What zener diode might fix the sound on Maestro Mayhem gaming chair?

[nev1001]

Hi, I'm looking for a bit of help trying to fix the audio unit from a Maestro Mayhem 4.1 gaming chair please.

The chair has a few speakers and vibration motors. All was well, for a while, but now the sound is gone.

It may be significant that I discovered my son was powering it with a 19V laptop charger when it should run on 12V - it did fully work, for bit.

I think an issue could be a zener diode (or capacitor) which has shorted out.

The board's bluetooth input still works, the vibration motors are working, so is the line out socket but not the speakers - there's no output from the headphone jack either.

I believe a symptom is three amplifier chips are not getting any power. There are also two blue LEDSs which don't work and they seem to trace back to an area of the board which was under a burnt looking blob of glue.

I think I can also trace a path to a transistor (? in the red square), labeled 6098 1808P. And that transistor controls the voltage to the amplifiers??. There is 12V on the top leg of the transistor but 0V at the amplifiers.

I think this little circuit is the burnt bit of the board. I can measure 12V across the resistor and nothing across the Zener/capacitor. I think the Zener could be shorted (or the capacitor or both?)

12V
|
|
R 100 ohms (I think!).
|
|_ _ _ _ _ ______ _ _ ?? V
|         |
Zenner?  _|_
|        ___   100 micro farad 16V
|         |
------------- ground

I'm guessing if you plug in a headphone jack it should cut the sound to the speakers, but that part of the board is not working - so no sound at all?

I don't know if it additionally helps but two of the amplifiers are labelled TEA2025B WX 1902TN and the transistor 6861 1808P. I could google info on the amplifiers, but not the transistor and nothing for any other numbers/codes on the board.

Any suggestions please - is the problem maybe with the zener diode? if so what to try 3.3 V or less, because it feeds some LEDs-?

[CapLeaker]

I think that SMD device next to the diode is a resistor (101?) Measure that zener diode with your DMM. Is it shorted? Maybe that zener is still good… we don't know that yet.
There are also a few small 16V capacitors that look not too good (looks like the sleeve shrunk?)
The CED6861 is a P channel enhanced FET. If there is nothing on the gate, no power will go through it either.

[nev1001]

Ah, thanks. Actually the zener could be ok as suggested. I tested it, still on the board, with my basic DMM and it seems ok, the same as others on the board when I compare.

I will get some replacement capacitors and try replacing the first one and see...

[CapLeaker]

Look at that resistor next to that zener. That looks cooked to me. I think it has 101 printed on it, that should translate to 100 ohms.

[petehall347]

looks hot here

[nev1001]

Thanks I will try to get a replacement 100 ohm resistor too.
That brown patch is on the heat sink over the two amps, I guess it was some glue?