I wondered why my garage remote didn\'t work....

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.
Click to expand...

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.
Click to expand...

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
Click to expand...

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.
Click to expand...

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...
Click to expand...

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
Click to expand...

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.
 
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.
Click to expand...

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
 
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.
Click to expand...

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
Click to expand...
 
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.
Click to expand...

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.
 
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!
Click to expand...

--

Rick C.

+- Get 1,000 miles of free Supercharging
+- Tesla referral code - https://ts.la/richard11209
 
On Tuesday, August 2, 2022 at 10:42:15 PM UTC-4, Sylvia Else wrote:
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.
Click to expand...

That\'s where they get the lowest labor rates.

--

Rick C.

++ Get 1,000 miles of free Supercharging
++ Tesla referral code - https://ts.la/richard11209
 
Sylvia Else <sylvia@email.invalid> Wrote in message:r
> 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.

It probably dislodged from thermal cycling. Common problem in the
auto industry.

Cheers
--


----Android NewsGroup Reader----
https://piaohong.s3-us-west-2.amazonaws.com/usenet/index.html
 
Clifford Heath <no_spam@please.net> 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.
Click to expand...

Correct. This is a common problem with larger parts, like coin cell
holders etc. They need more time to heat up so you don\'t get a cold joint.

I had a digital clock made by a PCB assembler that I got for free at some
trade show. Something fell off and I told them about it at the next show I
ran into them at and they actually offered to RMA and repair it for me as
they were embarassed about it.
 
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