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.

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 :-#)#

tirsdag den 2. august 2022 kl. 08.01.31 UTC+2 skrev John Robertson:
> 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).

leaded solder is fine (and easier) for rework

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.

Sylvia.

On 02/08/2022 08:06, 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.
>
> 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?

--
Cheers
Clive

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

On Tuesday, August 2, 2022 at 3:06:19 AM UTC-4, 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.

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.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

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

--
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

On Tue, 2 Aug 2022 15:34:00 +1000, Sylvia Else <sylvia@email.invalid>
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.

Probably knocked around during battery replacement.

RL

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.

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.

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.

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209

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.

--

Rick C.

-- Get 1,000 miles of free Supercharging
-- Tesla referral code - https://ts.la/richard11209

On Tuesday, August 2, 2022 at 1:33:58 AM UTC-4, 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?

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.

>
> Sylvia.

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...

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

Sylvia Else <sylvia@email.invalid> wrote in news:jkrra0Faji0U1
@mid.individual.net:

> https://www.dropbox.com/s/4qb9x10tnczm3x8/remote.jpg?dl=0

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 <spam@flippers.com> wrote in
news:PDidndcQqqY_IHX_nZ2dnZfqnPqdnZ2d@giganews.com:

> 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 :-#)#

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_spam@please.net> wrote in
news:170780f29fb86497$1$1950103$e2dde862@news.thecubenet.com:

> 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
>

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 <gnuarm.deletethisbit@gmail.com> wrote in
news:bbc8438b-47dd-456e-b075-fdb5f5f3052dn@googlegroups.com:

> On Tuesday, August 2, 2022 at 3:06:19 AM UTC-4, 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.
>
> No reason for the switches to fall off. They are always being
> pressed ONTO the board.

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

Looks more like a single event detachment to me.

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).

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.

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.

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

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

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.