I have a General Electric and a Radio Shack kitchen radio. These radios are very sensitive and have
a no nonsense sound profile that makes them ideal for shop radios. In addition, they have
a timer with a 1250 watt relay controlled outlet.

The problem is they eat the batteries used for clock backup. Has anyone come up with a clever
work-around using a rechargeable drop in replacement for the 9 volt battery? The early clock
ICs were not like watch ICs today. The GE model blinks 12:00 , fluorescent display, and the
Radio Shack howls, with a dead battery after a power blip.

Post a schematic and we'll see what can be done. I'm thinking about a zener diode circuit.

~ Mitch ~

I have a Proton 320 clock radio from the 1980's and it will use up a 9 volt backup battery in 8 hours if the radio is left unplugged. If I have to unplug the radio for more than a few minutes, I disconnect the 9 volt battery. In normal use the battery lasts for several years.
Don

The life in the Radio Shack radio is about a year, The GE is less. What I will do is measure the current
during power-on , and power off. The same issue is in telephone answering units and scanners here.
The TADs have a strange current curve on the battery backup.

This never was an issue when Radio Shack gave you a battery a month free with the battery-club card.

What I hope to do is make a circuit that, A. informs the logic that a battery is there, and B. Balances the
battery on continuous float. Those old clock chips are pigs though, just to keep it ticking even though the
display drivers are not needed. The General Electric processor, also switches the tuner logic from AM to FM and
turns the radio on and off.

This is known as the "blinking 12" syndrome, usually associated with 1980's era VCR's, and is an easy fix.

Get a strip of black electrical tape, cut to the length of the readout, and apply over it.

I assumed the battery lead had a diode, so when the radio was plugged in, the power supply fed the clock, and had a higher voltage than the battery so the diode isolated it. The radio is always warm! The clock chip used the 60 Hz line for timing, and when on battery power the time drifted a LOT on the Proton 320.
I have an answering machine that is like a mechanical clock, the time stops and resumes when power is restored, so if the power is off an hour, so is the time. My new one with Caller ID sets the correct time with each incoming call.
Don