So my bro recently gave me a broken MIDI keyboard. He said the only problem with it is that the USB connector (I think mini usb?) broke off of the circuit board. He tried to solder it back on, and it looks like he may have fucked it up beyond repair. Its pretty burnt, the green part of the board is coming up a little, and the actual component has solder all over it. My question: how do I check if it still works? I definitely need to buy a new mini usb because their is solder all over the four little prongs on the back. But I want to check if it would even work before I waste my time. Ill attach a picture of the spot where he tried to solder.
It looks like all the electrical contacts are still fine. Those four large pads are just to hold the socket on the board. Cut a USB extension cord in half and solder each of the wires individually. You should be able to figure out which wire goes where with a continuity tester or by looking at the old socket. Then you'll have to find some way to securely hold the cord, because any tension will just break all those solder joints.
>>948252
you dont have to trace shit
its already done
>>948265
easiest way to do it would to coat the wire in solder, not a huge glob just enough to coat it, then touch the wire to the pad and heat it up. should stick right to it with no mess.
>>948269
Ahh yes, that makes infinite amounts of sense. Thanks a lot bro, you're super helpful!. Any suggestions about how to secure the wire after I solder?
>>948279
you could tie a loose knot in it and feed it out the old usb hole.
>>948282
For sure for sure, that sounds like a great idea! or at least attach something larger than the hole to the inside and outside so I cant push it inwards or outwards. Good call, Thanks so much!
>>948246
akai mpk mini?
>>948293
Yep! I've been reading and apparently this is a really common problem with the mpk mini. You have the same issue?
>>948265
>Is it a problem if solder holding one wire in place is touching the solder from another?
Yes, this is called a bridged solder joint, because molten solder has flowed between two pads and formed an electrical "bridge". This is to be avoided at all costs. A check with a multimeter will always reveal them though.
>>948288
Sounds like a good idea but ensure you glue or otherwise bond a good half inch of the cord to the PCB and loop it back out. This will prevent the constant movement from braking the wires away from the pads due to metal fatigue. I would be inclined to bond it to the bottom shell of the device rather than the PCB, but that just depends on where you have space I guess.
>>948305
>braking
*breaking
>>948246
>my bro
wew you fucked that repair up pretty badly, just buy a new keyboard.
>>948308
Here's your reply.
>>948305
Actually, screw this noise, go get a pic related instead. Shit should last the life of the keys.
>>948321
Expensive, but yes, those are nice.
>>948305
>948305
Okay ya, I thought that sounded like a bad idea haha. But I wasn't 100% as to whether solder was conductive. And thanks for the graphic bruv. What would the best "bond" be? is some electrical tape solid? or do I need to use some sort of adhesive or something else?
>>948308
Lel, thats why I don't wanna take it to a repair shop instead. Cause as soon as I say "my friend," I know they'll be like "your friend huh?? hahahahahahaha!" and I'll be like "no really" and they'll be like "hahahahahahahahaha ya, im sure."
>>948321
For sure, I would, but I'm looking to spend $0. I already have a MIDI keyboard and I'll prolly wind up giving this one away. I just thought it sounded like a good learning experience. But thank you, cause now I'm aware that those exist
>>948377
I would be using a two part epoxy, ensuring the cable is completely surrounded. If budget is biting you and you have some spare hardware floating around, you can ghetto up a cable relief like pic related using some thin HDPE or PET plastic (think drink bottles) as a loop to restrain the cable. Cut a strip, wrap it around the wire, punch a hole through both ends close to the wire, then bolt the whole thing down to the base plate, leaving enough cable internally to manouver and reassemble the unit. Either method should outlive the keyboard.
