SB-104A Counter Circuit Board

[David Ritchie]

JF writes:
>The sockets on my SB-104A counter board caused so much trouble that I
>finally removed all of them and soldered the ICs directly to the board.
>Fixed the problem, but not having sockets makes it harder to do
>troubleshooting if an IC goes bad later. You might consider buying some
>high-quality sockets and replacing all of the originals. Try to find
>some with gold-plated contacts that are closed at the bottom and will
>not allow solder and flux to wick into the contact areas.

  As you mention later, sockets are a cause of a lot of problems. When I 
worked at HP, they almost never placed sockets on boards as they were 
evidently a major source of failures. Read as: "Sockets are evil!" 

  I would recommend against using sockets. I have found that the problems 
with them over time outweigh any advantages for production boards. The only place I would even recommend them is with EPROMs, and I would then
lean towards the high quality sockets as discussed earlier. If is something that was going to see a lot of vibration, I would not use them 
at all.


  Instead, solder the IC directly to the board, and when/if it fails, cut the IC out from the chip side of the board and then use an appropriate wattage soldering iron, solder sucker and pliers to remove the old solder and pins. Be careful here not to use too much heat, due to the 
age of the boards and the risk of delamination of traces from the PCB.
Then replace the IC with another of the same type. 

73, Dave N4DJS


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