Ducky One PCB - Broke off yellow capacitor (?) block

[problemxyz]

Here is a picture of the thing that broke off.

So for the record not image of the spot where it broke off, because I still need to look for the place where that is.
So I need to know how to solder this yellow block back to the board or know for sure that the board can do without. But I have deliberately not tried hooking the board up in case this may damage other components.

Sorry if I don't seem very interested in this but Ive actually tried reading and remembering about this kind of electronics. And I kind of understand what it means but I keep forgetting everything. Except for the word capacitor itself. But not what it means haha.

[suicidal_orange]

There are two solder points, one either end.  Assuming the tabs on the capacitor are OK it depends on the traces - the one pictured would be hard to repair as one end appears to be connected to a via under the capacitor itself.  A close up pic of the hole where it should be would help.

[problemxyz]

Of course!

A close up pic of the hole where it should be would help.

Of course! Here is a picture of the actual yellow block that broke off and arrows pointing to the contacts of where it actually broke off.
EDIT: It's obvious that one one end the tab broke off. So that probably makes the job pretty much impossible unless you have some experience and skills in this realm (which I obviously don't). So then the question is if the board is unusable without this capacitor?



The previous picture was even only to show what I mean by 'yellow block' which I now realise isn't too helpful.

[suicidal_orange]

Ouch, you've ripped off most of one pad on the PCB and the other tab off the capacitor.  Is there anything sticking out of the left side of the capacitor as pictured, looks like two shiny dots in the shadow?  If not you need a new one.

From the position it looks to be to do with the RGB so the board will probably function just fine in a lit room, but your PCB is not the same as the previous pic so can't be sure.

[problemxyz]

Right.

Here is a picture of the entire PCB and a green rectangle at the location of where the capacitor broke off.
Below some more picture of the capacitor itself. On one side the tab broke off at the spot where the pins connect to the inside of the capacitor, while on the other side the tab is still attached to the capacitor and created a 'ground zero' on the PCB (most clear on my previous picture)

[Leslieann]

Show Image

I'd like to see this same shot without arrows, what's under is probably important.

I suspect it connects to the pad the bottom arrow covers (with the three diamonds) but it's hard to tell with the arrow and angle. If so you can just grind through the coating around the 3 diamonds and solder a jumper from there to the other end of the replaced capacitor. Pretty simple fix if that's the case. If you grind it just right you might even be just rotate the capacitor and do it direct without a jumper.

Also, replace the capacitor, it's cheap and while it may be salvageable it took a beating. Would you rather do this repair once or fight it then have to go back and redo it later?

[problemxyz]

I'd like to see this same shot without arrows, what's under is probably important.

I suspect it connects to the pad the bottom arrow covers (with the three diamonds) but it's hard to tell with the arrow and angle. If so you can just grind through the coating around the 3 diamonds and solder a jumper from there to the other end of the replaced capacitor. Pretty simple fix if that's the case. If you grind it just right you might even be just rotate the capacitor and do it direct without a jumper.

Also, replace the capacitor, it's cheap and while it may be salvageable it took a beating. Would you rather do this repair once or fight it then have to go back and redo it later?

No problem to purchase a new capacitor, as long as I can get my understanding far enough so the fix is something feasible.
I don't really understand what you mean grinding through the coating. So you mean desoldering the flux coating? And what would I exactly attach the jumper to?


Here is the image without the green arrows:

[PJE]

It should be fixable. It looks like the pad that broke off the PCB is connected to the region with the diamond shaped. Should be just a matter of scraping off a region of solder resist and connecting that end of the cap to it.

[Leslieann]

Pretty much what I was thinking.
Looks like you don't even need a jumper wire, scrape the diamond area and mount the cap crooked.

About as easy of a repair as you could ever hope for.

[Rico]

The diamond shape region is most probably ground, so yes scrapping the solder mask here and solder a wire from the capacitor pin to this area should do it.
Beware that those capacitors are polarized and so you must pay attention to its orientation when soldering a new one.

As for the question, should it work without this capacitor ?
I'd say maybe, but the RGB lighting will probably not work any more.
This is a high value capacitor, used to compensate for the large inrush current fo the LED driver that is next to it (the back rectangular IC next to it), I dunno what would happen without it but it is most probably mandatory.
You could still do a try, but I suspect the LED driver will make a buzzing noise (it will vibrate because of lack of smooth input DC voltage that the capacitor is supposed to ensure). Don't let the PCB plugged in for too long in this case

 

[yui]

those are filtering caps, i think, removing it should not prevent the board from working, especially if it is for the LED driver, although that one may start to behave strangely, or not, no way to know until you turn it on.
and by the way any >5V 33uF cap should work there as long as you put it the right way around (band is negative on electrolytic, i would guess the same for tantalum, but never used one so can't guaranty it, and that would put the negative on the chip side) and can scratch the solder resist to solder on the large copper zone under

[problemxyz]

As stoked as I am to try the fix as @Leslieann points out it should be really easy, I'm confused as to what the Diamond area is.
Do you mean the 3 diamond shaped pads on board, right below where the capacitator broke off? That would seem really weird, but that it's the only thing Im seeing that is diamond shaped.
Im pretty sure it's going to be embarassing when you guys are going to tell me but I guess its the only way forward 

But reassuring to know that I can test the PCB regardless, which I will try tonight.

[Leslieann]

I wouldn't hesitate to bypass it to test and if it was a junker board I'd maybe leave it but if it was a board I like I wouldn't leave it that way.

Caps are like a shock absorber for electrical bumps and dips, so long as things are smooth it's fine, but if your board spikes on power draw (like turning on or off backlighting) or your systems power fluctuates a bit it could damage something.

[Leslieann]

The 3 diamonds

[Rico]

Those are just for aestetics
Beware there is no copper below them, so if you want to ground connect a new capacitor you have to scrap the red solder mask somewere AROUND those diamonds.

[problemxyz]

So it's really those diamond looking pads. And one of the ends of a capacitor has to come into contact with one of them. Or in contact right beside them. Ok.
Still quite puzzled I must say. So you literally attach one of the tabs on that area after you scraped the coating off.? I suppose you're not just using solder for this or are you?

You guys have given me quite a bit of detail already but I have a feeling that I'm imagining this entirely wrong still.
Anyone know of any video or article that shows something similar?

Like, is Walker from Walker's Keyboard science doing something similar in this video (starting at 7:21)?

[PJE]

As Rico stated, the diamonds were actually where the ground pour was removed for aesthetics and to control the amount of heat needed to solder onto it.

I’d carefully scrape the red solder mask around the end of the capacitor when placed at a slight angle, and carefully solder to the one remaining pad, and the new ‘pad’.

Be careful not to overdo it. You can always add a jumper wire from that end to another ground point on the PCB.

I’ll see if i can sketch it out.

[PJE]

[Rico]

Yes it is very close to what Walker did in it's video. You can use normal wire to connect capacitor to ground.
PJE gives a good advice to not need the wire, it has the advantage of having the capacitor sodered on its 2 legs and it will be more robust in the end than having it soldered on the PCB with only one leg.

Either way you will have to desolder the broken pad (still attached on the PCB).

Now to find the reference of the capacitor to buy a new one...
It should be either a tantalum or polymer capacitor as it is polarized (it has an orientation).
On those led drivers having a 22uF value is quite common but it has to be confirmed.

[PJE]

The 336C capacitor is a 33uF 16V Tantalum type.

[Leslieann]

I guess I should have phrased that better bout the diamonds and mask.

[Rico]

The 336C capacitor is a 33uF 16V Tantalum type.

That's logical given the code name;)

Do you have any idea of the case size, in order to purchase a replacement ?
Maybe there is only one possible size, but I'm not sure.

[PJE]

Looking at a capacitor datasheet on Mouser.com seems to indicate that it might be a J lead 2312, but measure the one that came off to verify.

https://www.mouser.com/datasheet/2/40/J_Cap-890240.pdf

[problemxyz]

The 336C capacitor is a 33uF 16V Tantalum type.

Found a local electronics shop but not those exact values yet. Having seen the catalogue it was refreshing to see all those shapes that capacitors have.
Different in shape, but could this help me out perhaps? https://www.musikding.de/Tantalum-33uF-16V_1. Size wise it says the spacing is 2,5mm. while the yellow block off the board is 5mm x 3mm. I have a feeling this could work quite well since the legs allow for flexibility.

Looking at a capacitor datasheet on Mouser.com seems to indicate that it might be a J lead 2312, but measure the one that came off to verify.

Guess getting a new multimeter might be a better first step :-)

https://www.mouser.com/datasheet/2/40/J_Cap-890240.pdf

[Rico]

This may work and should be easier to work with.
But you have to ensure that you don't solder it in reverse otherwise it will blow up violently or even burn into flames.
Keeping the same format as the old one ensure that you will not do this mistake.
 

[yui]

The 336C capacitor is a 33uF 16V Tantalum type.

Found a local electronics shop but not those exact values yet. Having seen the catalogue it was refreshing to see all those shapes that capacitors have.
Different in shape, but could this help me out perhaps? https://www.musikding.de/Tantalum-33uF-16V_1. Size wise it says the spacing is 2,5mm. while the yellow block off the board is 5mm x 3mm. I have a feeling this could work quite well since the legs allow for flexibility.

Looking at a capacitor datasheet on Mouser.com seems to indicate that it might be a J lead 2312, but measure the one that came off to verify.

Guess getting a new multimeter might be a better first step :-)

https://www.mouser.com/datasheet/2/40/J_Cap-890240.pdf

Values are not critical, as long as they are higher, if you fin 33uF at 20V is absolutely fine, actually given that the board is 5V even going to a 10V should be fine, or going to a 50uF. as per the blowing up or going up in flames if reversed on a usb board is a bit exaggerated, it will fail but usb will not give enough power to make it violent or likely to ignite, as it will short and the usb port should shut off in that event, still better to put it the right way around. or get a ceramic so they do not have polarity but are more fragile to chocks, options are endless

[problemxyz]

Okay the input is super helpful!
Also knowing that making a mistake isnt going to set things on fire and ruin my life.

Looks like I even found the exact right one! https://www.conrad.be/p/kemet-t491d336k016zt-tantaalcondensator-smd-33-f-16-vdc-10-l-x-b-x-h-72-x-44-x-27-mm-1-stuks-501311
No?

[Rico]

Great work on finding the right capacitor reference!

Anyway as Yui said it is not critical to have the exact same value, but must be big enough (at least 20uF, and more than 5V).

Yui, I don't have personal experience with reversed polarized capacitor myself so can't confirm what would happen. Just heard bad histories so I'm extra cautious when dealing with them

Anyway, when playing with capacitors it is always safer to wear glasses (for eye protection) when you plug your board for test

[Rico]

Values are not critical, as long as they are higher, if you fin 33uF at 20V is absolutely fine, actually given that the board is 5V even going to a 10V should be fine, or going to a 50uF. as per the blowing up or going up in flames if reversed on a usb board is a bit exaggerated, it will fail but usb will not give enough power to make it violent or likely to ignite, as it will short and the usb port should shut off in that event, still better to put it the right way around. or get a ceramic so they do not have polarity but are more fragile to chocks, options are endless
[/quote]

Just found a useful video link of what could happen in case tantalum capacitor is reversed:

[yui]

i never said they can't but that they should not, they short before bursting on fire and the USB is implemented correctly should turn off the board, if you use an apple, double check, some will die when a short is on the usb

[problemxyz]

So I go the capacitor a couple of months ago and finally found the space and the courage. It worked!
I even been able to solder it straight. First there was a solderblob jammed between PCB and the new cap. So it was tilted vertically. Some heat and pressure made it eventually look quite normal.

Now im waiting on some mill max sockets for a hot swap conversion, and then the keyboard can be reassembled.

[problemxyz]

Update: installed mill max sockets, now not all keys are registering. Been looking up quite a bit and need to figure out of the whole grid thing works so that'll take me a bit

BTW

Great work on finding the right capacitor reference!

Thanks for acknowledging that. I dug hard for this and was really happy I figured this out without knowing electronics.