[ICOM] Encoder for IC751A - main tuning

[Don]

I changed the original battery in my 751A after 17 years -
was still ok but I installed a third party 
replacement module as a precaution.
Don 
K1AC

-----Original Message-----
From: icom-bounces at mailman.qth.net
[mailto:icom-bounces at mailman.qth.net] On Behalf Of Gary P. Fiber
Sent: Thursday, March 06, 2008 10:49 AM
To: ICOM Reflector
Subject: Re: [ICOM] Encoder for IC751A - main tuning

YOUR RIGHT Lee..
My own fault for thread drift. The IC-735 however does not have that
issue

Where the IC-751, 751A, 761, 271, 471, 1271, M700, M700TY and R71A
all 
utilize the battery backed ram unit. My own experience when working
at 
Icom was that ram units battery generally did not fail until someone

messed with it trying to change out the battery. We did see cracked 
solder joints on the untis connectors though. Likely due to heating
and 
cooling over the years. The ram unit's current requirements is 
micro-amps range well within the lithium's battery to keep the ram
unit 
alive for many many years.

Third parties are making replacement modules now days and adding
things 
like expanded memories to them too. I am glad the UX-14 has been 
duplicated as those with faulty encoders can still use the 751 via 
computer control.

For most Icom's a rule of thumb is if the battery measures 3.0 Volts
DC 
its generally good. Some of the handhelds before the eeprom,
utilized a 
rechargeable lithium battery. The 2SAT series did that along with
the 
P2AT. That rechargeable lithium battery in the 2SA and others series
was 
recharged from a fully charged battery pack.

Gary K8IZ

Lee Mairs (SAG) wrote:
> I guarantee that if you remove the battery from the IC-751A it
forgets 
> completely that is a radio!  Don't ask me how I know this, but
there 
> was a company that sold a replacement module that "hard wired" the

> requisite code in ROM so that you didn't have to worry about
changing 
> the battery.
>
> DO NOT attempt to change the battery on an IC-751A without a
parallel 
> voltage source!
>
> 73 de Lee
> KM4YY/8
>
>
>
> Jim Hargrave wrote:
>> Gary,
>>
>> I hope you are right. I have been led to believe it also powers
the 
>> CPU to
>> retain some of the programming information. If it only holds the 
>> memories,
>> that might explain the long life without any failures. I only use
the
>> memories for band switching and have never found them empty.
Maybe 
>> I'm just
>> lucky.
>>
>> * 73's Jim W5IFP *
>>
>>>  -----Original Message-----
>>>  From: icom-bounces at mailman.qth.net
>>>  [mailto:icom-bounces at mailman.qth.net]On Behalf Of Gary Fiber
>>>  Sent: Thursday, March 06, 2008 4:08 AM
>>>  To: ICOM Reflector
>>>  Subject: RE: [ICOM] Encoder for IC751A - main tuning
>>>
>>>
>>>  Jim,
>>>
>>>  The IC-735 memory battery ONLY backs up the 10 memories nothing
else.
>>>  Worse thing that will happen if the memory battery goes dead in
an
>>>  IC-7355 is all the memories will reset to 28.000 MHz
>>>
>>>  Gary K8IZ
>>
>> ----
>> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
>> Icom Users Net: Sundays, 1700Z, 14.316 MHz
>> Icom FAQ: http://www.qsl.net/icom/
>>
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
>

----
Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
Icom Users Net: Sundays, 1700Z, 14.316 MHz
Icom FAQ: http://www.qsl.net/icom/

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