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*ElectronicsTech, Customer Service
Category: Electronics
Satisfied Customers: 10284
Experience:  I have over 15 years experience as an electronics repair and troubleshooting technician.
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my siemens gigaset SL785 cordless phones will not charge and

Customer Question

my siemens gigaset SL785 cordless phones will not charge and all three handsets go dead after about one minute
Submitted: 3 years ago.
Category: Electronics
Expert:  *ElectronicsTech replied 3 years ago.

Hi Karl,
My name isXXXXX will assist you.
I am sorry to hear that you are having this issue. Try this on each of the handsets please>

  • Unplug the power-supply unit from the socket.
  • Press and hold down the paging key on the base station.
  • Plug in the power-supply unit again.
  • Keep the paging key on the base station pressed.
  • Release the paging key after 3 seconds.

PLEASE NOTE! The entire contents of the memory will be deleted. All portable handsets will be deregistered. The system code will be reset to 0000.

Please let me know if this does not work or if you need any other assistance.
Please take a moment to rate my service positively.
Thank you very much!

Customer: replied 3 years ago.

Hi randy unfortunately this did not do anything mate

Expert:  *ElectronicsTech replied 3 years ago.
Okay, I am sorry to hear that. I am thinking that this is a firmware issue rather than battery related because of this occuring on all of your handsets. It could possibly be the main base as well. The main base could be causing the handsets to shut off. Lets try updating the handsets next with the Gigaset QuickSync program using your PC.

To enable your handset to communicate with the PC, the Gigaset QuickSync program must be installed on your PC (free to download at

The firmware-update of handsets is only supported by Gigaset QuickSync for Windows. The Gigaset QuickSync for MacOS supports only the firmware-update of the SL910H.


Please make sure that you use the USB cable to connect the handset that you want to update, as updating via Bluetooth is not supported!


If your handset is updatable and your PC is connected to the Internet, Gigaset QuickSync will automatically check for new firmware at least once a day, and if it is available it will prompt you to update your handset. You may disable this feature by unchecking the “Check Internet for new firmware and notify if update is available." checkbutton on the Settings - Firmware... page. It can also be disabled via the appropriate checkbox when Gigaset QuickSync prompts you to update your handset.


You can always trigger the facility to check the Internet for new firmware manually:

  • Connect your phone to your PC using a USB data cable.
  • Start the Gigaset QuickSync program on your PC.
  • Establish a connection to your handset.
  • Click in the main menu of QuickSync on Firmware update.

This launches the firmware update. The update process can take up to 10 minutes (not including the download time). Do not interrupt the process or remove the USB data cable. The data is initially loaded from the update server on the Internet. The amount of time this takes is dependent on the speed of your Internet connection.

The display on your phone is switched off and the message key and the talk key start flashing. Once the update is complete, your phone will automatically restart.

Customer: replied 3 years ago.

hi Randy tried the firmware update even borrowed a windows machine to do it but still no luck

Expert:  *ElectronicsTech replied 3 years ago.

okay, does the battery indicator show on any of the handsets?

Battery charge status:
outside the charger white: charged over 66 %
white: charged between 33 % and 66 %
white or red charged under 33 %
flashes red: battery almost empty (less than 10 minutes talktime)
in the charger white: battery is charging
Try this on the base please>
Disconnect the power cord from the base
station. Hold down the Registration/Paging
key on the base station while reconnecting
the power cable to the base station. Release
the key after a few seconds.
Then try and register one of the handsets>
Customer: replied 3 years ago.

Hi Randy done as asked and phones will not register all of them come up no base. when the phones are in the cradles they appear to be charging.

When I press the the paging key on the base station nothing happens i have checked the power supply and it is ok

Expert:  *ElectronicsTech replied 3 years ago.

okay, unfortunately that sounds like the base has failed and will need to be replaced.