Go Down

Topic: Trying to repair HDMI connector on laptop motherboard (Read 993 times) previous topic - next topic

NissanCedric

Oct 24, 2019, 12:14 pm Last Edit: Oct 25, 2019, 03:04 am by NissanCedric
My laptop's HDMI connection failed and I'm attempting to repair it by replacing the socket. Not easy.

I was using an external monitor with the video cable connected to the laptop's mini HDMI socket. It started failing (complete loss of signal) & by jiggling the cable at the socket I was able to find just the right spot to restore the signal. It got progressively worse till I could not regain the signal at all.

I de-soldered the socket from the motherboard & soldered in a new one. You only solder the socket body to the board at four points, you don't solder the signal connection wires. They simply press against the tiny pads on the motherboard (about 20). Clearly the socket is installe by a precision CNC machine at manufacture & it's not easy to do manually and by eye. The pads and wires are tiny and at a small pitch.

HDMI connection at lower right:


The new socket doesn't work. Looking at the pads thru a magnifier, they appear okay. Thru a microscope attached to my camera phone they don't look so good. There appears to be material bridging some pads, perhaps metal.

under UV light:


In the following pic you can see a distinct arc pattern across the pad area, perhaps metal particles. I'm thinking this might be the outcome of my jiggling the plug over  a long period of time.

under white light :


Has anyone had experience repairing such a socket?
Any suggestions as to how I cud clean the pad area of the debris?
What are my chances of success?

Thanks,
John.

Paul__B

You only solder the socket body to the board at four points, you don't solder the signal connection wires. They simply press against the tiny pads on the motherboard (about 20).
Sorry, simply wrong!

Your jiggling fractured the solder bond. :smiley-roll-sweat:

One of the limitations if "lead-free solder".  :smiley-eek:

Wawa

Has anyone had experience repairing such a socket?

Any suggestions as to how I cud clean the pad area of the debris?

What are my chances of success?
Yes.

Set your temp controlled iron to 200C and solder a big blob of fresh solder on all the traces (shorting all of them).
Common resin-core 1mm will do.
The low temp won't burn off the flux from the fresh solder.
Now you can just swipe the blob and the crud off with the soldering iron, leaving a small amount of solder on the clean pins and plenty of fresh flux between the traces. It helps if you clamp the board in a small vice, and angle it a bit so the solder can run off.
Set your iron to 240C, and solder the new connector pin by pin (not adding any new solder).

Mine, 100%. Yours, dunno.
Forget about it if you don't have a temp controlled adjustable solder station.
Leo..

NissanCedric

Paul n Leo.

Thank you.

So I misread the situation and the pins were soldered to the pad. That's good news, but I'm daunted by the job of re-soldering them.

Leo, I do have access to a temp controlled iron. Will give it a go and let you know.

John.

SteveMann

Don't 'wipe' the pins with the iron- you risk throwing tiny blobs of solder elsewhere on the PCB.  I just solder the pins, don't worry about bridges between pins.  Then follow with a solder wick.  The wick sucks up all the excess solder on top and leaves the solder beneath the pins aone.

And stop "jiggling" the connector.
Please do not ask for help by PM. I will not respond.
If you need help, post a question on the appropriate forum.

Wawa

No solder balls are made there if you use a low temp and wipe off slowly.

Don't use solder wick either. That will usually damage traces.

If you have bridges, then you were using too much solder and not enough flux.
High iron temps burn off flux fast. Must use adjustable temp control for fine work.

If you do it the way I told you, you won't have problems.
I often use/replace dozens of fine-pitch processors and connectors a day.
Leo..

Paul__B

The USB connectors on Nanos are a problem, soldered with rubbish lead-free solder!

Once the frame solder points come loose, that's it!

NissanCedric

#7
Oct 26, 2019, 11:00 am Last Edit: Oct 26, 2019, 11:12 am by NissanCedric
And stop "jiggling" the connector.

Indeed.

This has caused me such a headache that I now religiously plug & unplug all connectors on all devices straight in and out.

I have much trouble with USB connections as do other people. General consensus is that cheap cables are the culprit. But I wonder...are the internal pads and wires being gradually degraded?

Paul, is it practical to add leaded solder to the frame connections before any trouble starts?

John.

Paul__B

Paul, is it practical to add leaded solder to the frame connections before any trouble starts?
Precisely as I have done wherever I can.  :smiley-lol:

Go Up