No sound when pressing the ears - pin defects on PCB

[ToMyKnock]

Hello family ,
just got a toniebox from a friend where the big ear is not working anymore - no sound at all when pressing. When pressing the small ear there is also no sound, but the green LED is glowing brighter after pressing the ear.
Both ear switches are working well - tested it.
TB is playing every tonie i put on the box - only very quiet - think the volume is on the lowest level.

After opening the box and get out the PCB i found this:

I think this is a kind of dry foam - maybe toothpaste. After removing with isopropanol it is looking like this picture:

i found three pins where the gold contact is removed - no contact at all to the backside of the PCB.
I think the liquid destroyed the pins and after removing the “foam” they peeled off.

What do you think:

• Just make a contact with solder wire (Fädeldraht) from the back side to the front side of the PCB will help?
• Is the PCB just a two layer PCB?
• Any other ideas to get the ears working again?

Thanx for your ideas and help so far

Greetings Matthias

[Andrew_Bellott]

So im unsure of if its more than a 2 layer board bit i would assume not. For the contact closest to r390, im thinking thats just a ground. I would need to see the other side to verify but yeah. The contact closest to c84 i would run a wire from the other side, and the remove some of the solder mask on the trace and attach there. Same for contact near r392. Hope this helps.

[m_hans]

I experience the exact same issues (ears not working anymore, Tonies play but with low volume) after replacing the ears. When replacing I removed part of the PCB surface. With help of a local Repair Café, we fixed this - at least the button press of the ears closes the circuit. Measured also against some other ground pins.

Is there a way to check if the ears are connected to the controller (?) on the board as they should be? Is there a schematic or layout of the pins so I know where to measure with the multimeter?

Any suggestions would be appreciated.
BR
Georg

[0xbadbee]

@ToMyKnock

Is the PCB just a two layer PCB?

The toniebox is 4 or 5 layered

The ground of the ears lies under the connector and goes to R56. So please first of all check if the middle pin of the ear connector is connected to ground (red)

@ToMyKnock

Just make a contact with solder wire (Fädeldraht) from the back side to the front side of the PCB will help?

If the vias isn’t contacted any more, this may help. But be sure you are only connecting things that should be connected. The toniebox-pcb repo may help you with the TPs.

[m_hans]

Hi, thanks for the hint to the github PCB repo.

I now measured and have connections between pink and read, yellow and red (when big ear is pressed only), green and red (when small ear is pressed only) and between yellow/green and TP26/TP31.

Still, the issue with the buttons not working prevails. No sound on press, no wakeup on press. No change in volume.

What more can I do?
I have images of the board if that helps…

Thank you and BR
Georg

[0xbadbee]

Did you check if the middle pin is connected to ground?

[m_hans]

Yes, can confirm. (Almost) any of the free ones on the side with the Tonie Icon works.

[m_hans]

@ToMyKnock Did you somehow solve this?

[ToMyKnock]

@m_hans sorry for the late answer today.

yes, i got this toniebox repaired with the mentioned “Fädeldraht” and with conductive silver paint.

Greetings ToMyKnock

[m_hans]

Thank you for the update. In my case, the contacts you fixed look fine. So I am not sure if that would help in my case. I cannot see the Fädeldraht, how exactly did you connect front and back of the PCB?