After many years of operating the CMOS battery needs to be replaced.
CMOS = complementary metal-oxide semiconductor
A complementary metal-oxide semiconductor (CMOS) is the semiconductor technology used in most
of today's integrated circuits (ICs), also known as chips or microchips. CMOS transistors are based
on metal-oxide semiconductor field-effect transistor (MOSFET) technology.
Why? The question could be asked…
The radio is dependent on Custom settings and sometimes when the battery runs out of
power, the radio does not keep the settings.
PLEASE NOTE: When removing the battery you will lose all the settings. Make
sure to write the settings down.
The process below is not a complex one rather a normal repair process with not a high level
of skills.
Tools require for the replacement:
“Star” Philips Screwdriver
Flat tip screwdriver
Soldering iron
Soldering Flux
Soldering wire
Pair of Pliers
2 pieces of wire RED (+) and BLACK (-) Length of wire depends where
you are going to place the backup battery.
Self Adhesive tape
Small container to keep screws together
Process:
Take bottom and top cover screws out and remove covers.
At the side of the Front cover you will find 2 screws each side which has to be removed.
The battery will be visible on the panel.
The battery (if available) can be replaced with a standard battery or could be replaced
with a “modified” setup.
In this guide it was replaced with the “Modified” one.
Desolder the battery from the board.Make sure that the soldering points are still in
good condition. Do some cleanup and apply an additional “blob” on those points.
To be able to fit the modified battery it was necessary to print a cage for the battery.
Here is the link to the battery holder 3D printer files. Click HERE.
I bought the battery from a Security company selling Security equipment
I used some scrap material to fit a plate to the POS and NEG of the holder. Next you
have to solder a black wire to the Negative and RED wire to the Positive end.
Find a place where the battery could be fitted (I used self adhesive tape) inside the radio
or somewhere near the original battery.
Just next to the original battery was the most convenient place to fit the complete unit
(Battery). Note the position of the RED and BLACK Wire.
Finally, I use a piece of Duct Tape to ensure the battery stays in place.
Assemble the radio and test.
Please remember to restore all the settings Previously made by you.
Enjoy!
ED. Curtis thank you very much for this informative and useful article. I am
sure that many Kenwood TK80 users will benefit from it. So no excuses. Replace
that flat CMOS battery if yours has been flat for some time.
