On May 17, 22:11, Tony Duell wrote:
> > Yes, a common pitfall. I got bitten by that :-) And the 74150 has
the
> > same number and arrangement of pins as the 74ALS150, but one is 0.6"
wide
> > and the other is 0.3" wide!
>
> Most of the 24 pin chips in the 'modern' familes (things like the 74F181
> and 74HC154) are 0.3" wide. The 'traditional' ones (74181, 74S181,
> 74LS154, etc) are 0.6" wide. Don't ask how I found that out.
>
> Suffice it to say I have commerical instruments where the PCB was set out
> for a 0.6" wide chip. In said space is a header plug, soldered to which
> is the 0.3" 'modern' version with the pins bent out sideways.
:-) A solution I've seen is more "three-dimensional". Take one 24-pin
0.3"-wide wirewrap socket. Bend the pins so they fit into a 0.6"-wide
socket. Fit new IC to "upper" socket and fit this to the "lower" one. If
liked, mould "power bulge" into the hood. Or cut ventilation hole.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Thu May 17 2001 - 18:22:56 BST