Protoboard IC replacement

Thread Starter

wayneh

Joined Sep 9, 2010
17,152
I'm finally coming to the end of a long build, long because I decided to do 3 in parallel. It's certainly faster than doing one at a time but it's still a lot of work.

I powered up the 3 units today and not one of them works. What a gut-wrenching feeling! After a full review, I realized the problem was ... me, of course. I had ordered the wrong parts almost 5 years ago: CD40174BE (hex flip-flop) instead of CD4017BE (decade counter). I never realized it until today. Sigh.

Now I need to remove the 16-pin DIPs and replace them. What's the easiest method? I read a trick somewhere to cut the old IC out with a Dremel. Then it's relatively easy to pull the old pins one at a time. That sounds better to me than trying to solder-braid the solder out while the IC is in place. I've used solder braid a time or two and I always struggle with it.

Ideas?

This might be a good topic to include in @Wendy 's protoboard cookbook – how to fix them.
 

dendad

Joined Feb 20, 2016
3,835
I use a sharp pair of cutters and snip each pin one at a time,
cutters.jpg
then remove the pins.
A Dremel sounds a bit to easy to cause damage to me.
After that, solder braid to clean out the holes.
A good vacuum solder sucker tool works well, but they are quite expensive.
The spring operated versions are ok if used carefully, but can damage the board with the mechanical shock.
As to the wrong part numbers, been there, done that too! VERY annoying when it is discovered.
 

dl324

Joined Mar 30, 2015
12,871
What's the easiest method?
I'd use a solder sucker. Did it hundreds/thousands of times when I was a technician troubleshooting refrigerator sized computers using SSI/MSI IC's. That was a vacuum pump operated setup and quite effective. At home, I use a spring loaded solder sucker.

I avoid the problem in my designs by installing all IC's in sockets. I sometimes use machined pin sockets for transistors.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,152
I do have a vacuum pump and a trap. I'd need to fashion the tip end. Hmmm.... I wonder if a glass pipette would work. I think I have some I could try.
 

dendad

Joined Feb 20, 2016
3,835
My solder sucker gun has a hard clear plastic solder collection cylinder and a felt like filter on the end, followed by a smaller filter that is in fact a cigarette filter. These are available where roll your own cigarette products are found.
A glass tube would work well I think, or a small glass jar. But make sure a good filter is included to keep the fumes out of the pump.
 

dl324

Joined Mar 30, 2015
12,871
I wonder if a glass pipette would work. I think I have some I could try.
The tip should be somewhat heatproof and flexible so you can get a good seal over the melted solder.

If this was a vacuum desolder with a heated tip, hard is fine. But every vacuum remover I've used had a pliable tip.

EDIT: Aside from my vacuum desoldering tool on my hot air station.
 
Last edited:

dendad

Joined Feb 20, 2016
3,835
This is what I use...
DenonSolderSucker.jpg
DenonSolderSucker2.jpg
The "tips" are available in different sizes...
DenonSolderSucker3.jpg
It is a self contained unit and works very well, at least it does with regular cleaning.

I also purchased a second hand unit that has an external pump, but that one I do not use as it needs some work to get it to good order.
 

Teljkon

Joined Jan 24, 2019
184
Maybe I’ll look to buy a tip but fashion my own vacuum.
sounds like a whole new project. watch out for project Itus. I find the hooked tip for my soldering iron makes working with braid fairly easy. This probably goes with out saying but flux also helps. Never know what step some one isn't using. Might want to hit up the youtube videos for board repair guys like Louis Rossman for technique. Those guys are cleaning solder up every day even if it isn't through hole.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,152
Well I decided to splurge a little and not get the cheapest sucker I could find. Nothing as fancy as @dendad 's or @MaxHeadRoom 's, but many positive reviews. Arrives today. Using one of these should be a useful addition to my skillset. I'll probably wonder why I didn't do this a long time ago.

I believe the Engineer SS-02 is identical to the Vampire VST-001, which I suspect is a rebranded version.


Screen Shot 2021-02-23 at 12.03.35 PM.png
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,152
At work, I have two of this series of tools:
...
They are almost indecently expensive, but do the job really nicely when it comes to 0.65 and 0.50 mm. pitch SMD ICs.
Thankfully, I'm still in the thru-hole era. I'd have to be desperate to take on any SMD project. Maybe someday. I'd need a nice microscope to even get started.
 

AlbertHall

Joined Jun 4, 2014
11,305
I used to put a piece of silicon tubing over the end of my spring loaded solder sucker. It gives a good seal and is also more gentle on the tracks.
But I'm rich now so I can spring for the cost of desolder braid.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,152
It took a little practice to get used to it but the solder sucker works great. It's a nice solid tool. On an unobstructed pin, I can get a hole showing daylight to the other side in one shot. It's tougher when there are obstacles to work around but it's not too bad.

Trouble is, I can't get that last bit of solder that capillaries in between the leg of the IC and the wall of the thru-hole. I've tried repeat sucks and also braid. The braid gets a little solder that the sucker leaves behind but I'm clumsy with it.

Out of frustration I resorted to my old method of using a chip puller to apply constant pulling force while touching all the pins in succession. Even that isn't working for me. I've used a small screwdriver to push the legs away from the hole walls. Might have broken a couple free. All in all, I think I may have half the pins truly free but half not.

Cutting the damn thing out is looking like a better option all the time. But I though I would take a break and let the frustration pass over first.

Advice welcome!
 

metermannd

Joined Oct 25, 2020
189
I use a plunger-type solder extractor and it works GREAT.
I can't seem to find it online though. Below is a link to a picture of the style I use at work. A pass around the leads, then I use a pick to test and break free the leads from the remaining solder, sometimes I have to use the iron again to put a bit of heat and side pressure on the last few pins to coax them free.

Picture of Solder Extractor.
 

Yaakov

Joined Jan 27, 2019
3,152
I use a plunger-type solder extractor and it works GREAT.
I can't seem to find it online though. Below is a link to a picture of the style I use at work. A pass around the leads, then I use a pick to test and break free the leads from the remaining solder, sometimes I have to use the iron again to put a bit of heat and side pressure on the last few pins to coax them free.

Picture of Solder Extractor.
That is a copy of a "Soldapult". I have an ESD version. The real ones are better than the copies.
 
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