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Solder Problem When Connecting a Decoder Board - Need Help

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Solder Problem When Connecting a Decoder Board - Need Help
Posted by starman on Saturday, May 13, 2017 2:17 PM
I think I may have done something really bad!! 
 
I am installing a decoder in one of my steam engines.  As with most, if not all decoders that do not simply plug in, there are small silver pads (of solder) where you connect the wires from the engine and tender to the decoder.  Everything was connected just fine.  I was very pleased as I had completed a neat solder job.  Then I discovered I needed to connect a second wire to one of the pads.  I got a little sloppy (I think I used too much solder) and the solder ran to the next pad.  I knew the two pads could not be connected so I removed both wires from the pad they were connected to and then attempted to remove the excess solder.  Things did not go well.  Bottom line, when removing the excess solder, I also removed all of the solder that made up the pad.

Is this repairable?  I had no success trying to add solder back to the board.  Have I completed ruined an $80 board?  I sure hope not but what do you think?  If I have ruined the board, any suggestions on how to tell my wife I need a new $80 board?  She is not going to be happy!!

Thanks for your comments.
 
Jack
  • Member since
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  • From: Portland, Oregon
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Posted by Attuvian on Saturday, May 13, 2017 2:31 PM

I wouldn't think you ruined the board unless you also managed to remove the metalic tab underneath the solder that's the foot of the circuit path..  I'd be sure that you are using a low wattage pencil iron for the job.  If so, I'd suggest a very small dab of flux on the pad and then adding the solder back onto the pad.  If you're not an experience solderer, remember to put the hot tip of the iron on the pad first and then immediately nudge your solder up against it as the flux begins to boil away.

 

BTW, what kind of soldering iron were you using?  Hope it wasn't a gun.

Good soldering is kind of an art, but one that's easy to learn - don't be intimidated. Here's some tips:

1) use only the heat that's necessary.  More is NOT better as you can easily fry the board and what's on it,

2) don't hesitate to keep some flux at hand,

3) if the wire is not pre-tinned, I always "tin" it by slightly dipping it in flux and then applying a thin coat of solder to the end, 

4) use only enough solder to make the connection firm, but enough to produce a tapered seat where the end of the wire lays on the pad,

5) don't let the new connection move after you removed the iron's tip.  Your new joint should have a sheen or shine to it.  If it has a "cloudy" or matte-like finish, it's what's called a "cold solder" joint and is likely to give you a troublesome connection or fall off altogether later on.

Enjoy!

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Posted by richg1998 on Saturday, May 13, 2017 2:41 PM

I have used a forty watt soldering pencil with fine conical tip.

My solder station, I now use fifty percent setting with the fine tip.

I use 1/32 inch diameter rosin core solder with a dab or rosin flux on the PC board. If the PC board has been around for sometime, I use a Micro Mark scratch brush to clean the terminal, just to make sure. Light application.

I use a acid brush with alcohol to clean up after. Brushes are cheap by the batch.

I use solder wick or solder sipper to remove solder. Google both.

If you have a magnifying device, check the spot carefully. I use a Optivisor for close up work.

Rich

N

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Posted by starman on Saturday, May 13, 2017 2:44 PM
Thanks, Attuvian, for your reply.  I have done some soldering, but not much since I retired.   I am using a low wattage pencil type iron.  I my case, I got in a hurry and got a little sloppy.  I have been told never to use flux on a board, however, I am going to use a little, as you suggested, to see if I can add back the solder.
 
One piece of good news.  The decoder board was only $33.  It was the sound board that plugs onto the decoder board that cost $80.
 

 

Jack
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Posted by starman on Saturday, May 13, 2017 2:52 PM

Thanks, richg1998, for your reply.  When doing the little soldering I did when working (not a whole lot) I had a solder pullit (I think that is what they were called) avaiable for removing solder.  I don't expect to be removing enough solder to justify a solder pullet, but I will get some solder wick as you suggest.  Any suggestions as to what works well?

Thanks,

Jack

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Posted by Attuvian on Saturday, May 13, 2017 2:57 PM

Rich has good advice.  As for flux on a board, yes, I'd avoid getting it all over the area for sure.  Just the smallest speck on the pad should do but only if solder doesn't seem to be coating.  And one more thing: solder loves the tip of your iron as much as where you want it to go for the connection.  It will tend to collect on the tip with two less than thrilling results: first, a goopy tip that torpedoes your precision and globs up your connection; second, a dirty tip as it sits there between operations and slags up.  Keep a small damp sponge at hand to clean it off.

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Posted by RR_Mel on Saturday, May 13, 2017 3:13 PM

When I was cruising eBay I ran across a cheapo soldering iron with a suction pump for removing solder from PC boards.  It’s far from a $300+ soldering station with suction but it does work pretty good.
 
 
I’ve used it to clean up several Arduino expansion shields and I’ve been pretty happy with the results.
 
US seller too.
 
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
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Posted by rrinker on Saturday, May 13, 2017 3:32 PM

 The braided desoldering wick also works well for removing excess solder.

Excess heat definitely can delaminate the copper from the PC board. If that happens, it's pretty much ruined unless there is another part of the same trace that you can easily reach, and scrape some of the solder mask off to expose the copper.

 Tiny bits of flux (use a toothpick, or the smallest microbrush) apllied to solder pads in close quarters works very well to keep the solder from bridging one pad to the other. The solder is draw to where the flux is. You can, of course, still go overboard and apply too much solder to where the ball gets too big and spreads, but using flux vs not using flux, this point take more solder, so you have a greater leeway before something bad happens. Also you want to use fine wire solder, .015 or .020. The .032 commonly found at Radio Shack and similar is too big for fine decoder work.

                    --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richg1998 on Saturday, May 13, 2017 3:34 PM

I bought my spring loaded solder sipper, maybe a pullet/r, many years ago.

I used the shield RG174 coax to make solder wick when I was a NASA contractor in the 1970's. We used a lot of that coax. I would pull the shield and dip into liquid rosin flux. How solder wick is made I guess. Let it dry and roll it up in tiny roll. I did a lot of home projects over the years. Been soldering since 1953.

Amazon sells it. Include it with a larger order.

Maybe check online suppliers.Jameco Electronics is a good online supplier.

I just checked both. They have it.

The wick was better than the spring loaded device. I use to have one that was just a rubber bulb. Squezze, put at molten solder and release. Did ok.

Rich

N

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Posted by rrinker on Saturday, May 13, 2017 3:51 PM

 Yes, that is how the wick is made, it's flux coated which helps draw the solder into the braided copper. Making your own...hmm, I'm pretty cheap that way, and I DO have access to about 1/4 spool of coax that will never get used (it's not 50 ohm, it's old 62 ohm Arcnet), the wuestion is, does my cheapness go so far as to go to the effort of stripping all that coax and coating it in flux (I have more than I need, I should have listened when the web site said that you can easily add some DI water to the paste if you need gel or liquid, since it's water soluable - so I haven't even opend the gel, I use only the paste).

                   --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richhotrain on Saturday, May 13, 2017 4:18 PM

starman
If I have ruined the board, any suggestions on how to tell my wife I need a new $80 board?  She is not going to be happy!!
 

Good advice so far, but no one has dared to answer your most critical question.
 
You mentioned elsewhere on this thread that you are now retired, but you failed to completely develop your post-retirement strategy, and that is to maintain a secret slush fund away from the prying eyes of the wife. Now, the only thing worse than possibly replacing a failed decoder is the need to go begging for the money necessary to replace it.
 
Act now, while there is still time, and create that secret slush fund!
 
Rich

Alton Junction

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Posted by richg1998 on Saturday, May 13, 2017 4:24 PM

You can fix this with small diameter bare wire and careful soldering. Definitely use an optivisor. I have done this a few times over the years. Maybe a dab of Goo to hold everything in place.

I use RG174 coax, small diameter stuff as all the equipment NASA used in the range control center where I worked used this coax. 1970’s. Vacuum tube equipment. An example, dual triode vacuum tubes for a 1k shift register. 

Vacuum tube digital analog equipment No sign wave was a zero. A sine wave was a one.

Where I lived was thirty miles from an electronic supply company. Amateur radio, shortwave magazine suggestions

No Internet either.

Rich

N

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Posted by Attuvian on Saturday, May 13, 2017 6:56 PM

Wow! Caveman stuff, Rich.

I worked at a firm that created sonobouys for the Navy.  Did my thing building test equipment in the proto shop.  Nobody but nobody used the spring-loaded solder "pullits".  It was the rubber syringe with the heat resistant removeable tip that ruled the day.  The only thing a guy didn't have enough of was hands and fingers.  That's why some smart guy developed CLAMPS and CLIPS to hold the work while we did the important operations.  Ah, the aroma of flux and rosin vapors . . . .  Carcinogenic in huge doses to rats in California, no doubt!

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Posted by RR_Mel on Saturday, May 13, 2017 7:09 PM

Attuvian

Wow! Caveman stuff, Rich.

 

Watch it, this caveman got his start in electronics before the transistor was born.  Without the cavemen there wouldn’t have been a transistor. WinkWink
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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  • From: Reading, PA
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Posted by rrinker on Saturday, May 13, 2017 7:23 PM

 You cavemen used tubes because it meant you could listen to the radio AND heat your home with just one device. Big Smile

                     --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by RR_Mel on Saturday, May 13, 2017 7:57 PM

I burnt my fingers many times pulling 80s and the newer 5Y3s.
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
  • Member since
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  • From: Portland, Oregon
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Posted by Attuvian on Saturday, May 13, 2017 9:45 PM

Hey, Mel - I'm waaay past watching it.  Besides, I'm older than you imagine.  I remember replacing peanut tubes in Navy avaition comm gear in the 60s and having NYC steamers drop conders on my head as I watched from beside the tracks a dozen years befor that.  Mom had no idea how close I was to the tracks.  Those were the days when your parents sent you out to play and saved their anxieties for your teen years!

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Posted by rrinker on Saturday, May 13, 2017 9:46 PM

 Thoough I did make a HUGE blunder cleaning out my Moom's house. I threw away the Eico stereo systrem my Dad built from kits in the late 50's/early 60's. FM receiver, preamp, and amp, all tubes. I have since found out that just the preamp, in non-working condition (as this one was) sell for $400-$500 on ebay. NON WORKING!. The reciever goes for $300, and last time I used it in the early 80's, it was working, including the magic eye tuner.

 Just think of the trains I could have bought...

                        --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by tstage on Sunday, May 14, 2017 12:08 AM

rrinker

Excess heat definitely can delaminate the copper from the PC board. If that happens, it's pretty much ruined unless there is another part of the same trace that you can easily reach, and scrape some of the solder mask off to expose the copper.

starman,

If you did delaminate the soldering pad on the decoder board, as it sounds like you did, use a used X-acto blade to gently scrape the solder mask off the trace that went to that pad to expose the copper, as Randy suggested.  You can then solder a wire to the exposed trace.  If you get good contact to the trace with the wire, apply a dab of two-part epoxy to protect the trace and wire from pulling up.  A hot-glue gun also works quite well to accomplish the same thing.

Whenever soldering to a PCB:

  1. Tin your solering pad
  2. Strip & tin your wire
  3. Apply a small amount of flux paste to that pad
  4. Solder your wire to the pad

When applying the soldering iron to the tinned soldering pad & wire, only leave the iron on long enough to liquidify the solder then quickly remove it; at the same time while leaving the wire in place while the solder cools.  That way you will eliminate the possibility of "cooking" your PCB pads.

Tom

http://www.newyorkcentralmodeling.com

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by Stevert on Sunday, May 14, 2017 7:56 AM

I'm surprised that nobody so far has suggested this 'fix" for your decoder - Check it's warranty.

Some manufacturers (Digitrax for sure, I think TCS, and maybe others) offer a "goof-proof" warranty and will replace your decoder within the warranty period no matter what caused it's demise.

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Posted by starman on Tuesday, May 16, 2017 7:38 PM

Stevert

I'm surprised that nobody so far has suggested this 'fix" for your decoder - Check it's warranty.

Some manufacturers (Digitrax for sure, I think TCS, and maybe others) offer a "goof-proof" warranty and will replace your decoder within the warranty period no matter what caused it's demise.

 

Great suggestion!  The decoder is from Train Control Systems (TCS).  I contacted them and told them what I did.  They replied, saying, they have a "Goof Proof" warranty and would repair or replace, at their discretion, my decoder.  I did not know about this warranty when I purchased the decoder.  What a great warranty.  Train Control Systems (TCS) is treating me right!!

 

Jack

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