Piggybacking 74LS logic chips to confirm a suspected fault

tony duell ard at p850ug1.demon.co.uk
Fri Dec 25 11:32:19 CST 2015

> In my experience, the type of socket you used is quite unreliable and
> will tend to develop bad contacts. There is a reason they are cheap... I
> would use a turned pin type socket instead, e g an Augat socket. They
> will not let you down. More expensive, but considering the work involved
> in replacing a socket and the risk of messing up the PCB, the cost is
> negligible.

My feeling is that for the sort of things most of us do here, a turned pin
socket is the most reliable of all. Yes, soldering the IC directly may have a 
(slightly) lower risk of bad connections, but given that we do (or at least I
do) component level repairs, may want to remove ICs for testing, etc, there
is a risk to the PCB if the IC is soldered directly. As you say, cheap sockets
are cheap for a reason. They do develop bad contacts!

I don't think I've ever had a problem due to a bad contact at a turned pin
socket. Not saying they can't happen, but it's very rare.

I use nothing else, both for prototyping and for repairs.


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