That soldering indeed looks .. not great. Use flux to fix it, its possible you have more things connected than needed 😀

rasz_pl wrote on 2023-12-28, 23:50:

That soldering indeed looks .. not great. Use flux to fix it, its possible you have more things connected than needed 😀

Yes, I know, it is far from great, but some of the points needed to be long as I torn some traces. Will fix those.
Still, I have checked each point several times, nothing is shorted or connected where it should not be.

It is strange that keyboard works but it reports problem. This is what I don't understand. Maybe voltage problem? In case I burned some components on the other side.

EDIT1:

Usually keyboard can report a problem yet still works when the computer is turned with a key held down during boot.
I'm guessing you shorted something that shouldn't. Double check if there is any continuity between your solder points first, then between the solder points and a ground point, making sure only ground pins do make a beep and nothing else.

And yes, please use flux.

wbahnassi wrote on 2023-12-29, 13:59:

Usually keyboard can report a problem yet still works when the computer is turned with a key held down during boot.
I'm guessing you shorted something that shouldn't. Double check if there is any continuity between your solder points first, then between the solder points and a ground point, making sure only ground pins do make a beep and nothing else.

And yes, please use flux.

Yes, I checked everything like 10 times. I put one probe to the connector hole, and the other probe to the solder point and to the wire trace where it was possible. Everything is fine.
Also nothing is connected to the ground what should not be. There is one pin tough, which should be grounded (based to the scheme) but it doesn't beep on ground point. I tried to short it with the ground but the result was the same.
I am only thinking that I damaged something on the other side, but I am not that smart to figure out what.
I use flux, I only don't know how good it is as it was a cheep one.

have you checked if there are traces on the top of the pcb?
they can rip off very easy when desoldering because you pull them of the board together with the connector if the solder is not fully molten...

DerBaum wrote on 2023-12-29, 16:29:

have you checked if there are traces on the top of the pcb?
they can rip off very easy when desoldering because you pull them of the board together with the connector if the solder is not fully molten...

Didn't see any traces on the other side. What I discovered just now is that I have too low voltage on the keyboard, 2.5V when it should be 5V 🙁

boby wrote on 2023-12-29, 17:12:

What I discovered just now is that I have too low voltage on the keyboard, 2.5V when it should be 5V 🙁

A short somewhere 😬

wbahnassi wrote on 2023-12-29, 17:17:

boby wrote on 2023-12-29, 17:12:

What I discovered just now is that I have too low voltage on the keyboard, 2.5V when it should be 5V 🙁

A short somewhere 😬

Ok, correction, it has 5V when the keyboard is not connected, and 2.5V when the keyboard is connected. I found similar thread here on vogons, where someone had same situation with keyboard leds.
After pressing any key which turns the led, the keyboard freeze. The problem there was a faulty transistor that connects the voltage. As newer keyboards (like mine), requires less power, they work, but as soon as some led is turned on/off it is not working any more.

Now, I would need to locate this transistor and check if it is faulty - If I only knew how... 🙁

pc keyboard bus is open-collector, looks like you shorted signal or clock to power?

rasz_pl wrote on 2023-12-30, 01:38:

pc keyboard bus is open-collector, looks like you shorted signal or clock to power?

If I did, then those pins would beep on multimeter, right?

Do a resistance measurement, not a continuity beep.

weedeewee wrote on 2023-12-30, 10:54:

Do a resistance measurement, not a continuity beep.

Between those pins?

Edit1:
DCC vs Data pin: ~ 16kOhm
DCC vs. clock pin: no connection, multimeter show 1
DCC vs. ground pin: ~ 16kOhm

Does it mean that data pin is shorted to the ground pin? If yes, where? I can only inspect the board from two sides, not some middle layer 🙁

Edit2:
I traced the data & clock wires and they do beep on kb controller, so that part should be fine. Power is also fine as I checked that before.
So only what is left is that there is indeed short somewhere, which I can't find. Also I noticed that it might be that I wired mouse voltage pin with inactive pin on kb. I cut that connection but result is the same.
Can it be that mouse is getting power from kb? Problem is that I torn wire traces, so not sure now what goes where.

I did some resoldering (had to build 2 traces) and even everything is fine, still no luck.
What I found this time to be very strange is that I have 0.9V on ground pin. I know that this is wrong but don't know how to fix it, when there are no any obviois shorts.

Doesnt look all that better 🙁
Buy flux, watch few soldering tutorial videos, get something modernish from recycle bin with multilayer PCB and practice on that until your soldering doesnt look like in those pictures 😀

as for this board - desolder PS2 connector, clean everything around, just for testing solder wires between pins of connector and pcb pads without fitting connector back to the board, that way should be easier - only two pins close to each other, you can get power/ground from molex or motherboard power connector

I'd advise against soldering anything at this point. the board looks burnt.

rasz_pl wrote on 2024-01-01, 15:00:

Doesnt look all that better 🙁
Buy flux, watch few soldering tutorial videos, get something modernish from recycle bin with multilayer PCB and practice on that until your soldering doesnt look like in those pictures 😀

as for this board - desolder PS2 connector, clean everything around, just for testing solder wires between pins of connector and pcb pads without fitting connector back to the board, that way should be easier - only two pins close to each other, you can get power/ground from molex or motherboard power connector

I have a flux, I just don't have much soldering skills. I know it looks ugly, but I just wanted to see if it will work or not, then I would take it to professional to solder properly. Don't want to pay if it will not work in the end. Some of the pins needed to be soldered as they are, as there were missing trace wires. Didn't quite get, what needs to be tested without fitting connector? Could you please explain again?

weedeewee wrote on 2024-01-01, 15:12:

I'd advise against soldering anything at this point. the board looks burnt.

Some of the damage was already there when I got it - someone maybe tried to fix it already.
But regardless, it is not working, so I can't loose anything if I try. If you can tell from the image that the board is burned, then I can give up, but is that the idea of the forum? This is not super huge important, it's a hobby. My idea is to share thoughts with people or get some good advice (like one before about soldering skills), but not just to give up on everything.

Well if you're all in for the board

Do tell, what soldering iron & solder are you using ? type, brand, power, ...

Also, it didn't look burnt in the first photo though it could've been the angle.

weedeewee wrote on 2024-01-01, 18:06:

Well if you're all in for the board

Do tell, what soldering iron & solder are you using ? type, brand, power, ...

Also, it didn't look burnt in the first photo though it could've been the angle.

Should be 750W here is the link:
https://amzn.eu/d/4VY02r9

Soldering wire is 0.6mm also bought on amazon

Yes, all the photos are taken with the zoom. It was like this from the beginning