Derek Toeppen wrote:
I have a 13 year old IC735. In the manual it says the
lithium battery is good for 5 years. After that it
should be monitored closely and replaced as needed.
The battery has not been changed in the 13 years.
So I am thinking its time to replace it.

The manual says it is used for the memory that
holds the frequencies and setup. And that it should
be replaced by Icom. At this time the radio remembers
all the setups and frequenies when powered down. So it
appears to still be functioning.

What happens if I remove the battery with the power
off? Do I loss just the setup? Or do I loss the operating
system for the radio?


I am going to make an assumption that this is the same or similar setup
that is used in the IC-745. I had one several years ago and changed the
battery and you really need to be careful. You should get a 3 volt
source and tack solder it across the points on the circuit board where
the existing lithium battery is connected. You may want to do the tack
soldering on the same circuit trace but away from where the lithium cell
is soldered in. Remove the lithium cell and replace it with the new
one. Then remove the tack solder leads and you should be set for
another 10 years or so. If you remove the lithium cell without the
backup, you will lose the radio programming and it must be sent back to
Icom for reprogramming. If you do blow the programming, you need not
send the entire radio (at least on the IC745). As I recall, the memory
board is socketed into the main board so all you need send back is the
memory board.

I went to Radio Shack and purchased a two AA cell battery back, soldered
the leads onto that with some fresh AA's and the battery replacement
went just fine. It is quite easy to lose the programming though. A
good friend of mine, who is a very meticulous technician, lost the
programming on his IC745. Perhaps his solder connection wasn't good or
he lost the memory voltage for a split second, but he had to send the
memory board back to Icom.

If your radio is 13 years old and the memory is on the same battery, I
would definitely make arrangements to replace that battery.

Andy
WD4KDN


--


"People sleep peaceably in their beds at night only
because rough men stand ready to do violence on their behalf."

George Orwell