I recently encountered a Yamaha PSR-S750 with a couple of issues that appear to be quite common in this series. I wanted to share my experience in the hope that it might help someone in the future.
Sudden Shutdowns
The customer initially reported that the keyboard would display an error message at irregular intervals and then require a restart. This issue turned out to be related to a known problem with the main DM board. Apparently, early versions of this board have a tendency to delaminate, leading to errors such as the following:
“Unexpected error! Turn the power off and on again.”
However, the board can fail in various ways, including issues with powering on, sudden shutdowns, and more. The recommended solution is to replace the DM board (part #WZ353701). Unfortunately, this is not a cheap fix—the part currently costs around $503 on Full Compass (as of August 2024), though a Yamaha service provider may be able to offer it at a lower price.
Keyboard Turns On but Won’t Turn Off
This is an interesting issue. The power switch on this keyboard is a rubber button that, when depressed, completes a circuit to ground. Over time, as the button ages and the graphite on its underside degrades, it does continue to complete the circuit, but the resistance increases. Eventually, this high-resistance path is enough to signal the keyboard to turn on, but not enough to signal it to turn off. Diagnosing this issue can be tricky because the button consistently powers the keyboard on, even though it is the source of the problem.
The replacement button is part #WZ960401. Replacing it involves removing the entire front panel, making it a somewhat involved process. It would be wise to have a copy of the service manual on hand before attempting this repair.
Notably, the same issue can occur in the PSR-S770, PSR-S950, and PSR-S970.
Finally, make sure to update your Yamaha PSR-S750 to the latest firmware! Download the latest firmware file, put it on a USB stick, and insert the USB stick into your PSR-S750. Then Power On the keyboard while holding the Start/Stop button (below the LCD screen). You’ll be guided through the update.
For more on digital keyboards, see my Digital Keyboard FAQ.
Hace unos días, mi teclado Yamaha PSR S750 mostraba el error “Data Flash Rom Device Error”. Restablecí la configuración de fábrica y luego actualicé el firmware, y funcionó; el error desapareció. Pero dos días después, el teclado se bloqueó por completo. Ninguna tecla ni botón de función funcionaba. Seguía encendido, pero nada funcionaba. Lo desconecté y ya no enciende. No sé qué hacer.
Estos síntomas son algo preocupantes. Parece que la placa principal (DM) podría estar fallando, y que el restablecimiento de fábrica y la actualización del firmware solo te dieron un poco más de tiempo. Dado que el PSR-S750 fue fabricado alrededor del año 2012, los problemas de hardware relacionados con la edad son bastante probables.
La buena noticia es que todas las piezas —incluida la placa principal— todavía están disponibles para el PSR-S750. Te recomiendo que lo haga revisar un técnico local autorizado de Yamaha. Puedes usar la herramienta de localización de servicios de Yamaha para encontrar un centro de servicio cercano.
This is the English translation of my response:
These symptoms are a bit concerning. It sounds as though your main (DM) board might be failing, and that the factory reset and firmware update only bought you a little extra time. Since the PSR-S750 was manufactured around 2012, age-related hardware issues like this are quite possible.
The good news is that all parts — including the main board — are still available for the PSR-S750. I recommend having it inspected by a local Yamaha technician. You can use Yamaha’s Service Locator tool to find an authorized service center near you.