Need help with severely damaged PCB

[Jonwong966]

I have a client that tried to solder his own keyboard but didn't have the right tools. He contacted me and asked me if I can fix it. The first time I examined the PCB, I honestly didn't think I can salvage a PCB in its condition. So just to be safe, I told my client to order another PCB while I desolder all his mistakes. I finished his keeb and it is completely functional after some software flashing and googling. I now have his old PCB and I was wondering if I can salvage it at all. Doing some further inspection, I was able to spot that somehow he completely removed a diode (D64) and burnt a capacitor (C8). (I actually can't confirm if those are the correct names for those parts but I am assuming from the "R" "C" & "D" it means resistor, capacitor, diode respectively) I don't know what the name of the PCB is so I can't find any circuit diagram that is similar to it. I believe it is a DZ60 clone but I'm not 100% sure. I tested the keyboard in switch hitter and it seems that most of the keyboard works. The only exception is ESC, Tab, Caps, Left Shift, Left Ctrl, Z, ?, Right Shift, FN, and Right Winkey. Is it even worth trying to fix this PCB or should I just use it as a teaching PCB for friends?

[Sup]

Bro that is a DZ60. to fix it you will have to use a jumper if the pads are burnt but i have no experience with that though.

[Leslieann]

Not to beat up on the guy, everyone has to learn to somewhere, but what the heck.
This just looks like carelessness, so many things damaged that had no reason to be hear a hot iron.

I suspect it can be fixed as it sounds like the left column and right column leads have been damaged.

Just a guess since I can't see well enough from the pics...
Check the diode next to ESC, I'm betting it's dead or not connected, this is taking out the whole left column.
Same for the right, check the diode next to the shift.

My guess is they ran the columns down then across for the mods rather than just straight down into the mods. The diodes are the easiest thing to test and deal with. You can check them with a volt meter or even just jump over them and see if you get a signal it will not damage anything except NKRO. This may not solve it, but at least maybe point you in the right direction.

[nmur]

Yeah this is why it's wise to learn how to solder with a pcb that you don't care too much about, or a kid's learning kit or something

It honestly looks like this guy was soldering with a butane torch

[Leslieann]

Soldering switches are one of the easiest things you can solder, there's nothing close and the pins are large and pre-cut.

They seemed to have managed that so they got the basics, I just don't understand the iron bumping so many other things that aren't near the switch pins.

[Jonwong966]

Not to beat up on the guy, everyone has to learn to somewhere, but what the heck.
This just looks like carelessness, so many things damaged that had no reason to be hear a hot iron.

I suspect it can be fixed as it sounds like the left column and right column leads have been damaged.

Just a guess since I can't see well enough from the pics...
Check the diode next to ESC, I'm betting it's dead or not connected, this is taking out the whole left column.
Same for the right, check the diode next to the shift.

My guess is they ran the columns down then across for the mods rather than just straight down into the mods. The diodes are the easiest thing to test and deal with. You can check them with a volt meter or even just jump over them and see if you get a signal it will not damage anything except NKRO. This may not solve it, but at least maybe point you in the right direction.

In photo 4, u should be able to see diodes d17 and d33. I don't see anything obvious about them but I'll take a voltmeter to it. The capacitor at C8 looks significantly damaged so I will probably look for a replacement for that. When I plug in the PCB now, it holds the whole right collum down and I don't know how something is bridging a connection between any of the pins. I'll further look into this. But I do have another question. are the "for spares" Diodes and resistors free to take off and use? I need to make sure before I remove it.  And sorry for the blurry photos, I don't have a microscope cam so I'm propping my phone on a cup and zooming.

[Jonwong966]

Yeah this is why it's wise to learn how to solder with a pcb that you don't care too much about, or a kid's learning kit or something

It honestly looks like this guy was soldering with a butane torch

My dude mauled a bunch of switches too! I genuinely have no idea how he did it. I was considering using this PCB as a teaching board for clients or friends if they were ever interested in the hobby.

[BrickParade]

But I do have another question. are the "for spares" Diodes and resistors free to take off and use? I need to make sure before I remove it.  And sorry for the blurry photos, I don't have a microscope cam so I'm propping my phone on a cup and zooming.

i had to swap a diode on my DZ60 a few weeks ago and I can confirm that the "for spare" diodes and resistors are indeed just spare parts in case you need to make repairs. the diodes don't necessarily have to look bad to be bad so checking them with a meter is definitely a good idea

[suicidal_orange]

Is it just the picture or is R5 bypassed by solder too?

Looking at the not great schematic someone posted (see below) it seems C8 connects the RGB LEDs to the USB port so I guess that's where they're powered from.  The diodes for the left column actually link back through a via above D62 (left shift) so if there is a single point of failure it could be there.  That trace goes to the highest of the three vias between C6 and C5 near the controller so you could try shorting then jumping to there.



As long as the controller isn't damaged it's fixable but if you want to use it to show friends how not to do it you'll never find a better example

[Jonwong966]

Is it just the picture or is R5 bypassed by solder too?

From what I see from visual inspection, he either reflowed the solder there and it is not even or it was melted so that could be another point of failure. Need to grab batteries for the voltmeter so I won't be able to confirm if is bypasssed.

[tp4tissue]

Yoos guyz r 2 harsh,  the dude could have tourette's. 

[Leslieann]

In photo 4, u should be able to see diodes d17 and d33. I don't see anything obvious about them but I'll take a voltmeter to it. The capacitor at C8 looks significantly damaged so I will probably look for a replacement for that. When I plug in the PCB now, it holds the whole right collum down and I don't know how something is bridging a connection between any of the pins. I'll further look into this. But I do have another question. are the "for spares" Diodes and resistors free to take off and use? I need to make sure before I remove it.  And sorry for the blurry photos, I don't have a microscope cam so I'm propping my phone on a cup and zooming.

Diodes rarely show damage, but they are simply one way gates.
If you jumper it, NKRO will no longer work but the switch will, but you have to pass a signal through one way or another. A missing diode is definitely part of the problem.

It wasn't the pictures, I was just unable to zoom in on them more than the browser already was.

The cap is part of the power system, if the keyboard and RGB work, it's probably okay.
I'd still consider changing it, but if it's bad a whole sub system will be out, not just one collum.