switch replacement in qfr

[adventurepoop]

I'm getting a qfr in a few days, with black switches. If I don't like the blacks would it be a good idea to replace them with blues or something? Is there any risk of destroying anything this way?

[fohat.digs]

That is a lot of work and the QFR is pretty inexpensive anyway. By the time you buy the switches and spend a couple of hours doing it, you might as well have sold the original for 80% of what you paid and bought a new one.

[Melvang]

I would swap the switches out just for the experience of doing it.

[geniekid]

I'm getting a qfr in a few days, with black switches. If I don't like the blacks would it be a good idea to replace them with blues or something? Is there any risk of destroying anything this way?

You'll need to desolder any switch you want to replace and solder in a new one.  There's always an inherent risk while soldering/desoldering that you'll damage the PCB.  That said, if you're comfortable soldering/desoldering it's very low risk - lots of people have done it without problems.

And, like Melvang said, it's a good learning experience.  I did it on my QFR a couple of months ago and it was my second time desoldering.

[Melvang]

Plus iirc the QFR is a single sided PCB which makes the desoldering easier to do but at the same time the pads are slightly more susceptible to lifting.  Though fixing that is easy with some hookup wire.

[swill]

Just a word of warning. The QFR has a very cheap PCB and the pads lift very easily. You will not be able to desolder and resolder very many times before you will require hookup wires.

I was amazed be the poor quality when I started desoldering mine.

[adventurepoop]

Okay thanks for the input everyone! Basically someone is selling me a qfr w/ blacks, and 80 some blue switches for 65$ shipped, and I'm trying to decide if I should do it or not.

[Grendel]

I have done it to multiple QFR/S and a RK-9000. Using the right equipment it's very easy w/ minimal risk if you don't heat a pad longer than 5s at a time. However, I would suggest to pass on that offer -- you can get a new QFR w/ brown switches for $72 right now.

[adventurepoop]

But this way I also get a bunch of switches to do project stuffs with

[domoaligato]

adventurepoop,

Do you plan to do a quite a bit of soldering/desoldering with through hole soldered pcb's?

Do not use a cheap radioshack desoldering pump.
They are a waste of money.

In fact do not buy anything from radioshack.

Either buy quality desoldering braid and resin or a hakko 808
I bought a hakko 808 desoldering gun because I was desoldering/resoldering quite a bit and it saved me from insanity.

To do this stuff right requires a little bit of an investment but after the initial cost and learning curve you will enjoy the hardware you buy for many many years to come.

Also this thread is where we discuss all soldering related stuff.
please check it out as it basically showed me the light
http://geekhack.org/index.php?topic=42824.0


edit: forgot about solderpults... anyways that info is all in that thread I linked.

[dorkvader]

Just a word of warning. The QFR has a very cheap PCB and the pads lift very easily. You will not be able to desolder and resolder very many times before you will require hookup wires.

I was amazed be the poor quality when I started desoldering mine.

i want to echo this: be careful to not lift pads.

That said the PCB isn't that bad for a keyboard. Cherry is worse quality wise, and this stupid filco is one of the worst keyboards I've ever desoldered.

In fact do not buy anything from radioshack.

This guy knows what's up.

I have a hakko 808 which keeps breaking, so the soldapullt may be the best option anyway.

[PointyFox]

Just a word of warning. The QFR has a very cheap PCB and the pads lift very easily. You will not be able to desolder and resolder very many times before you will require hookup wires.

I was amazed be the poor quality when I started desoldering mine.

i want to echo this: be careful to not lift pads.

That said the PCB isn't that bad for a keyboard. Cherry is worse quality wise, and this stupid filco is one of the worst keyboards I've ever desoldered.

In fact do not buy anything from radioshack.

This guy knows what's up.

I have a hakko 808 which keeps breaking, so the soldapullt may be the best option anyway.

My Hakko 808 is fine :X
I bought it because I was failing to desolder stuff from my Poker II with its double layer PCB.  Returned several things to Radioshack before giving up and getting the Hakko

[whiskytango]

Yeah, for dual layer PCB having a 808 makes life much easier. However, I desoldered a bunch of boards with a RS bulb iron without much difficulty. Just be aware the RS tips wear out very quickly.

[dorkvader]

on mine, the tube that goes between the tip and the chamber gets clogged. I hope to solve this with a dedicated cleaner that I can use every joint or two.

I can second the terrible RS tips. I think I threw mine away. My OKI (now metcal) makes desoldering a lot easier. It gets value for it's help in desoldering alone. The fact that it's an awesome soldering station makes it epic. I've done like 5-10 boards with it and no tip wear.

[whiskytango]

on mine, the tube that goes between the tip and the chamber gets clogged. I hope to solve this with a dedicated cleaner that I can use every joint or two.

I can second the terrible RS tips. I think I threw mine away. My OKI (now metcal) makes desoldering a lot easier. It gets value for it's help in desoldering alone. The fact that it's an awesome soldering station makes it epic. I've done like 5-10 boards with it and no tip wear.

Yeah, that's not normal at all for an 808. I barely ever have to clean out that tube. Maybe once every couple of boards' worth of desoldering. It is a pain to have to remove the tip while the iron is hot so that you can use the cleaning tool that comes with the unit.

Are you saying that you are looking for a tool that will clean out the tube without removing the tip? That would be handy. Maybe some music wire of the proper diameter would work to fashion such a tool since it would need to be longer than the stock tip cleaning tool. However, it sounds to me like your unit might be defective somehow.

[domoaligato]

I had the same issue dorkvader, the kit comes with a rod to jam through it, about every 5-10 joints push the rod through the tip and tube into the chamber. This cleaning has helped a lot.

[PointyFox]

Yeah, it comes with two rods for keeping that clear.

[legodt]

What are pads?

[whiskytango]

What are pads?

Solder pads. The little rings of copper around the holes in the PCB that the solder sticks to. On a single sided board like the QFR has, the pads are only on one side, they are very thin, and they are susceptible to being "lifted" off the board meaning the little copper rings can become detached from the PCB if you are not careful when soldering or desoldering. If you apply too much heat for too long, this can happen.

[legodt]

that is goddamn horrifying, thank you for informing me.

[HotKillerZzz]

But if they come out, don't panic.
First time I soldered I was soldering a qfr. The solder pad came out and I didn't even know.
If It comes out just take any spare wire from your home to fix it. It's a great experience too. GLHF!!

[berserkfan]

Just a word of warning. The QFR has a very cheap PCB and the pads lift very easily. You will not be able to desolder and resolder very many times before you will require hookup wires.

I was amazed be the poor quality when I started desoldering mine.

Surprisingly after several low end keyboards, I have never lifted a pad before, despite being clumsy, not electronics-educated, having zero prior experience, cheap equipment, etc.

I think one problem that the skilled and experienced pros have, and which I don't have, is that their equipment is too good. AKA soldering station is too hot and solder sucker is too powerful. This is good for desoldering top end stuff quickly and efficiently.

Am venturing a guess that when you are desoldering cheapo PCBs, you should use cheapo equipment and budget more time.

[Melvang]

Just a word of warning. The QFR has a very cheap PCB and the pads lift very easily. You will not be able to desolder and resolder very many times before you will require hookup wires.

I was amazed be the poor quality when I started desoldering mine.

Surprisingly after several low end keyboards, I have never lifted a pad before, despite being clumsy, not electronics-educated, having zero prior experience, cheap equipment, etc.

I think one problem that the skilled and experienced pros have, and which I don't have, is that their equipment is too good. AKA soldering station is too hot and solder sucker is too powerful. This is good for desoldering top end stuff quickly and efficiently.

Am venturing a guess that when you are desoldering cheapo PCBs, you should use cheapo equipment and budget more time.

The number one cause for lifted pads is to much heat and heat for to long.

[swill]

Just a word of warning. The QFR has a very cheap PCB and the pads lift very easily. You will not be able to desolder and resolder very many times before you will require hookup wires.

I was amazed be the poor quality when I started desoldering mine.

Surprisingly after several low end keyboards, I have never lifted a pad before, despite being clumsy, not electronics-educated, having zero prior experience, cheap equipment, etc.

I think one problem that the skilled and experienced pros have, and which I don't have, is that their equipment is too good. AKA soldering station is too hot and solder sucker is too powerful. This is good for desoldering top end stuff quickly and efficiently.

Am venturing a guess that when you are desoldering cheapo PCBs, you should use cheapo equipment and budget more time.

The number one cause for lifted pads is to much heat and heat for to long.

Ya. I should desolder it completely now that I have my new soldering station dialed in. I am going to be using it only for parts at this point anyway. I would resolder the whole board to fix it if I didn't have better boards at this point. I should really just give it away.

[berserkfan]

Guys, do you even touch the solder tip to the solder droplet, rather than to the PCB? Maybe it is my lousy equipment, but it always takes a while for the solder droplet to melt/ soften if it is lead free solder. So I never have to worry about heating something too long. At the miserable rate of heat transmission that I'm getting, it'll probably take a minute or two before the pad can be lifted.

[Melvang]

Remember that lead free solder is much more difficult to remove without lifting pads due to the higher melting temp.  Before I desolder anything that is lead free, I add leaded solder to the pad first.  Chances are you will not get to the 63/27 magic number but you will get close enough to reduce the melting temp by a significant amount.

[berserkfan]

Remember that lead free solder is much more difficult to remove without lifting pads due to the higher melting temp.  Before I desolder anything that is lead free, I add leaded solder to the pad first.  Chances are you will not get to the 63/27 magic number but you will get close enough to reduce the melting temp by a significant amount.

Do you have any advice about avoiding lifting pads, apart from 'not heating too long'? For instance, how are the pads mechanically fixed onto the PCB? What materials are they made of? Is it possible to use super glue or fohat's favorite JBweld and just stick back the pads? Can I substitute small copper or steel rings and stick them onto a lifted pad? Anything that improves our understanding!

[Melvang]

I have only lifted a couple and the few trace repairs I have done were from intentional breaks.  I do know that (at least on single sided PCBs) that the pads are glued down though I am not sure what type of glue is used.  The biggest piece of advice that I can give and I have seen mkawa along with others use for not lifting pads is "Get in, Get out".  Just keep you iron set right, 350°C for 63/27 not sure on lead free, get it melted, do what you need to do and get out quick.  That being said, if desoldering and re soldering a single sided board multiple times you are probably bound to lift a pad from time to time regardless of how careful you are.

That being said I have two suggestions for trace repair.  I will list them in order of ease of being able to do the work, with the easiest being first.

1.  Follow the trace from where the broken pad is to the next solder pad and simply connect the pin at the lifted pad to the next one down (or up) the line, it shouldn't matter which direction you go so long as you are on the same trace.  This is what I did when I modified my Das for the HDD activity LED mounted above the switch instead of the stock below the switch orientation.  For this I had to add the LED and rotate the switch from stock placement.  This meant drilling holes through the PCB and breaking traces.  Wasn't to bad really.

2.  Scrape the solder mask from the top of the trace next to the location of the lifted pad.  Then take a piece of a clipped lead from a diode or an LED and simple connect the trace to the pin of what ever you are trying to solder.  This will be more difficult to actually accomplish as you are essentially doing SMD style soldering but has a much cleaner and professional look to the finished job.

As far as gluing the pad back down using super glue or jbweld, I can't speak for that.  Though I would say that if the pad is still attached to the trace than you would have a much better chance of it working.  If the pad completely separates from the trace, you will still have to connect the pad to the trace electrically.

[berserkfan]

Melvang,

Isn’t ‘connecting electrically’ all about physical contact? If the pad is physically lying on or against the trace, it should be connected, right?

I’m just trying to understand, sorry if I sound like a 3 year old. As for your first suggestion, you are talking about connecting the pin using a wire, right?

[Smasher816]

Isn’t ‘connecting electrically’ all about physical contact? If the pad is physically lying on or against the trace, it should be connected, right?

Sounds correct. But I could easily see the glue getting between the trace and pad electrically isolating the two.

[berserkfan]

Sounds correct. But I could easily see the glue getting between the trace and pad electrically isolating the two.

What glue is it anyway? I figure that if we can use glue, woudn't that be less awkward than using wires?