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Computers that generally don't include an integrated display, and are meant to be stationary.

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Keyboard + mouse connectors problem

I got this PC Compaq Presario 7170, which had a problem with mouse port. It didn't work. Serial mouse is working.

I replaced both ports and soldered a new ones, but since then my keyboard is also reporting a problem on boot - Keyboard error. But it works. If I press any of the keys with led light (num pad, caps lock or scroll lock) keyboard stops responding. I need to unplug it and plug it back in to make it work again.

Even though my soldering is terrible, I checked all the leads and everything is connected. I also checked surrounding caps and resistors and they seams fine. At least, what I know to check.

Any idea where I could go next?

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Update (12/29/23)

Here is maybe better photo:

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Answered! View the answer I have this problem too

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Yes the new photo helps a lot! Sorry, but your solder connections look terrible. You may have a "cold" solder joint by looking at them.

I would neaten up the solder points by just touching it with the soldering iron until it flow and then slowly pull the iron away. Don't overheat and pull the iron away as soon as the solder flows. This could possibly be part of your problem ???

My motto is always look for the simplist solution first. You what is different and what did yo acyually do? You soldered so look there first.

It could be another component but start with the soldered connection.

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No need for sorry, I know it is terrible. My soldering wire was too thick, but now I got a better one.

If there is a cold soldering, it wouldn't beep from the conector till the wire on the board (where it is stripped). Soldering point is between those two

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Ok, so the problem was this component right here:

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The voltage was dropping on it, so I removed it (wire jumped) and now everything is working. Including mouse. :)

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Good. Well done.

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Maybe the solder is causing a minor short. Check with a multimeter but first clean up area on board. The photo is not very clear or my eyes aren't so good (grin). May sure the circuit board is clean around the solder points. Important - 99% (no water or minerals to short things) Isopropyl alcohol is good for cleaning. Are you sure it wasn't the mouse itself that was the problem rather than the port?

Of course the problem may be other components on the motherboard and it is close to 30 years old.

This site may help you better:

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Yes, I used IPA 99% to clean everything. No mouse was ok as it works on other PC and I tried 3 different ones. I checked each point and there is no short. Maybe I burned some component on the other side, but not sure where to look.

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I just discovered that I have 2.5V between DCC and ground pins on the keyboard connector. Based on the schematic, it should be 5V.

Could this be a issue and what can I do to track down this problem?

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Update: I have 5V when the keyboard is not connected, so that should be fine. But I red online that this could be due to faulty transistor that controls the voltage. Now I should find this transistor but I don't know how. :(

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Slobodan Maric will be eternally grateful.
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