Computer Mouse Solder Problem

Thread Starter

zod1aq

Joined Apr 3, 2021
7
So I had my first soldering experience on my second computer mouse, idea was just to put in new microswitches. I began to do with my old thick soldering iron and now it looks like I applied too much heat and my solder pads GONE. I bought myself a new better soldering iron, but havent seen any success. Solder wire did not want to flow through hole even though it had a lead. Ive asked people on other electronic-related website, they told me I should scrap off some plastic mask to find a trace and then solder to it, I did so and I still dont see any traces, but there is a visible layer of copper and something that looked like a little metal wire. I have tried to scrap off other side of the PCB, but there was just solid layer of copper. My soldering iron tip isnt oxidized, I use brass sponge after every use now. Please tell me there is a second chance for me in this.
 

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dl324

Joined Mar 30, 2015
12,783
Welcome to AAC!

Clean up the board and post some well focused pictures of the problem areas. Put the board on something and then take close ups.

Solder won't flow through a hole unless it's plated.

You're probably going to end up tossing the mouse. Your soldering skills aren't very good (it doesn't look like any of your joints were done correctly) and you don't acquire good skills in your first attempt so you shouldn't start with something important.
 

Thread Starter

zod1aq

Joined Apr 3, 2021
7
Welcome to AAC!

Clean up the board and post some well focused pictures of the problem areas. Put the board on something and then take close ups.

Solder won't flow through a hole unless it's plated.

You're probably going to end up tossing the mouse. Your soldering skills aren't very good (it doesn't look like any of your joints were done correctly) and you don't acquire good skills in your first attempt so you shouldn't start with something important.
Havent found any background for the pics, but I hope you are able to see it.photo_2021-04-03_18-54-15.jpgphoto_2021-04-03_18-54-13.jpgphoto_2021-04-03_18-54-11.jpgphoto_2021-04-03_18-54-07.jpg
 

dl324

Joined Mar 30, 2015
12,783
I can only make out a trace that connected to the middle terminal of the left (from the bottom) switch. Going to need pictures with better focus to make out any other traces. It would be helpful if you marked them in the pictures.

What you need to do is identify traces going to all of the switch terminals. Hopefully the board isn't more than two layers.

What type of solder are you using (diameter and flux info). What size and shape is the soldering iron tip? Do you have extra flux that you can apply? Flux will help transfer heat and make the solder flow better.

None of your joints looked like the solder flowed correctly. You need to heat the things to be soldered and have the parts to be soldered melt the solder. It looked like you were touching the solder to the iron and getting blobs of solder. A proper solder joint will form a metallic bond with the parts being joined. Joints without pads are never going to look good.
 

Thread Starter

zod1aq

Joined Apr 3, 2021
7
I can only make out a trace that connected to the middle terminal of the left (from the bottom) switch. Going to need pictures with better focus to make out any other traces. It would be helpful if you marked them in the pictures.

What you need to do is identify traces going to all of the switch terminals. Hopefully the board isn't more than two layers.

What type of solder are you using (diameter and flux info). What size and shape is the soldering iron tip? Do you have extra flux that you can apply? Flux will help transfer heat and make the solder flow better.

None of your joints looked like the solder flowed correctly. You need to heat the things to be soldered and have the parts to be soldered melt the solder. It looked like you were touching the solder to the iron and getting blobs of solder. A proper solder joint will form a metallic bond with the parts being joined. Joints without pads are never going to look good.
Looks like there is only two visible traces, middle one on the left click and middle one on the right click and they are located on different sides of the pcb. (Photos below)
My solder wire is 0.031 inch/0.8 mm with 2% lead rosin core containing 60% Sn and 40% Pb.
Soldering iron tip I am working with is pretty small "I" if it says something for you. I can get its measurements if need.
 

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Thread Starter

zod1aq

Joined Apr 3, 2021
7
I have scraped some coating off near the second trace path and I all see is some copper, nothing that might look like trace.photo_2021-04-03_22-14-56.jpg
 

dl324

Joined Mar 30, 2015
12,783
Lightened, cropped images:
clipimage.jpgclipimage.jpg
Looks like there is only two visible traces, middle one on the left click and middle one on the right click and they are located on different sides of the pcb.
It's likely that the switches are just switching ground, so you'll need to determine which two contacts were being used and reconnect them using wire jumpers.
Soldering iron tip I am working with is pretty small "I" if it says something for you.
I think what you're describing is a screwdriver tip. If you're not experienced, you should use a small tip. I've been soldering for 40+ years and use a 1/32" conical tip 700F for most of my soldering (tip diameter is as thick as the solder you're using):
clipimage.jpg
 

Thread Starter

zod1aq

Joined Apr 3, 2021
7
It's likely that the switches are just switching ground, so you'll need to determine which two contacts were being used and reconnect them using wire jumpers.
Are there any video examples of that process on the Internet? Because I have no clue how it would look. Also I would like to know how "contacts" look.
 

dl324

Joined Mar 30, 2015
12,783
Are there any video examples of that process on the Internet? Because I have no clue how it would look.
You'll need some small gauge wire. I'd recommend #30 solid. If you use Kynar wire that's used for wire wrap, it will be silver plated. If the length of the wire is short and there's no chance for the wire to short something, you can use bare wire.

Soldering to the switch terminal will be the easiest. Wrap the wire around the terminal; through the hole if one is present. Apply heat to the wire and terminal simultaneously. When the joint has heated enough to melt the solder (test by touching the joint), apply the solder to a point opposite of the tip. If you apply some extra flux, that will help with heat transfer from the tip to the components. A small blob of solder on the tip of your iron will do the same thing.
Also I would like to know how "contacts" look.
With leaded solder, the joint should look shiny and shouldn't look like a "blob":
1617482566055.png
In a good joint, the solder bonds with the things being soldered.

The joint between the wire and trace should be fairly flat. These joints are okay, but the flux should have been cleaned up. The person who made them wasn't very adept at soldering to a "largish" (e.g. larger than a pad) surface.
1617482841641.png
In your case, you want to run the wire parallel to the trace. Some flux paste or liquid will clean any oxidation from the trace. You need to use a blade to scrape away the solder mask.
 

twohats

Joined Oct 28, 2015
202
@ Delta prime.
I was joking about the Palm reading.
Are you a mathematician? Crystal ball and some serious formulae.
 

Thread Starter

zod1aq

Joined Apr 3, 2021
7
You'll need some small gauge wire. I'd recommend #30 solid. If you use Kynar wire that's used for wire wrap, it will be silver plated. If the length of the wire is short and there's no chance for the wire to short something, you can use bare wire.

Soldering to the switch terminal will be the easiest. Wrap the wire around the terminal; through the hole if one is present. Apply heat to the wire and terminal simultaneously. When the joint has heated enough to melt the solder (test by touching the joint), apply the solder to a point opposite of the tip. If you apply some extra flux, that will help with heat transfer from the tip to the components. A small blob of solder on the tip of your iron will do the same thing.
With leaded solder, the joint should look shiny and shouldn't look like a "blob":
View attachment 234417
In a good joint, the solder bonds with the things being soldered.

The joint between the wire and trace should be fairly flat. These joints are okay, but the flux should have been cleaned up. The person who made them wasn't very adept at soldering to a "largish" (e.g. larger than a pad) surface.
View attachment 234418
In your case, you want to run the wire parallel to the trace. Some flux paste or liquid will clean any oxidation from the trace. You need to use a blade to scrape away the solder mask.
Will this wire suit?ezgif.com-gif-maker.jpg
 

dl324

Joined Mar 30, 2015
12,783
Will this wire suit?
Yes. It should be #30.

If this is something you're going to buy, you could take a wire from something that uses stranded wire; like an old extension or appliance cord. Current in the switch should be low, so even something as thin as #36 should work.
 

Thread Starter

zod1aq

Joined Apr 3, 2021
7
Yes. It should be #30.

If this is something you're going to buy, you could take a wire from something that uses stranded wire; like an old extension or appliance cord. Current in the switch should be low, so even something as thin as #36 should work.
Thanks, but since I dont need a whole bay of this wire can I buy just any copper wire of this thickness?
 
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