New memory baterey for a TW-4000A

[vulogov]

Is anyone had success to replace memory battery for 80-th Kenwood TW-4000A ? I would appreciate some guidance or HOWTO I shall perform this operation.

Thank you.

[K9YLI]

If its like most Kenwoods. If you can find it. just get a battery from a battery vendor. In the US you can get battery with out solder tabs at drug stores and watch battery places.
or in US , batteriesamerica and other places etc have batteries with tabs for about 3 dollars.
Draw a picture before you de-solder the old battery to get polarity correct. i have put in backwards and the only problem is memory still doesnt work. Correct the problem and battery etc are all ok.
don..

[vulogov]

I opened top and the bottom covers, but sadly did not find anything looks like a battery matched a pictutre in the manual. I maybe needed to proceed to the next layer of boards. The indications are, when I first time turned radio on, everything working flawlessly. Then after a 1/2 day in the car (not too cold day I shall say), it become strangely inoperative. VFO did nt working, but I were able to select MR and perform search. Another 1/2 day and power on, but none of the buttons and knobs are having any effect. I can see only backlit. Voice circuit (the one which tells your frequency and other status) do not works ether. Manual suggests, when memory baterey becomes bad, random behavor may occurs. Do you think this is the case ob bad baterey ?

[K9YLI]

Usual case of bad memory battery is when you shut radio off , the next timeyou turn it on the memorys are gone and dial shos up at beginning of band.
In the case of a 2 meter rig they power up to 144.000.

if you have other problems, I would not concentrate on the back up battery.
which is likely located on one of the PC boards. battery is about the size of a quarter. 3.0 volt.
I would start checking ground leads and power to radio.
check with voltl meter from chassis of radio to steering wheel ground. (darn plastic cars) The steering shaft under the dash is likly a good ground reference.
any voltage from chassis to ground would indicatea bad or feeble ground to chassis.
thurough check of power and ground leads.
if possible take in house and run off power supply or battery. easier to work on then under dash.
SEPERATE AND SUBSTITUTE is how to fix things.

substitute other power source. other lead wires. other antenna. other speaker, take notes as to what works every time.

[K9YLI]

editted out dup post. to save space