[time-nuts] SRS SR620 counter problem/Battery

[Brian Kirby]

I had a problem with a Z3801A GPSDO.  I added a backup battery to the 
Motorola Oncore VP receiver, so it could store GPS satellite almanacs 
(makes the unit come up a lot faster from an unpowered state).  I used 
common 1.5 volt AA alkaline batteries, two in series to the receiver. 
Worked great.

The Z3801A started losing lock at random and when I was around to 
witness it, it was the GPS receiver.  I opened the unit up to check it 
and found one of the batteries had leaked and was corroding to the other 
battery lead.  I cleaned the corrosion out and replaced the battery 
holder with another holder, and new batteries and the unit is back up solid.

I had dated the batteries, they were over 7 years old, and they were 
dated to "expire" in 2008.  Of course, I could not see that from the 
outside of the box.

Brian - KD4FM

On 10/25/2010 7:41 PM, paul swed wrote:
> Suggest a 100K thats 33 ua and at least 10 to 60 X more then the memory
> draws.
> Memories in standby draw 1 ua or even far less these days.
> The fact that the battery is at 3.44 and 3.2 suggests it may be fine.
> I just repaired the front panel of a sig gen and the diode was shorted
> draining the battery to zero because it was feeding lots of other stuff.
> Gud luc
> Paul
> WB8TSL
>
> On Mon, Oct 25, 2010 at 7:32 PM, J. Forster<jfor at quik.com>  wrote:
>
>> Certainly could be, but it seems a reasonable first thing to check before
>> tearing into the unit.
>>
>> FWIW,
>> -John
>>
>> ==============bv
>>
>>> I expect that it is a Lithium cell, so the voltage is correct. Although,
>>> testing it with a 1K load may not be fair as in real service I believe
>>> they
>>> only provide microamps. Regards - Mike
>>>
>>> Mike B. Feher, EOZ Inc.
>>> 89 Arnold Blvd.
>>> Howell, NJ, 07731
>>> 732-886-5960 office
>>> 908-901-9193 cell
>>>
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>>> Behalf Of J. Forster
>>> Sent: Monday, October 25, 2010 7:18 PM
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] SRS SR620 counter problem
>>>
>>> What's the battery nominal voltage supposed to be?
>>>
>>> -John
>>>
>>> ==========
>>>
>>>
>>>> Hi everyone!
>>>>
>>>> My SR620 is giving me an error 3 on power up. The manual says it's most
>>>> likely a dead backup battery.
>>>>
>>>> I can clear it if I hold down the reset button while powering up. (This
>>>> loads the factory defaults into the RAM.)
>>>>
>>>> However if I cycle power the error 3 comes back!
>>>>
>>>> The battery reads 3.44VDC and at the VCC pin of the Ram you get 3.20VDC
>>>> with the AC power off.
>>>>
>>>> This seems to indicate the battery is good.
>>>>
>>>> I'm thinking of placing a 1K resistor across the battery to see if a
>>>> load
>>>> will cause a big drop.
>>>>
>>>> Any suggestions?
>>>>
>>>> The RAM is a CXK58257AP-70L.
>>>>
>>>> Thanks,
>>>>
>>>> Corby Dawson
>>>> ____________________________________________________________
>>>> SHOCKING: 2010 Honda Civic for $1,734.09
>>>> Is this price real? YES! We reveal the TRUTH!
>>>> http://thirdpartyoffers.juno.com/TGL3141/4cc60781dcc8a5aca4m04duc
>>>>
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>>>
>>>
>>>
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>>
>>
>>
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