[time-nuts] 5370a manual

[Didier Juges]

Hi Chuck,

Thanks for the tip. That's got to be the problem. I will take the CPU card out of the worst offender tonight and look under the magnifier.

Didier KO4BB

---- Chuck Harris <cfharris at erols.com> wrote: 
> 
> 
> Didier Juges wrote:
> > Well, one thing for sure, in both my units, the chips are not anywhere near ready to fall off. I need a crow bar to
> > take them out...
> > 
> > Same thing with the PWBs themselves, the card edge connectors are extremely tight, that's one reason I am puzzled by
> > the problems, there seems to be plenty of contact pressure.
> > 
> > However, the sockets really look like the cheap type, tin plated, not the gold plated, machined contacts type.
> 
> Oh, Oh!  One problem with the cheapy tin plated sockets is they develop tin
> whiskers that make minuscule little short circuits between the pins.  Bump
> the board, and they come and go.
> 
> I have solved this problem on some units by blowing high pressure compressed
> air all around the sockets.  Apple used to tell their service technicians to
> remove the circuit cards, and smack them hard edgewise on one edge.  Same for
> the mother board.
> 
> The only long term solution is to replace the sockets with something that doesn't
> have any tin plated sharp edges.
> 
> -Chuck Harris