[c-nsp] heat fins popping loose on WS-X67xx cards

Jay Hennigan jay at west.net
Thu May 28 17:23:20 EDT 2009

> In the past 9 days I've found that 3 of our Catalyst 6500 WS-X67xx cards (2
> WS-X6748-GE-TX & 1 WS-X6748-SFP) had dislodged heat fins.  The fins are
> supposed to be tethered by a spring hooked into a small wire loop which seems
> to be soldered onto the circuit board.  In the case at hand the wire loop
> pulls out of the board & the heat fin then flops around free & in 1 case the
> wire loop was rattling around on the card.  Not good.
> I'm trying to determine if this is a systemic problem or just a fluke.  It
> seems like a design flaw, with the spring being too much for the soldered
> wire loop.  Has anybody else seen this?  If so, with how many cards & of what
> types?

It sounds like a design flaw.  The spring force on the loop is upward. 
Heat from the chip is conducted to the fins, the spring, and the loop 
which softens the solder.  Tension on the loop pulls it out.

They probably need to come up with a different means of attaching the 
loop, maybe a stamped part with a base on the underside of the board, or 
at the least use a high-melting-point solder for that attachment point.

Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
Impulse Internet Service  -  http://www.impulse.net/
Your local telephone and internet company - 805 884-6323 - WB6RDV

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