[time-nuts] HP 5370B low frequency modulation

[Magnus Danielson]

From: SAIDJACK at aol.com
Subject: Re: [time-nuts] HP 5370B low frequency modulation
Date: Thu, 26 Jul 2007 14:51:27 EDT
Message-ID: <d6b.b2db71f.33da472f at aol.com>

Said,

> Hi Magnus,
>  
> I've had a board with what the manufacturer called "black pad" syndrom: the  
> BGA literally popped off by just bending the PCB sufficiently. The solder 
> joint  was useless.
>  
> Is this caused by the problem you described?

It is the only reason I know if you use a propper soldering profile while
soldering the BGA.

> Also, what do you think is a better process: gold-flash, or  gold-immersion?

No preference. The important thing is the relative amount of gold, and that
relates to the thickness of gold. A good process on gold-plating is crutial
regardless of method.

Cheers,
Magnus