Cleaning old solder

[jcoffin1981]

Hey yall!  I have a bunch of switches which I have harvested from old keyboards and am cleaning, lubing, swapping a few springs, and installing on other boards.  The issue is that I did this when I had junkier equipment and, well less skill in the desoldering process.  Some of these have some solder at the base of the contact which makes it difficult to reinstall these on a new board.  I have found no easy way of cleaning it off without melting the switch housing or peeling up the contact pad.  I'm sure I'm not the first person this has happened to.  Is there an easy way to do this?  Or should I harvest new switches or buy new ones?  Thanks.

[pingmaster]

Depends on the switches. If there ultra rare, then desolder. Otherwise, junk em. Try scraping the solder with a (preferably hot) knife. Solder is a soft metal.

[tp4tissue]

NO..

just leave it..

 The more you apply heat to switches,  the more the plastic surrounding the copper contacts melt.


These are typically meant for SOLDER ONCE..  so the fact that they're desoldered already means they may be damaged, or have internal misalignment due to melted plastics.


Which is why harvesting for vintage black is kind of moot unless you have a professional solder remover gun and know how to use one.

[jcoffin1981]

Thanks TP.  I have enough extra switches (MX Brown) to get me through, although I'll have to buy more in the future.  They are cheap but I'm looking at Zealios.

Anyways, the issue I'm having now is there are a couple that I can't get to work.  I can usually fix the PCB with a fine sanded copper filament inserted to fix whatever broken trace or lifted pad that exists.  However, I cannot find any defect and this is not working.  The problem exists with the "4" key as well as the left "shift" key.  I've reinserted other switches just in case but this is not the problem. The four I can find no defect with and the shift I have not delved into yet.  I understand that these problems can be solved by connecting to adjacent switches, but I have no idea how to do this.  Is there a link you send me or very briefly explain me how to solve this?  Thanks a million.

I like the poker, but I find that it is unforgiving as far as re-soldering projects in comparison to many other boards.

[tp4tissue]

Thanks TP.  I have enough extra switches (MX Brown) to get me through, although I'll have to buy more in the future.  They are cheap but I'm looking at Zealios.

Anyways, the issue I'm having now is there are a couple that I can't get to work.  I can usually fix the PCB with a fine sanded copper filament inserted to fix whatever broken trace or lifted pad that exists.  However, I cannot find any defect and this is not working.  The problem exists with the "4" key as well as the left "shift" key.  I've reinserted other switches just in case but this is not the problem. The four I can find no defect with and the shift I have not delved into yet.  I understand that these problems can be solved by connecting to adjacent switches, but I have no idea how to do this.  Is there a link you send me or very briefly explain me how to solve this?  Thanks a million.

I like the poker, but I find that it is unforgiving as far as re-soldering projects in comparison to many other boards.

short the traces closer to the controller chip side.

If they work,  then just bridge the whole thing with thin copper wires,  it's faster than finding fault.

[merlin64]

Thanks TP.  I have enough extra switches (MX Brown) to get me through, although I'll have to buy more in the future.  They are cheap but I'm looking at Zealios.

Anyways, the issue I'm having now is there are a couple that I can't get to work.  I can usually fix the PCB with a fine sanded copper filament inserted to fix whatever broken trace or lifted pad that exists.  However, I cannot find any defect and this is not working.  The problem exists with the "4" key as well as the left "shift" key.  I've reinserted other switches just in case but this is not the problem. The four I can find no defect with and the shift I have not delved into yet.  I understand that these problems can be solved by connecting to adjacent switches, but I have no idea how to do this.  Is there a link you send me or very briefly explain me how to solve this?  Thanks a million.

I like the poker, but I find that it is unforgiving as far as re-soldering projects in comparison to many other boards.

short the traces closer to the controller chip side.

If they work,  then just bridge the whole thing with thin copper wires,  it's faster than finding fault.

Oh my gosh!! This might be the first post I've seen of yours where you're not commenting about femalezzzz lol.

[tp4tissue]

Thanks TP.  I have enough extra switches (MX Brown) to get me through, although I'll have to buy more in the future.  They are cheap but I'm looking at Zealios.

Anyways, the issue I'm having now is there are a couple that I can't get to work.  I can usually fix the PCB with a fine sanded copper filament inserted to fix whatever broken trace or lifted pad that exists.  However, I cannot find any defect and this is not working.  The problem exists with the "4" key as well as the left "shift" key.  I've reinserted other switches just in case but this is not the problem. The four I can find no defect with and the shift I have not delved into yet.  I understand that these problems can be solved by connecting to adjacent switches, but I have no idea how to do this.  Is there a link you send me or very briefly explain me how to solve this?  Thanks a million.

I like the poker, but I find that it is unforgiving as far as re-soldering projects in comparison to many other boards.

short the traces closer to the controller chip side.

If they work,  then just bridge the whole thing with thin copper wires,  it's faster than finding fault.

Oh my gosh!! This might be the first post I've seen of yours where you're not commenting about femalezzzz lol.

OH damn.. I'm messing up here..


Yes.. After you solder the keyboard,  Throw it in the garbage..

Get a hair cut and go to a -social function-  to meet females, and get their numbers..

[jcoffin1981]

Thanks TP.  I have enough extra switches (MX Brown) to get me through, although I'll have to buy more in the future.  They are cheap but I'm looking at Zealios.

Anyways, the issue I'm having now is there are a couple that I can't get to work.  I can usually fix the PCB with a fine sanded copper filament inserted to fix whatever broken trace or lifted pad that exists.  However, I cannot find any defect and this is not working.  The problem exists with the "4" key as well as the left "shift" key.  I've reinserted other switches just in case but this is not the problem. The four I can find no defect with and the shift I have not delved into yet.  I understand that these problems can be solved by connecting to adjacent switches, but I have no idea how to do this.  Is there a link you send me or very briefly explain me how to solve this?  Thanks a million.

I like the poker, but I find that it is unforgiving as far as re-soldering projects in comparison to many other boards.

short the traces closer to the controller chip side.

If they work,  then just bridge the whole thing with thin copper wires,  it's faster than finding fault.

Oh my gosh!! This might be the first post I've seen of yours where you're not commenting about femalezzzz lol.

OH damn.. I'm messing up here..


Yes.. After you solder the keyboard,  Throw it in the garbage..

Get a hair cut and go to a -social function-  to meet females, and get their numbers..

This is the funniest thing I've heard/read all week.  Yes this sounds a lot easier because I can't find the defect in the connect on the pcb.  I assume there is no disadvantage or performance issue with this rather than doing the harder troubleshooting route?

[jcoffin1981]

What is very strange is that the caps lock key works and it functions as Fn.  All of the function layers work and the "3" key works, but "F3" does not.  I can't wrap my head around this.  The other F1 through F12 keys work however.  I don't know how often I really need F3, but when I do I will be at a disadvantage.

I'm sure somebody with more knowledge can explain this.  (Maybe I should have started a new thread, but I'm still on the same project).

[tp4tissue]

What is very strange is that the caps lock key works and it functions as Fn.  All of the function layers work and the "3" key works, but "F3" does not.  I can't wrap my head around this.  The other F1 through F12 keys work however.  I don't know how often I really need F3, but when I do I will be at a disadvantage.

I'm sure somebody with more knowledge can explain this.  (Maybe I should have started a new thread, but I'm still on the same project).

look at the section of the trace unique to f3  follow it up and down..   multimeter those sections.

If it's a _colored_ pcb (not translucent,  then visually spotting cracks might be impossible..) so you have to multimeter

[jcoffin1981]

What is very strange is that the caps lock key works and it functions as Fn.  All of the function layers work and the "3" key works, but "F3" does not.  I can't wrap my head around this.  The other F1 through F12 keys work however.  I don't know how often I really need F3, but when I do I will be at a disadvantage.

I'm sure somebody with more knowledge can explain this.  (Maybe I should have started a new thread, but I'm still on the same project).

look at the section of the trace unique to f3  follow it up and down..   multimeter those sections.

If it's a _colored_ pcb (not translucent,  then visually spotting cracks might be impossible..) so you have to multimeter

 

This is helpful, but I'm not able to get readings on the traces, only at the contact points or the diodes.  They seem to be covered in some kind of protective laquer or finish,  but I also can't determine what traces are unique to F3 vs 3.   I'm not a noob, but not an electronics engineer.  I get about 0.7V at the contacts, but obviously the defect is somewhere before the contacts.

[tp4tissue]

This is helpful, but I'm not able to get readings on the traces, only at the contact points or the diodes.  They seem to be covered in some kind of protective laquer or finish,  but I also can't determine what traces are unique to F3 vs 3.   I'm not a noob, but not an electronics engineer.  I get about 0.7V at the contacts, but obviously the defect is somewhere before the contacts.

Test for resistance,  connect vs disconnect,   you don't need a voltage reading.

or use the diode beep setting if your meter has that.


the board should be OFF when you test..

Unless you 've fried it already putting voltage every where willy nilly, hahahahaha

[jcoffin1981]

Okay, forgive my ignorance.  Okay, it's disconnected, duh, if you are testing for resistance.  Yes I have an audible alert for an open circuit and I assume that's what you are referring to.  It's not a Fluke but has most needed functions.  I can also test for resistance.  The problem is I cannot test the traces anywhere as they seem to be coated by a protective film, so the only place I can get a reading for anything is the switch contacts or diodes.  Anyplace in between on the pcb traces I can't measure anything.  This is a Poker 3, but I assume that this is no different than any other board.  This is baffling to me but you seem to know the problem I need to investigate Tp.  By the way, If I find a break in the trace can I fix it with some fine motor skills and fine solder?

[tp4tissue]

Okay, forgive my ignorance.  Okay, it's disconnected, duh, if you are testing for resistance.  Yes I have an audible alert for an open circuit and I assume that's what you are referring to.  It's not a Fluke but has most needed functions.  I can also test for resistance.  The problem is I cannot test the traces anywhere as they seem to be coated by a protective film, so the only place I can get a reading for anything is the switch contacts or diodes.  Anyplace in between on the pcb traces I can't measure anything.  This is a Poker 3, but I assume that this is no different than any other board.  This is baffling to me but you seem to know the problem I need to investigate Tp.  By the way, If I find a break in the trace can I fix it with some fine motor skills and fine solder?

u can usually fix the trace, by sanding the top lacquer off where the break is, and bridging with solder, but this joint is susceptible to cracking. It's easier to just take a thin copper wire and go where you need to go.


take a picture of the pcb, where the traces show up well,   

[ander]

Old solders never die—they just fade away.

[jcoffin1981]

Sorry, I haven't been on for a few days.  Thanks TP.  One switch I was able to fix, actually by temporarily wiring to adjecent switches and seeing which of the contacts was intact with the PCB and fixing the other contact.  The other one has what appears to be a damaged diode, which is easy enough to swap out from a donor board as I have a few.  Problem is my Weller station has a chisel tip which I HATE and is difficult to use expecially for small surface mounts.  I prefer conical contrary to most other's opinions.  I have 20 Hakko tips and they don't fit.

With the Fn problem I cannot find any physical defect or even know where to photograph.  I use the key so little that I may just forgo any attempt to fix it.  This board I rarely use.  Thanks for all the comments and help and if there is anything to add please let me know.