwinn

That's not the way commercial devices work. They make them and keep making them the same way until something forces them to change it. The fact that someone broke their keyfob by dropping it, is not material to them.

Besides, we haven't seen the case. I'm willing to bet there is a barrier that prevents the batter from contacting the rest of the electronics.

Sylvia Else snipped-for-privacy@email.invalid wrote in news:jkrra0Faji0U1 @mid.individual.net:

You can blame RoHs for that. Shitty lead free solder joints nowadays get inspected as passed, even when grainy and full of micro-fractures. Likely a bad plating on the part legs as well. Does not look like it would take many jolts to tear free from the pads.

Those two tiny pads can be re-soldered with 63/37 tin lead solder and it will be reliable. It is allowed for servicing. Use a flux pen to wet the pads after you have braid-wiped the them to remove the previous solder remnants. Clean up the legs of the part too, but only a quick reflow cleaning as it will introduce heat into the part directly. Actually the legs look clean enough, maybe look at the bottom side of the legs to see if the cladding remained on the board. If so, a re-tin is needed and just hope the heat does not cause an internal detachment.

John Robertson snipped-for-privacy@flippers.com wrote in news:PDidndcQqqY_IHX snipped-for-privacy@giganews.com:

Most labs doing service on RoHS lead free assemblies are permitted to use 63/37 Tin Lead solders on lead free board for the repair. This includes Europe's rules, not just the US.

Reflow assemblies use lead free OK, but in a repair lab, getting a non-grainy connection is not as easy, so most techs use the old tried and true and the rules for RoHS allow it.

Clifford Heath <no snipped-for-privacy@please.net wrote in news:170780f29fb86497$1$1950103$ snipped-for-privacy@news.thecubenet.com:

Good analysis. Lead free is a hotter reflow, and cost cutting makers spool up their reflow ovens as fast as they can get away with.

It may have soldered, but the part legs might have poor plating/cladding choices made by the maker as well.

The pads do look like they did not quite reach good reflow temp though.

Use 63/37 to fix. And glue... hot melt should be fine. A dab on each long edge.

Ricky snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

All the more reason to fall off. You seem unfamiliar with "solder creep". Even the axis they get impinged on contributes. They more likely simply did solder up right in reflow, whereas these two legs did not. One countertop drop is all it takes. And the switches then recieve the same side forces then as well.

Looks more like a single event detachment to me.