(translated with use of internet).
A while ago, our Samsung Soundbar HW-H750 suddenly stopped working. The bass speaker was still working (wireless), but the soundbar itself did not make a sound. However, the display worked and could also be operated via the remote control.
Fortunately, I found a service manual on the internet.
But then the search for what exactly was wrong began. After some searching it turned out that the -24V no longer worked. A miniscule fet seemed to be brooken.
However, attempts to replace it did not work out well, the housing of the fet and pcb did not allow me to solder them properly.
The search for a new print was also negative, no longer in stock.
She was put aside but recently brought back up. To eventually also become a recovery.
First the focus was on restoring the print, now I had another idea, adding an extra power supply.
First, the PCB was stripped of all components that provided the -24V. Then a connection was made with a normal power supply (+ to ground, minus at a -24V point of the pcb).
For example, it could be checked whether this would work and if so, to see how much power the circuit needed.
It turned out that the -24V did not need much power.
To supply the -24V, an adapter of 24V was used. Since the current is not that high, it is quite small. The -24V is not always present, to be able to switch off the connection to the power supply, a read relay is provided. This is switched by the voltage that normally supplied an IC with power when the amplifier was switched on and -24V was required.
