Battery not lighting digital clock

Hi @brucenewjersey ,

Has it ever worked OK when on batteries only?

Don’t know the clock and I can’t find a user manual for it but with a lot of clock radios the device doesn’t work when on batteries only as the batteries are only a power backup to maintain the time and hold the alarm settings in the event of a power failure. Usually there is no time display shown and the radio also doesn’t work so as to minimize the power drain on the batteries. When the power is restored it means that you don’t have to adjust everything back to what is required.

Check if this is what happens with your model when you turn off the AC power with the batteries inserted.

Without the batteries inserted all the information is lost and normally when the AC power is restored, the time blinks on and off, indicating that power has been lost and it needs to be reset to the correct time

If it is supposed to work on the batteries only then you need to check the circuit from the battery terminals to where the output from the AC power on the circuit board is rectified to DC voltage to run the clock, as there must be a problem between those two points.

The AC power will be rectified to the same DC voltage value as the DC battery supply. Once it has it is the same circuit for both power supplies.

I’ve found a service manual for the clock/radio (or at least I hope it is a service manual and not a user manual) that may help as it should have the schematics. The downside is that you have to pay for it.