IC Sockets

[Jim KO5V]

I've built many electronics projects over the years, and most of them have actually worked. However, I am an ME, so my actual knowledge of electronics is a bit spotty, and most of my ham radio experience is not with TTL level stuff.

I would like to use IC sockets on my current clock project, but this design does not call for using them everywhere. I've had to unsolder a few ICs in the past, and the PC boards have almost always suffered, sometimes requiring some really ugly repairs.

So, is there a reason other than saving a few parts for not using the IC sockets - like added paths for noise, or??

Thanks in advance. I hope this isn't too stupid a question!  Jim

[Mac Doktor]

On Feb 18, 2023, at 6:26 PM, Jim KO5V <jr...@earthlink.net> wrote:

So, is there a reason other than saving a few parts for not using the IC sockets - like added paths for noise, or??

If you're going to use sockets you want reliable retention. Chips can work loose over time especially with lots of thermal cycling. Double-wipe sockets are the best if you want something to be as disaster-proof as possible. I've never used anything else.

Machined collect sockets have weaker retention but are desirable if you're going to be swapping ICs in and out during the development phase or installing updates in the field. In the old days this would have been something like an EPROM with firmware on it.

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com

Q: Should car stereo speakers be pointed to the rear for more thrust or up for more traction?

A. On long trips, the 20- to 30% improvement in gas mileage you might get with speakers pointing to the rear is certainly worthwhile. On the other hand, if you drive on snow or ice, the extra traction of speakers pointing upward gives you added control.

Don Lancaster

[Moses]

Jim,

I agree with Mac, one downside to sockets is some tend to come loose. It is mechanical retention after all, and at times with questionable quality sockets. Not usually a problem with stationary electronics, something in a high vibration environment like a vehicle will give you more problems. Corrosion is another 'issue'.. but if it's that bad you should be coating your boards anyway. Vintage stuff tends to be problematic at times, ICs that have been sitting in a socket for 40 years may not be making the best contact.

Most low frequency signals, KHz, a few MHz for example, should be fine with a socket. Sensitive feedback circuits, for example on a DC-DC switching IC, I would not put in a socket.

I usually use sockets on a prototype where I think I may need to swap parts, or the likelihood of destroying an IC during testing is high. Otherwise modern stuff is so reliable these days, if it's a production PCB or part that I know I'm not going to mess with, I won't use a socket. Modern integrated circuits, if used within their design limits, will last decades.

I've been doing this for a while, and some stuff is just difficult to desolder without damage, that's how you learn PCB trace repair! :)

Regards,

-Moses

[Charles MacDonald]

> something in a high vibration environment like a vehicle will give you
> more problems. Corrosion is another 'issue'.. but if it's that bad you
> should be coating your boards anyway.

back in the 70s I delt with Apple ][ Computers that used socket-ed DIP
ICs problems Noted:

bad contact - corrosion.
loose IC due to vibration.
they went for Premium AMP brand sockets to get better retention and some
of the ICs left the factory with one or more the pins bent under. this
worked at first, BUT made for Flaky INTERMITTENT contacts.

Also the socket will have more capacitance then just a plain PC Board,
which might round off your signal edges. I think we even had one board
where the larger area of the contacts caused a solder bridge, and
pulling the socket was more difficult than just pulling an IC would have
been.

--
Charles MacDonald VA3CPY Stittsville Ontario
cm...@zeusprune.ca Just Beyond the Fringe
No Microsoft Products were used in sending this e-mail.

[gregebert]

Dont use IC sockets; they are not necessary.

If the circuit is properly designed, meaning that all IC datasheet parameters are met, you should never see an IC fail. I've built many nixie clocks, all of which I designed, and I've never had an IC fail on it's own. The first failure I've had was a few weeks ago, caused by ESD (my fault) on a Raspberry Pi, so technically not one of my designs.

IC's are actually easy to remove without damaging the PCB, though you will likely destroy the IC in the process. For thru-hole IC, flow fresh solder into each pin, and while it's still molten, use a vacuum desoldering tool like the Edsyn Soldapullt (see below). I've been using mine for ~40 years now, and it still works great. Once the pin is sucked-out, wiggle it with the soldering iron and it should be free. Once all pins are cleared, you should be able to gently wiggle the IC out with your fingers. If not, snip the stuck pins off the IC with fine clippers, then use tweezers to remove the pin while heating it. After all pins are clear, mop-up with some solder wick, then clean with 90% isopropyl alcohol. PCB should be just-like-new.

SMT parts need careful heating with a hot-air reflow tool, and you should be able to gently lift it with tweezers, though some pins will get bent and most likely the IC has been thermally overstressed, so toss it away. Clean-up is same as above.

Lastly, I never breadboard a design. PCBs are easy and cheap to have fabbed, and have far superior quality. If you mangle a board with debugging, build another. But if you do proper simulation beforehand designing the PCB, you wont need to do any debugging.

https://www.edsyn.com/product/DS017.html

[Jim Faulkner]

Thanks to everyone who replied to my question. The consensus is that I should probably not use sockets unless the design calls for them, so that's what I will do.

 

As someone mentioned, once I realized that I had nothing to lose by destroying the bad part and removing it in pieces, I've caused little or no damage. However, some of

the boards that I have messed up seemed too delicate (or cheap) because the traces lifted very easily. I've had a Soldapullt for many years, and it is one of my most useful tools.

 

Jim