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DIP Sockets - Which should I order?

Chuckster_in_Jax

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Feb 28, 2006
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Jacksonville, Florida
I'm getting ready to order some 14 pin DIP sockets. Places like Digikey and Mouser have a wide range of types with prices from $0.16 to over $2 a piece. For our use in vintage computers, what is the break even point for performance vs. price.

I would like to buy the machine pin style but don't know if it's worth paying the extra bucks over a dual wipe style.

Gold contacts over Bronze/Beryllium or tin? If gold, would 15u plating be OK or is the heavier 20u or 30u worth the extra bucks?

Also, I have heard that low-profile aren't as good as the standard height. Is there any truth to that?

Chuck
 
I can only speak from 35+ years experience.

Go with the machine-pin--you won't regret it. Prowl around the web a bit and you can get some very good deals. Also, you can get the strip style from various Chinese vendors on ebay (search on "round female header"). Low-profile machine-pin sockets are the rule--I've never seen a standard-height one.

For most ICs, tinplate is okay--a machine-pin socket makes a gas-tight connection. If you're using gold-pin ICs, then use gold. There are other exotic possibilities, such as built-in bypass caps (corner-to-corner), but they're generally not worth the cost and murder to repair.
 
I second machine pin sockets. I try to use them in all of my projects over the dual leaf sockets. Dual leaf sockets also tend to cause chip creep a lot faster than machine pin sockets.
 
I'll definitely go with the low profile, machine pin. I saw those with the built in capacitor and figured they could be a real problem down the road so I'll leave them alone.

Thanks Guys!

Chuck
 
Last time I needed DIP sockets (when I fixed the RAM on my Atari 65xe) I just purchased the cheap ones. Looking at the reciept it was 50 pcs. 16 pin DIP IC Sockets Adaptor Solder Type for $6.30 shipped from Thailand. Thaishopetc was the seller on ebay.

http://cgi.ebay.com/34-pcs-14-pin-DIP-IC-Sockets-Adaptor-Solder-Type-/390108715909 $5.49 for 34 pcs shipped.

I would buy better sockets for rare or prized equipment, but for common stuff I just get the cheapest. Its not like atari even bothered to use a socket for their ram to save a few cents, and if a chip blows next time the repair will be much easier.
 
Take a look at eBay 320543344865. For $6 shipped, you get 10 strips of 40 machine pin, snap-off type socket headers. That's 400 pins, which amounts to 25 16-pin DIP sockets. For $40 shipped, you can get 4000 pins, which ought to keep you in sockets for the remainder of the year, at least. For about $5 shipped, you can get 200 10-micron gold-plated pins.

I like these because I don't have to keep an inventory of various socket sizes--and if I ever get some of the oddball DIP sizes, such as 22-pin 0.400", I don't have to go scrambling for an obscure part.
 
You're welcome. If you use those little PCB SMT adapters, look at eBay's "round male headers" You solder them into the holes in the QFP adapter and then you can plug the whole affair into regular machine-pin socket strips. Works much better than the regular square-pin headers.
 
I never use machine pin sockets. They have a nasty shoulder on the pin that traps solder on top of the upper pad. If you ever break off a pin in the socket and have to desolder it you must take extra care to desolder the top completely or you WILL pull the pad and trace off the top of the board.

The kits I sell on my website all contain dual wipe sockets and I've never had any issues with repairs I've made over the years with them.
 
I never use machine pin sockets. They have a nasty shoulder on the pin that traps solder on top of the upper pad. If you ever break off a pin in the socket and have to desolder it you must take extra care to desolder the top completely or you WILL pull the pad and trace off the top of the board..

I've never had any issues like that--and I've even salvaged sockets from PCBs without damaging the traces. But everyone's different, I guess.
 
Hi
I've never had problems. Just yesterday, I soldered three sockets
on the wrong side of my protoboard. I unsoldered them with no
more trouble then normal. No pads lifted.
My vote is for machine pin sockets.
Dwight
 
Hi
I've never had problems. Just yesterday, I soldered three sockets
on the wrong side of my protoboard. I unsoldered them with no
more trouble then normal. No pads lifted.
My vote is for machine pin sockets.
Dwight

Hi

They are both fine on new stuff projects etc, but on old pcb's with very thin traces that lift easy I would go with the dual wipe sockets

Mutt
 
There are a multitude of things to consider.

One primary one is, what is the shape of the pins you plan to insert into the socket ?

Thin flat pins, characteristic of IC's, are better off in a dual wipe socket than an round machine pin one.

However, if you have items such as IC adapters, with round Gold pins in the diameter range of 0.45 to 0.55mm, these are not good in a dual wipe socket and are excellent in a machine pin socket.

Then there is the issue of repair-ability.

One great advantage of the modern dual wipe socket is, that if one of its claw structures gets damaged, you do not have to replace the whole socket. You can withdraw one claw arrangement at a time from the top, and replace it if you wish.

On the other hand, you cannot do that with a machine pin socket, because of the way is pins are molded into the plastic. And the plastic of the machine pin socket is too brittle to cut, without bending the pins and risking track and pad damage to do a one pin at a time extraction.

In addition, the cross sectional area of the machine pin socket pin, can be a significant proportion of the hole size in the pcb, making solder sucking more difficult, not always, but sometimes, depending on the hole size , and as noted the shoulder on the machine pin socket, even after solder sucking, can stick to the pad around the pcb hole, risking lifting off pads/tracks when the socket is removed.

So, on all the factors, checks and balances, the "safer" option is the dual wipe socket especially for flat pin device projecting into them. This provides the better option for future repairs too. But, still I go for round pin socket if the pins I'm putting into them are round in cross section and no bigger than 0.45 to 0.55mm in diameter.

And still there is something else:

Any of the comparisons between the merits of both styles of the socket designs are pointless, if the sockets are poor quality cheap knock offs. Often this is because the Metallurgy is not ideal and the material not springy enough. So after a few insertions and removals of different IC's the claw tension is lost and the spacing between the claws permanently stretched because they don't go back to their original geometry after being opened up a few times by whatever was put in the socket.

This is why you should never put any object into an IC socket (that is normally receiving an IC pin of about 0.3mm in thickness), like some adapters, that is bigger than about 0.45mm diameter, because it will stretch the claws apart, permanently, especially in cheap sockets, then making it unreliable for an IC put back in the socket later. But, oddly there are many adapters for "this and that" out there with very fat pins, that damage IC sockets, even good quality ones, from the perspective of putting an IC back into them later.

Of course it would be fair to say, if you only ever put an IC into a socket once, never had to remove it, and never had to replace the socket, then the difference between the two types of sockets diminishes to near zero, and in that case I would use the machine pin type. And taking that further, if the pcb is single sided, without plated through holes, I would use the machine pin type too, because they are effortless to un-solder in that case.
 
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Of course it would be fair to say, if you only ever put an IC into a socket once, never had to remove it, and never had to replace the socket, then the difference between the two types of sockets diminishes to near zero, and in that case I would use the machine pin type. And taking that further, if the pcb is single sided, without plated through holes, I would use the machine pin type too, because they are effortless to un-solder in that case.
Good summary. As noted earlier in this thread the machine pin sockets force a four-point oxidation-resistant contact, which is very good for future reliability (including vibration resistance). However the operative term there is _force_ so one needs to use additional care when inserting ICs as the required force is more likely to bend pins than with the simple "slip and slide" dual-leaf sockets. However once the IC is properly inserted the connection is essentially as good as soldering directly.
 
If a pin is taken from a defunct IC and soldered to a small wire handle, you can use it to examine individual socket claws on vintage computer boards by feeling the spring tension.

When you put an IC into a socket, you can get a "global feeling" about the frictional forces from all of the claws in the socket. But, if you examine them one by one, you will find the occasional awful surprise where the tension is insignificant.

Often, because the IC pins are not formed well, so that they match the exact position of the socket's entry point, and they are splayed out a little, even if the socket claw is defective they can still "make contact" but it is unreliable.

In any case, the examination of a used IC socket requires that every claw is checked separately, or the examination is incomplete.

No IC socket, in the long run, is as good as soldering directly. This is because the sockets claws and pins are dissimilar metals and often as the years go by corrosion appears in the zones of contact. This is particularly evident with TI sockets that grab the pin over a small area across the longer axis. If you inspect the IC pins under magnification, there is always a grey or a black line of oxide (oxides are insulators) where the two metal types were in contact. It must be scraped away. Mind you it does seem to take more than 3 or 4 decades for it to appear.
 
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My experience with machine/round pin sockets seems to be the opposite of some. I don't understand the attraction. Every time I've tried to use them (repairing C64's, etc) the chips pop out of the sockets on me, or don't make good connection. Even worse using strips, since they can be different widths then, and wiggle around on the board and break the connections.

When I look up the use case for them, they seem to be made for cable harnesses, not DIP chips.

But, I don't claim to be an "engineer". Just my experience doing repairs for 30+ years.

I just use dual-wipes, and NEVER plug square pin strips into them, because it ruins them. :)
 
I'm firmly in the machine pin camp.
But this is very important: Only use good sockets. I only buy Mill-Max. (yeah expensive)
I've never had to replace one. I've never had an IC work loose.

I agree. Never plug a square pin into an IC socket.
 
I'm firmly in the machine pin camp.
But this is very important: Only use good sockets. I only buy Mill-Max. (yeah expensive)
I've never had to replace one. I've never had an IC work loose.

I agree. Never plug a square pin into an IC socket.
Its not so much a rule about square pins, or rectangular ones for that matter. It is pin size.

You will find that if you measure IC pins they are only about 0.25 to 0.3mm on their thin axis and about 0.45 to 0.5mm thick on the wider axis.

If you plug these into a dual wipe socket, the spring leaflets at worst are only pushed apart 0.3mm. Even one of the thinnest Millmax Gold round pins used on adapter boards is around 0.45 mm in diameter. So putting this round pin into a dual wipe socket will force the connections apart significantly more than the IC pin. If the contact material is not good quality Beryllium Copper it will deform and not spring back to its original geometry after the 0.45mm pin is removed.Then it will make a poor contact with the IC.

Looking at round pin sockets, typically the actual pins to pass into the pcb on these are 0.5mm diameter. Some people to store or ship these sockets, push the sockets pins of one socket into the holes of the other. This stretches the contacts. If you do this as an experiment you will find that it then makes the socket useless for an IC pin. And, if you probe the socket tension with a 0.45mm round Millmax pin, it has lost significant friction if you compare it with an unused socket. Many round pin sockets get damaged like this by mishandling, or people shipping them and thinking stacking them together is the safest way of shipping. So if you have machine pin sockets, where IC's fall out of them, this is the cause. (PS if you do this experiment make sure you throw the socket in the bin afterwards or you might end up using it later). Even at a local store where I was buying sockets, the guy behind the counter startet stacking them together, he ruined a couple before I stopped him.He didn't believe me and the sockets went back into stock.

The moral of the story is never put anything greater than 0.3mm thick into any IC socket (In other words nothing other other than an actual IC pin or a pin of identical geometry), regardless round or square shape, if you want to be sure you can use the socket again reliably for an actual IC. This is also why a test pin for the socket tension, should only be made from a defunct IC pin.

Of course if typical header pins are pushed into them which are usually over 0.5 to 0.7 mm or bigger, the socket is ruined for an IC, even a good quality socket can't return to being useful for an IC.
 
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I buy the cheapest machine pin sockets in can find on aliexpress or eBay. There are at least three failure modes.

1) bent pins. They stuff them all haphazardly into a baggie and some pins will bend. They’re made of brittle metal and there’s a possibility the pin will snap when you straighten it.

2) pins with missing contacts inside of them. Look closely before soldering. More than once I’ve missed this — with the ”guts” missing it wont make electrical contact to the ic pins. You won’t notice it once the ic is installed, and you’ll waste debugging time trying to figure out why something isn’t working, and it turns out to be the damn crappy socket,

3) pins that won’t release. This is a new one for 2023. Sometimes I try to pull an ic and one leg of the ic gets “stuck” and I have to yank on it hard. I haven’t ruined an ic or a socket… yet. This is by far the most disconcerting, as you could end up damaging a valuable vintage ic.

I budget about 5-10% of the sockets to be junk.

given all that, is it worth it to buy the cheap aliexpress sockets? I dunno, If I h ad to bill out troubleshooting time, it might well not be worth it. It’s just a hobby, and I do go through a ton of sockets.
 
I buy the cheapest machine pin sockets in can find on aliexpress or eBay. There are at least three failure modes.

1) bent pins. They stuff them all haphazardly into a baggie and some pins will bend. They’re made of brittle metal and there’s a possibility the pin will snap when you straighten it.

2) pins with missing contacts inside of them. Look closely before soldering. More than once I’ve missed this — with the ”guts” missing it wont make electrical contact to the ic pins. You won’t notice it once the ic is installed, and you’ll waste debugging time trying to figure out why something isn’t working, and it turns out to be the damn crappy socket,

3) pins that won’t release. This is a new one for 2023. Sometimes I try to pull an ic and one leg of the ic gets “stuck” and I have to yank on it hard. I haven’t ruined an ic or a socket… yet. This is by far the most disconcerting, as you could end up damaging a valuable vintage ic.

I budget about 5-10% of the sockets to be junk.

given all that, is it worth it to buy the cheap aliexpress sockets? I dunno, If I h ad to bill out troubleshooting time, it might well not be worth it. It’s just a hobby, and I do go through a ton of sockets.

I have experienced that stuck pin effect too. One thing that can help is to pre lubricate the sockets, especially if the IC is to be taken out or exchanged a few times. Inox MX-3 works well for this as it is a high purity oil.
 
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