Need help with lifted pads on poker 2

[kohi]

So basically, my left control and spacebar keys don't work because I accidentally lifted the pads off them. Usually it isn't much of a problem since the pcb itself is double-sided - but I can't get the keys to work this time around. I'm not too familiar with repairing traces/finding where to bridge connections etc, so any help would be nice. thanks!

[suicidal_orange]

Basically one leg of each switch will connect directly to (probably the same up/down) leg on a nearby switch, the other leg connects to a diode.  If you lifted the directly connected pad you might have to connect it to two switches so the keys after it work - not sure if these two are supposed to be connected but I would guess not.

If you need more help we'll need a picture showing the traces.  It's double sided so no promises, but a little guesswork should get it done

[kohi]

Basically one leg of each switch will connect directly to (probably the same up/down) leg on a nearby switch, the other leg connects to a diode.  If you lifted the directly connected pad you might have to connect it to two switches so the keys after it work - not sure if these two are supposed to be connected but I would guess not.

If you need more help we'll need a picture showing the traces.  It's double sided so no promises, but a little guesswork should get it done

ah ok, so does it matter which legs are being bridged together? or would any other switch leg do..
here are some pics (sorry for bad quality)

[suicidal_orange]

It's important to find a right place to solder to, otherwise the switch will register as another key

This is a great example of a double sided PCB, invisible traces and they don't even put the diode on the same switch leg - very hard to see anything!

From what I can make out the pad you haven't lifted on both switches is attached to the diode (yellow lines) and there's a trace off one dead pin (green line) which may well join up with the pad at the other end of the line - hopefully you can make it out easier in person.  If that is the case you can solder a wire between those two and that switch will work again.



The other one could be really bad as the trace heads off towards the controller (orange line)  You can try touching a wire from the non-lifted pad to whichever pin on the switch next to it isn't attached to a diode, if that works solder from that pin to the lifted pad - if in doubt please post a bigger pic of that area and I'll try and be less vague, but they've not been helpful )

Trying not to make you scrape the blackness off, but if all else fails you can reveal the trace under the orange line and solder to that...

[kohi]

It's important to find a right place to solder to, otherwise the switch will register as another key

This is a great example of a double sided PCB, invisible traces and they don't even put the diode on the same switch leg - very hard to see anything!

From what I can make out the pad you haven't lifted on both switches is attached to the diode (yellow lines) and there's a trace off one dead pin (green line) which may well join up with the pad at the other end of the line - hopefully you can make it out easier in person.  If that is the case you can solder a wire between those two and that switch will work again.

Show Image

The other one could be really bad as the trace heads off towards the controller (orange line)  You can try touching a wire from the non-lifted pad to whichever pin on the switch next to it isn't attached to a diode, if that works solder from that pin to the lifted pad - if in doubt please post a bigger pic of that area and I'll try and be less vague, but they've not been helpful :))

Trying not to make you scrape the blackness off, but if all else fails you can reveal the trace under the orange line and solder to that...

Show Image

thanks! I'll give the first one a try and see how it goes. so basically just bridge the two switch legs using a wire as indicated (green line) right?
as for the second one (spacebar), are you suggesting I try something like this (see attached pic)? sorry wasn't clear..

[suicidal_orange]

thanks! I'll give the first one a try and see how it goes. so basically just bridge the two switch legs using a wire as indicated (green line) right?

You see how the top right of your pic is shiny and has clear lines? Those are what I'm trying to see in the dark bit, so you need to check that the trace I've highlighted green actually connects to the left pad before soldering - it might skip that one and connect to the next switch instead.  Or the next switch...

as for the second one (spacebar), are you suggesting I try something like this (see attached pic)? sorry wasn't clear..

I think the second one only goes up to a small hole which takes the trace onto the other side which is where the orange line stopped.  Again - you can see better as you have the board in front of you and can twist it in the light so feel free to tell me I'm wrong.

I'm not saying it doesn't connect to the next switch up, but if it's consistent (it isn't in other ways so no reason it should be) and the first fix is correct then the non-diode connections are horizontal and the diode ones vertical.   Or they could be grouped into 8s of two switches in each row.  Or they may be completely random!

[kohi]

[quote author=suicidal_orange link=topic=77196.msg1941718#msg1941718
I think the second one only goes up to a small hole which takes the trace onto the other side which is where the orange line stopped.  Again - you can see better as you have the board in front of you and can twist it in the light so feel free to tell me I'm wrong.

I'm not saying it doesn't connect to the next switch up, but if it's consistent (it isn't in other ways so no reason it should be) and the first fix is correct then the non-diode connections are horizontal and the diode ones vertical.   Or they could be grouped into 8s of two switches in each row.  Or they may be completely random!
[/quote]

I'll check the trace for the first one again later to see if it actually connects to the pad on the left of it and let you know.
for the second one, it does end at the small hole you see in the picture. Would I need to see where the trace goes on the front side of the PCB then?

[suicidal_orange]

I'll check the trace for the first one again later to see if it actually connects to the pad on the left of it and let you know.
for the second one, it does end at the small hole you see in the picture. Would I need to see where the trace goes on the front side of the PCB then?

That would be the easiest way to see but if that means more desoldering I don't suggest it - the PCB has let you know it's had enough already )

The other way to work it out is to touch the pin that's not connected to the diode of another switch (the one at the top of your green line is an option) to the good pin on the space bar switch - if that detects as a space you can solder it to the lifted pad's leg, but it may well detect as the key above or nothing at all.

You can't do any damage by connecting switch pins at random so if you're bored that's an option.

[kohi]

That would be the easiest way to see but if that means more desoldering I don't suggest it - the PCB has let you know it's had enough already )

The other way to work it out is to touch the pin that's not connected to the diode of another switch (the one at the top of your green line is an option) to the good pin on the space bar switch - if that detects as a space you can solder it to the lifted pad's leg, but it may well detect as the key above or nothing at all.

You can't do any damage by connecting switch pins at random so if you're bored that's an option.

haha yeah, it's been desoldered/soldered several times and the glue holding down the pad finally gave up
the board is currently desoldered, so I do have access to the front of the board. I will see what I can do. in order to test the keys by "touching" the pins using a wire, don't the switches need to be soldered in already? and are you suggesting that I do something like this? to test it?

[suicidal_orange]

That is how to test but as it's unsoldered already a pic of the other side should be much easier.  Try and get the shiny bit around the holes for that switch

[kohi]

That is how to test but as it's unsoldered already a pic of the other side should be much easier.  Try and get the shiny bit around the holes for that switch

haha alright, I'll try to get a better pic of the traces later when I get home
I'll try to get a pic of the front side of the pcb near the spacebar as well, but it might be hard because the plate is soldered onto to pcb, so I have to remove that first

[filphil]

That would be the easiest way to see but if that means more desoldering I don't suggest it - the PCB has let you know it's had enough already )

The other way to work it out is to touch the pin that's not connected to the diode of another switch (the one at the top of your green line is an option) to the good pin on the space bar switch - if that detects as a space you can solder it to the lifted pad's leg, but it may well detect as the key above or nothing at all.

You can't do any damage by connecting switch pins at random so if you're bored that's an option.

haha yeah, it's been desoldered/soldered several times and the glue holding down the pad finally gave up
the board is currently desoldered, so I do have access to the front of the board. I will see what I can do. in order to test the keys by "touching" the pins using a wire, don't the switches need to be soldered in already? and are you suggesting that I do something like this? to test it?

In that picture you can jump a wire from the left pin to the diode immediately to the left. 

I'm not sure about the right pin but since it's desoldered you can follow the trace to the next pin in line and jump to that. 

[kohi]

In that picture you can jump a wire from the left pin to the diode immediately to the left. 

I'm not sure about the right pin but since it's desoldered you can follow the trace to the next pin in line and jump to that.

I'm not too worried about the left pin since a portion of the pad is still attached to the joint so it should work.

For the right pin, I need to look at the other side of the pcb to see where the trace connects.. hopefully it isnt too hard to see;

[kohi]

so I tried touching the pins with wire to see if it would work, and nothing happened for both the spacebar and the control. I tested it out on other keys, and it worked for them (ex. I bridged the 'm' key with the switch on top of it, and the "m" key registered). I guess I'm out of luck?

[suicidal_orange]

There is almost certainly somewhere that will work, you just haven't found it yet - try and get a shiny pic of the back if you can't get the plate off.

[kohi]

There is almost certainly somewhere that will work, you just haven't found it yet - try and get a shiny pic of the back if you can't get the plate off.

I guess I found a potential solution. I actually found where the pad broke off and a little bit of the trace was exposed, so I just added a lot of solder to connect the switch pin to the small exposed area and the spacebar works! If this fix stops working, I guess I'll try to find where the trace connects to, but for now, it works so... hopefully it lasts. have to try for control key now...

[kohi]

alright, it worked for the control key as well. whew, now everything is good to go!