View Single Post
  #10   Report Post  
Posted to sci.electronics.repair
Andy Cuffe Andy Cuffe is offline
external usenet poster
 
Posts: 221
Default Why would pins 3 & 100 on a DDR DIMM fry?

On Sat, 26 Aug 2006 01:39:56 -0700, Unregistered wrote:

I may post the long story later, but the short story is that I have
a motherboard and a DDR DIMM where pins 3 and 100 on the DIMM and
the corresponding socket are toast. The gold on the DIMM contacts
is completely gone, and the socket is charred in those positions.

The motherboard was said to be dead when the DIMM was installed.

I've taken out the DIMM, and I put another DIMM into the computer
in a different socket, and it seems to work fine.

I took the burned DIMM and put it into another computer, and it
seems to work fine too.

What happened?

(I checked the DDR pinout. Pins 3 and 100 are both grounds.)



I would guess that a short occurred somewhere on the DIMM. It could
have been a ceramic cap that shorted, or possibly a short between
layers of the board. Maybe a foreign object like a screw hit the
DIMM. This caused the pins closest to the short to burn. Since there
are lots of Vcc and ground pins, it could still work as long as the
short is either no longer present, or was removed from the circuit
when the right traces melted.
Andy Cuffe