leaking memory backup cells was"Re: [Kenwood] TS-850 Display Gone Wild"

[Eric Lemmon]

Avi,

It is surprising that some replies offer a definite solution to the leakage
problem without knowing what chemistry of coin cell is involved.  There are
basically two types of lithium coin cells:  "BR" types, which incorporate
polycarbon/monofluoride chemistry, and "CR" types, which incorporate
manganese dioxide chemistry.  The cleanup of leaking electrolyte is not the
same for both types.  The Panasonic lithium cell site may provide the answer
you seek:

<www.panasonic.com/industrial/battery/oem/chem/lith/coin1.htm>

Although the two types of lithium cells have somewhat differing capacities
and intended applications, it is not unusual to find the "wrong" type
installed in a particular radio, simply because it was the type available at
that time.

73, Eric Lemmon WB6FLY
 

-----Original Message-----
From: kenwood-bounces at mailman.qth.net
[mailto:kenwood-bounces at mailman.qth.net] On Behalf Of Avi - Modi'im Orchards
Sent: Tuesday, December 18, 2007 11:23 AM
To: kenwood at mailman.qth.net
Subject: leaking memory backup cells was"Re: [Kenwood] TS-850 Display Gone
Wild"

The two answers I got are a bit different. Clif at Avvid suggests 100% 
denatured alcohol, and Ken KD0AGV suggests baking soda (and BTW warns NOT to

use alcohol - I would gues this is dependant on the kind of alcohol and the 
material from which the substrate of the circuit board is made).

The first answer implies that the pollutants released from a leaking button 
cell are basically organic compounds that need a solvent to be removed, the 
second that they are acidic and need to be neutralized by a base. Sometimes 
the salts that are formed in these acid-base reactions can have their own 
negative effects, too. Are there any chemists on the list who can enlighten 
us as to what the nature is of the stuff leaking from a spent button cell, 
how they would handle the cleanup without endangering the copper traces or 
circuit board substrate or plastic housings of adjacent components, and BTW 
if there are any health hazards involved?

 -avi 4X6UA

P.S. - i'm purposely leaving the chain of messages below because I changed 
the subject header.

----- Original Message ----- 
From: "Avi - Modi'im Orchards" <tiavi at netvision.net.il>
To: "Clif Holland" <clif at avvid.com>; <kenwood at mailman.qth.net>
Sent: Tuesday, December 18, 2007 09:03
Subject: Re: [Kenwood] TS-850 Display Gone Wild


> What technique or material do you recommend for removing and neutralizing 
> the chemicals from battery leaks on PCBs?
>
> -avi 4X6UA
>
> ----- Original Message ----- 
> From: "Clif Holland" <clif at avvid.com>
> To: "Henry" <ka3muf at charter.net>; <kenwood at mailman.qth.net>
> Sent: Tuesday, December 18, 2007 03:47
> Subject: Re: [Kenwood] TS-850 Display Gone Wild
>
>
>> You need to get your nose in the radio "RAT NOW", that's immediately for 
>> those furthur north.
>>
>> Odds are pretty good the battery is leaking and there are data lines 
>> under it that don't like battery acid. The longer you wait the more 
>> damage.
>>
>> Remove the top and bottom.
>> Remove the top screws on each side just behind the front panel. (2).
>> The front will tilt over and the battery will be just to the left of 
>> center on the board on the chassis.
>> Look around it for any signs of white powder. Tilt the top of the battery

>> over and look behind it. Us a small flashlight. Any signs of white power 
>> and it's leaking. Look closely at the seam on the back. Look the entire 
>> board over carefully for any corrosion etc.
>>
>> That's the digital unit and they are no longer available so don't damage 
>> it or you have a trotline weight.
>>
>> Clif Holland KA5IPF
>> www.avvid.com
>>
>>
>>
>>
>> ----- Original Message ----- 
>> From: "Henry" <ka3muf at charter.net>
>> To: <kenwood at mailman.qth.net>
>> Sent: Monday, December 17, 2007 5:14 PM
>> Subject: [Kenwood] TS-850 Display Gone Wild
>>
>>
>>>I know that something about this problem has been posted previously but I
>>> have been unable to locate it.  The radio still works and I have gotten 
>>> it
>>> to display the desired freq. on 75 meters but when it was first powered 
>>> up
>>> today, every item in the display was illuminated and nothing but 8s and
>>> sometimes vertical lines were displayed in the frequency area.  Is my
>>> internal battery going south or what?  I tried the hard reset which 
>>> seemed
>>> to work but the same erratic display appeared after turning the VFO.  A
>>> little more patience and now the display seems to be stable.  I am 
>>> however,
>>> afraid to turn the radio off!  Is there a quick and easy fix for this? 
>>> If
>>> the battery needs replacing, can this be done by me with relative ease?
>>> Something tells me the battery is well buried in the bowels of this 
>>> great
>>> radio!!
>>>
>>>
>>>
>>> This is my first posting here so hopefully no ones feathers are ruffled.
>>>
>>>
>>>
>>> Henry KK4HG
>>>
>>> 276-608-8750

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