soldering crystal oscillators

Actually, I have found that it's rather unusual nowadays for Japanese documentation to be that poorly translated.  It used to be quite common.  My experience with crystals is that some cannot take the heat of IR reflow soldering, so you have to hand-solder them later in the manufacturing process.  This could very well be the case with RasPi, and people have reported manufacturing defects such as bent through-hole pins.  I know I'll be checking my RasPi carefully before plugging it in.

Here's what Citizen's web site has to say:

When heat is applied across the crystal (such as reflow oven for example) is very small cage, and because the injection method of soldering, it may significantly degrade performance, avoid using Please.

 

http://cfm.citizen.co.jp/english/product/cvo_manual.html

see paragraph 1.II.3.

I don't know if RasPi's cage is very small or solder is being injected.

John,

  You're probably right about the crystals being hand-soldered.

We've seen what appears to be evidence of hand-soldering on

the back side of the board:

http://www.raspberrypi.org/phpBB3/viewtopic.php?f=6&t=6124

and there isn't much else on the back side that looks like a

candidate for hand-soldering.

I thought things like bent pins and stray solder blobs were supposed

to be detected by visual inspection, or automated optical inspection,

at the factory.

I'm saddened that Pete seems to have changed his mind about talking tech with us on Element 14.

The conversation about polyfuses ended up being totally one-sided with a grand total of zero contributed to our understanding by the Foundation, when it would have been far better as an open Foundation-community dialogue about Pi power design.  These crystals are another area of the Pi where this applies.

Wish they'd talk openly.  Secrecy has no place in a project with such worthwhile educational goals.

Morgaine.

coder27 wrote:

 

John,

  You're probably right about the crystals being hand-soldered.

We've seen what appears to be evidence of hand-soldering on

the back side of the board:

http://www.raspberrypi.org/phpBB3/viewtopic.php?f=6&t=6124

and there isn't much else on the back side that looks like a

candidate for hand-soldering.

 

I thought things like bent pins and stray solder blobs were supposed

to be detected by visual inspection, or automated optical inspection,

at the factory.

Through-hole parts are often hand-soldered as well.  It can be hard to wave solder SMT components.  I'm told you have to be careful how you orient resistors and capacitors or you get "tombstoning".

coder27 wrote:

 

John,

  You're probably right about the crystals being hand-soldered.

We've seen what appears to be evidence of hand-soldering on

the back side of the board:

http://www.raspberrypi.org/phpBB3/viewtopic.php?f=6&t=6124

and there isn't much else on the back side that looks like a

candidate for hand-soldering.

 

I thought things like bent pins and stray solder blobs were supposed

to be detected by visual inspection, or automated optical inspection,

at the factory.

Through-hole parts are often hand-soldered as well.  It can be hard to wave solder SMT components.  I'm told you have to be careful how you orient resistors and capacitors or you get "tombstoning".

http://www.npiengineer.com/tombstoning.html