Below is my successful attempt to solving this issue, [ thanks for pushing me Zaba :-) ] fast and easy to made but of course, be warned :
Any mistake can cause serious damage to your radio. So if You are not experienced in SMD soldering or using soldering iron at very FRAGILE environment - do not try to perform the operation! I will be not responsible for any damage You can make doing the MOD.Start with placing the RIG upside down and unscrew bottom cover.
You'll see whole radio - take look at lower right part marked by red arrow.
In next steps we will replace it with ordinary CR2032 Li-Ion battery.
Start with preparing new battery socket. No matter new or salvaged from old PC motherboard, any type will do. And of course we'll need CR2032 or similar battery. It's not critical what type of battery we'll use, except it's 3V one. Standard PC clock battery is thousand more times capable than factory one.
Next - prepare some wires and solder it to the socket.
Battery pads cleaned after removal
Now we are ready to install new battery. In my radio I did it this way - socket is glued safely with double sided adhesive tape onto uPC. Do not put the battery first. In case something is wrong this could damage your radio. After soldering the wires and checking for any short circuit, mistake with polarity slide the battery into socket.
This operation completes the mod. No more clock failure, at least for next 5-10 years :-)
73, QSH / OCV